From 1dd629bd10885940a2ffe9c978361d5b296d05e9 Mon Sep 17 00:00:00 2001
From: Daniel Stonier <d.stonier@gmail.com>
Date: Sun, 8 Sep 2013 15:58:18 +0900
Subject: [PATCH] bringing in message_generator and updating gradle_plugins.

---
 build.gradle                                  |   1 -
 gradle_plugins/build.gradle                   |  24 +
 .../ros/gradle_plugins/CatkinPlugin.groovy    | 117 +++
 .../META-INF/gradle-plugins/catkin.properties |   1 +
 message_generator/build.gradle                |  38 +
 .../exception/RosMessageRuntimeException.java |  36 +
 .../java/org/ros/exception/package-info.java  |  20 +
 .../message/DefaultMessageDeserializer.java   |  50 ++
 .../message/DefaultMessageFactory.java        |  51 ++
 .../DefaultMessageInterfaceClassProvider.java |  55 ++
 .../DefaultMessageSerializationFactory.java   |  80 ++
 .../message/DefaultMessageSerializer.java     |  36 +
 .../internal/message/GenerateInterfaces.java  | 172 +++++
 .../org/ros/internal/message/GetInstance.java |  25 +
 .../ros/internal/message/Md5Generator.java    |  96 +++
 .../org/ros/internal/message/Message.java     |  28 +
 .../internal/message/MessageBufferPool.java   |  91 +++
 .../ros/internal/message/MessageBuffers.java  |  44 ++
 .../org/ros/internal/message/MessageImpl.java | 491 ++++++++++++
 .../message/MessageInterfaceBuilder.java      | 193 +++++
 .../MessageInterfaceClassProvider.java        |  32 +
 .../internal/message/MessageProxyFactory.java |  80 ++
 .../MessageProxyInvocationHandler.java        |  51 ++
 .../org/ros/internal/message/RawMessage.java  | 207 +++++
 .../internal/message/StringFileProvider.java  | 130 ++++
 .../message/StringResourceProvider.java       |  73 ++
 .../message/context/MessageContext.java       | 144 ++++
 .../context/MessageContextBuilder.java        |  85 +++
 .../context/MessageContextProvider.java       |  55 ++
 .../MessageDefinitionFileProvider.java        | 114 +++
 .../definition/MessageDefinitionParser.java   | 176 +++++
 .../MessageDefinitionProviderChain.java       |  86 +++
 .../MessageDefinitionReflectionProvider.java  |  88 +++
 .../MessageDefinitionTupleParser.java         |  68 ++
 .../message/field/BooleanArrayField.java      | 117 +++
 .../message/field/ByteArrayField.java         | 117 +++
 .../message/field/ChannelBufferField.java     | 118 +++
 .../message/field/DoubleArrayField.java       | 117 +++
 .../org/ros/internal/message/field/Field.java | 113 +++
 .../internal/message/field/FieldFactory.java  |  25 +
 .../ros/internal/message/field/FieldType.java |  50 ++
 .../message/field/FloatArrayField.java        | 117 +++
 .../message/field/IntegerArrayField.java      | 117 +++
 .../ros/internal/message/field/ListField.java | 115 +++
 .../message/field/LongArrayField.java         | 119 +++
 .../message/field/MessageFieldType.java       | 136 ++++
 .../internal/message/field/MessageFields.java | 116 +++
 .../message/field/PrimitiveFieldType.java     | 714 ++++++++++++++++++
 .../message/field/ShortArrayField.java        | 117 +++
 .../internal/message/field/ValueField.java    | 110 +++
 .../ros/internal/message/package-info.java    |  22 +
 .../ServiceDefinitionFileProvider.java        |  51 ++
 .../ServiceDefinitionResourceProvider.java    |  69 ++
 .../message/service/ServiceDescription.java   |  98 +++
 .../service/ServiceDescriptionFactory.java    |  44 ++
 .../service/ServiceRequestMessageFactory.java |  50 ++
 ...eRequestMessageInterfaceClassProvider.java |  37 +
 .../ServiceResponseMessageFactory.java        |  50 ++
 ...ResponseMessageInterfaceClassProvider.java |  37 +
 .../message/service/package-info.java         |  22 +
 .../topic/TopicDefinitionFileProvider.java    |  51 ++
 .../TopicDefinitionResourceProvider.java      |  68 ++
 .../message/topic/TopicDescription.java       |  69 ++
 .../topic/TopicDescriptionFactory.java        |  44 ++
 .../message/topic/TopicMessageFactory.java    |  30 +
 .../internal/message/topic/package-info.java  |  22 +
 .../main/java/org/ros/message/Duration.java   | 167 ++++
 .../org/ros/message/MessageDeclaration.java   | 108 +++
 .../message/MessageDefinitionProvider.java    |  50 ++
 .../org/ros/message/MessageDeserializer.java  |  31 +
 .../java/org/ros/message/MessageFactory.java  |  30 +
 .../ros/message/MessageFactoryProvider.java   |  24 +
 .../org/ros/message/MessageIdentifier.java    | 121 +++
 .../java/org/ros/message/MessageListener.java |  36 +
 .../message/MessageSerializationFactory.java  |  75 ++
 .../org/ros/message/MessageSerializer.java    |  30 +
 .../src/main/java/org/ros/message/Time.java   | 156 ++++
 .../java/org/ros/message/package-info.java    |  22 +
 package.xml                                   |  16 +
 settings.gradle                               |   3 +-
 80 files changed, 6987 insertions(+), 2 deletions(-)
 create mode 100644 gradle_plugins/build.gradle
 create mode 100644 gradle_plugins/src/main/groovy/org/ros/gradle_plugins/CatkinPlugin.groovy
 create mode 100644 gradle_plugins/src/main/resources/META-INF/gradle-plugins/catkin.properties
 create mode 100644 message_generator/build.gradle
 create mode 100644 message_generator/src/main/java/org/ros/exception/RosMessageRuntimeException.java
 create mode 100644 message_generator/src/main/java/org/ros/exception/package-info.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/DefaultMessageDeserializer.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/DefaultMessageFactory.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/DefaultMessageInterfaceClassProvider.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/DefaultMessageSerializationFactory.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/DefaultMessageSerializer.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/GenerateInterfaces.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/GetInstance.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/Md5Generator.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/Message.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/MessageBufferPool.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/MessageBuffers.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/MessageImpl.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/MessageInterfaceBuilder.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/MessageInterfaceClassProvider.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/MessageProxyFactory.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/MessageProxyInvocationHandler.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/RawMessage.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/StringFileProvider.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/StringResourceProvider.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/context/MessageContext.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/context/MessageContextBuilder.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/context/MessageContextProvider.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionFileProvider.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionParser.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionProviderChain.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionReflectionProvider.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionTupleParser.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/field/BooleanArrayField.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/field/ByteArrayField.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/field/ChannelBufferField.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/field/DoubleArrayField.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/field/Field.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/field/FieldFactory.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/field/FieldType.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/field/FloatArrayField.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/field/IntegerArrayField.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/field/ListField.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/field/LongArrayField.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/field/MessageFieldType.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/field/MessageFields.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/field/PrimitiveFieldType.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/field/ShortArrayField.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/field/ValueField.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/package-info.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/service/ServiceDefinitionFileProvider.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/service/ServiceDefinitionResourceProvider.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/service/ServiceDescription.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/service/ServiceDescriptionFactory.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/service/ServiceRequestMessageFactory.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/service/ServiceRequestMessageInterfaceClassProvider.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/service/ServiceResponseMessageFactory.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/service/ServiceResponseMessageInterfaceClassProvider.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/service/package-info.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/topic/TopicDefinitionFileProvider.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/topic/TopicDefinitionResourceProvider.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/topic/TopicDescription.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/topic/TopicDescriptionFactory.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/topic/TopicMessageFactory.java
 create mode 100644 message_generator/src/main/java/org/ros/internal/message/topic/package-info.java
 create mode 100644 message_generator/src/main/java/org/ros/message/Duration.java
 create mode 100644 message_generator/src/main/java/org/ros/message/MessageDeclaration.java
 create mode 100644 message_generator/src/main/java/org/ros/message/MessageDefinitionProvider.java
 create mode 100644 message_generator/src/main/java/org/ros/message/MessageDeserializer.java
 create mode 100644 message_generator/src/main/java/org/ros/message/MessageFactory.java
 create mode 100644 message_generator/src/main/java/org/ros/message/MessageFactoryProvider.java
 create mode 100644 message_generator/src/main/java/org/ros/message/MessageIdentifier.java
 create mode 100644 message_generator/src/main/java/org/ros/message/MessageListener.java
 create mode 100644 message_generator/src/main/java/org/ros/message/MessageSerializationFactory.java
 create mode 100644 message_generator/src/main/java/org/ros/message/MessageSerializer.java
 create mode 100644 message_generator/src/main/java/org/ros/message/Time.java
 create mode 100644 message_generator/src/main/java/org/ros/message/package-info.java
 create mode 100644 package.xml

diff --git a/build.gradle b/build.gradle
index a994432..bd3fd6c 100644
--- a/build.gradle
+++ b/build.gradle
@@ -21,7 +21,6 @@ task wrapper(type: Wrapper) {
 
 allprojects {
     group='org.ros.rosjava_bootstrap'
-    version='0.1.0-SNAPSHOT'
 }
 
 subprojects {
diff --git a/gradle_plugins/build.gradle b/gradle_plugins/build.gradle
new file mode 100644
index 0000000..3f1428a
--- /dev/null
+++ b/gradle_plugins/build.gradle
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2013 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+apply plugin: 'groovy'
+
+version='0.1.0'
+
+dependencies {
+    compile gradleApi()
+    groovy localGroovy()
+}
diff --git a/gradle_plugins/src/main/groovy/org/ros/gradle_plugins/CatkinPlugin.groovy b/gradle_plugins/src/main/groovy/org/ros/gradle_plugins/CatkinPlugin.groovy
new file mode 100644
index 0000000..2d2f2b5
--- /dev/null
+++ b/gradle_plugins/src/main/groovy/org/ros/gradle_plugins/CatkinPlugin.groovy
@@ -0,0 +1,117 @@
+package org.ros.gradle_plugins;
+
+import org.gradle.api.Project;
+import org.gradle.api.Plugin;
+import org.gradle.api.Task;
+import org.gradle.api.*;
+
+/*
+ * Provides catkin information to the gradle build, defining properties:
+ *
+ * - project.catkin.rosPackagePath : list of Strings
+ * - project.catkin.packages : dictionary of CatkinPackage objects
+ * 
+ * The latter can be iterated over for information:
+ *
+ * project.catkin.packages.each { pair ->
+ *     pkg = pair.value
+ *     println pkg.name
+ *     println pkg.version
+ *     pkg.dependencies.each { d ->
+ *         println d
+ *     }
+ *     // filtered list of *_msg dependencies.
+ *     pkg.messageDependencies().each { d ->
+ *         println d
+ *     }
+ * }
+ * 
+ * Use this only once in the root of a multi-project gradle build - it will
+ * only generate the properties once and share them this way.
+ */
+class CatkinPlugin implements Plugin<Project> {
+    /* 
+     * Possibly should check for existence of these properties and 
+     * be lazy if they're already defined.
+     */
+	def void apply(Project project) {
+	    project.extensions.create("catkin", CatkinPluginExtension)
+	    project.catkin.packages = [:]
+	    project.catkin.rosPackagePath = []
+	    project.catkin.rosPackagePath = "$System.env.ROS_PACKAGE_PATH".split(":")
+	    project.catkin.rosPackagePath.each { rosPackageRoot ->
+            def manifestTree = project.fileTree(dir: rosPackageRoot, include: '**/package.xml')
+            manifestTree.each { file -> 
+                def pkg = new CatkinPackage(file)
+                project.catkin.packages.put(pkg.name, pkg)
+            }
+	    }
+        println("CatkinPlugin is happy, you should be too.")
+        project.task('catkinPackageInfo') << {
+            println("CatkinPlugin is happy, you should be too.")
+            println("rosPackagePath........." + project.catkin.rosPackagePath)
+            println("Catkin Packages")
+            project.catkin.packages.each { pkg ->
+                print pkg.value.toString()
+            }
+        }
+    }
+}
+
+class CatkinPluginExtension {
+    Map<String, CatkinPackage> packages
+    List<String> rosPackagePath
+}
+
+/*
+ * Use this to establish methods that can be used by the project.
+ * Currently don't have any.
+ */
+class CatkinPluginConvention {
+    private Project project
+    public CatkinPluginConvention(Project project) {
+        this.project = project
+    }
+}
+
+class CatkinPackage {
+    def name
+    def version
+    def dependencies
+    
+    def CatkinPackage(File packageXmlFilename) {
+        def packageXml = new XmlParser().parse(packageXmlFilename)
+        name = packageXml.name.text()
+        version = packageXml.version.text()
+        dependencies = []
+        packageXml.build_depend.each { d ->
+            dependencies.add(d.text())
+        }
+    }
+    def String toString() {
+        def out = new String()
+        out += name + "\n"
+        out += "  version: " + version + "\n"
+        out += "  dependencies:" + "\n"
+        dependencies.each { d ->
+            out += "    " + d + "\n"
+        }
+        return out
+    }
+    /*
+     * Find and annotate a list of package package dependencies.
+     * Useful for message artifact generation).
+     *
+     * @return List<String> : dependencies (package name strings)  
+     */
+    def List<String> messageDependencies() {
+        List<String> msgDependencies = []
+        dependencies.each { d ->
+            if ( d.contains("_msgs") || d.contains("_srvs") ) {
+                msgDependencies.add(d)
+            }
+        }
+        return msgDependencies
+    }
+}
+
diff --git a/gradle_plugins/src/main/resources/META-INF/gradle-plugins/catkin.properties b/gradle_plugins/src/main/resources/META-INF/gradle-plugins/catkin.properties
new file mode 100644
index 0000000..687eec7
--- /dev/null
+++ b/gradle_plugins/src/main/resources/META-INF/gradle-plugins/catkin.properties
@@ -0,0 +1 @@
+implementation-class=org.ros.gradle_plugins.CatkinPlugin
\ No newline at end of file
diff --git a/message_generator/build.gradle b/message_generator/build.gradle
new file mode 100644
index 0000000..325acdb
--- /dev/null
+++ b/message_generator/build.gradle
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+version='0.1.0'
+
+dependencies {
+/*
+  testCompile 'junit:junit:4.8.2'
+  */
+  compile 'io.netty:netty:3.5.2.Final'
+  compile 'com.google.guava:guava:12.0'
+  compile 'org.apache.commons:com.springsource.org.apache.commons.codec:1.3.0'
+  compile 'org.apache.commons:com.springsource.org.apache.commons.io:1.4.0'
+  compile 'commons-pool:commons-pool:1.6'
+  compile 'org.apache.commons:com.springsource.org.apache.commons.lang:2.4.0'
+}
+
+jar {
+  manifest {
+    version = '0.1.0'
+    symbolicName = 'org.ros.rosjava_messages.message_generator'
+  }
+}
+
+
diff --git a/message_generator/src/main/java/org/ros/exception/RosMessageRuntimeException.java b/message_generator/src/main/java/org/ros/exception/RosMessageRuntimeException.java
new file mode 100644
index 0000000..b48b9b8
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/exception/RosMessageRuntimeException.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.exception;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ * @author d.stonier@gmail.com (Daniel Stonier)
+ */
+public class RosMessageRuntimeException extends RuntimeException {
+
+  public RosMessageRuntimeException(final Throwable throwable) {
+    super(throwable);
+  }
+
+  public RosMessageRuntimeException(final String message, final Throwable throwable) {
+    super(message, throwable);
+  }
+
+  public RosMessageRuntimeException(final String message) {
+    super(message);
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/exception/package-info.java b/message_generator/src/main/java/org/ros/exception/package-info.java
new file mode 100644
index 0000000..895f12d
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/exception/package-info.java
@@ -0,0 +1,20 @@
+/*
+ * Copyright (C) 2012 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+/**
+ * Provides the classes for representing common rosjava exceptions.
+ */
+package org.ros.exception;
\ No newline at end of file
diff --git a/message_generator/src/main/java/org/ros/internal/message/DefaultMessageDeserializer.java b/message_generator/src/main/java/org/ros/internal/message/DefaultMessageDeserializer.java
new file mode 100644
index 0000000..507f1c9
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/DefaultMessageDeserializer.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.ros.internal.message.field.Field;
+import org.ros.message.MessageDeserializer;
+import org.ros.message.MessageFactory;
+import org.ros.message.MessageIdentifier;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class DefaultMessageDeserializer<T> implements MessageDeserializer<T> {
+
+  private final MessageIdentifier messageIdentifier;
+  private final MessageFactory messageFactory;
+
+  public DefaultMessageDeserializer(MessageIdentifier messageIdentifier,
+      MessageFactory messageFactory) {
+    this.messageIdentifier = messageIdentifier;
+    this.messageFactory = messageFactory;
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public T deserialize(ChannelBuffer buffer) {
+    Message message = messageFactory.newFromType(messageIdentifier.getType());
+    for (Field field : message.toRawMessage().getFields()) {
+      if (!field.isConstant()) {
+        field.deserialize(buffer);
+      }
+    }
+    return (T) message;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/DefaultMessageFactory.java b/message_generator/src/main/java/org/ros/internal/message/DefaultMessageFactory.java
new file mode 100644
index 0000000..97d817e
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/DefaultMessageFactory.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+import com.google.common.annotations.VisibleForTesting;
+
+import org.ros.message.MessageDeclaration;
+import org.ros.message.MessageDefinitionProvider;
+import org.ros.message.MessageFactory;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class DefaultMessageFactory implements MessageFactory {
+
+  private final MessageDefinitionProvider messageDefinitionProvider;
+  private final DefaultMessageInterfaceClassProvider messageInterfaceClassProvider;
+  private final MessageProxyFactory messageProxyFactory;
+
+  public DefaultMessageFactory(MessageDefinitionProvider messageDefinitionProvider) {
+    this.messageDefinitionProvider = messageDefinitionProvider;
+    messageInterfaceClassProvider = new DefaultMessageInterfaceClassProvider();
+    messageProxyFactory = new MessageProxyFactory(getMessageInterfaceClassProvider(), this);
+  }
+
+  @Override
+  public <T> T newFromType(String messageType) {
+    String messageDefinition = messageDefinitionProvider.get(messageType);
+    MessageDeclaration messageDeclaration = MessageDeclaration.of(messageType, messageDefinition);
+    return messageProxyFactory.newMessageProxy(messageDeclaration);
+  }
+
+  @VisibleForTesting
+  DefaultMessageInterfaceClassProvider getMessageInterfaceClassProvider() {
+    return messageInterfaceClassProvider;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/DefaultMessageInterfaceClassProvider.java b/message_generator/src/main/java/org/ros/internal/message/DefaultMessageInterfaceClassProvider.java
new file mode 100644
index 0000000..8de583d
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/DefaultMessageInterfaceClassProvider.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.collect.Maps;
+
+import java.util.Map;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class DefaultMessageInterfaceClassProvider implements MessageInterfaceClassProvider {
+
+  private final Map<String, Class<?>> cache;
+
+  public DefaultMessageInterfaceClassProvider() {
+    cache = Maps.newConcurrentMap();
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public <T> Class<T> get(String messageType) {
+    if (cache.containsKey(messageType)) {
+      return (Class<T>) cache.get(messageType);
+    }
+    try {
+      String className = messageType.replace("/", ".");
+      Class<T> messageInterfaceClass = (Class<T>) getClass().getClassLoader().loadClass(className);
+      cache.put(messageType, messageInterfaceClass);
+      return messageInterfaceClass;
+    } catch (ClassNotFoundException e) {
+      return (Class<T>) RawMessage.class;
+    }
+  }
+
+  @VisibleForTesting
+  <T> void add(String messageType, Class<T> messageInterfaceClass) {
+    cache.put(messageType, messageInterfaceClass);
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/DefaultMessageSerializationFactory.java b/message_generator/src/main/java/org/ros/internal/message/DefaultMessageSerializationFactory.java
new file mode 100644
index 0000000..726b5d8
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/DefaultMessageSerializationFactory.java
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+import org.ros.internal.message.service.ServiceRequestMessageFactory;
+import org.ros.internal.message.service.ServiceResponseMessageFactory;
+import org.ros.message.MessageDefinitionProvider;
+import org.ros.message.MessageDeserializer;
+import org.ros.message.MessageFactory;
+import org.ros.message.MessageIdentifier;
+import org.ros.message.MessageSerializationFactory;
+import org.ros.message.MessageSerializer;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class DefaultMessageSerializationFactory implements MessageSerializationFactory {
+
+  private final MessageFactory topicMessageFactory;
+  private final ServiceRequestMessageFactory serviceRequestMessageFactory;
+  private final ServiceResponseMessageFactory serviceResponseMessageFactory;
+
+  public DefaultMessageSerializationFactory(MessageDefinitionProvider messageDefinitionProvider) {
+    topicMessageFactory = new DefaultMessageFactory(messageDefinitionProvider);
+    serviceRequestMessageFactory = new ServiceRequestMessageFactory(messageDefinitionProvider);
+    serviceResponseMessageFactory = new ServiceResponseMessageFactory(messageDefinitionProvider);
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public <T> MessageSerializer<T> newMessageSerializer(String messageType) {
+    return (MessageSerializer<T>) new DefaultMessageSerializer();
+  }
+
+  @Override
+  public <T> MessageDeserializer<T> newMessageDeserializer(String messageType) {
+    return new DefaultMessageDeserializer<T>(MessageIdentifier.of(messageType),
+        topicMessageFactory);
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public <T> MessageSerializer<T> newServiceRequestSerializer(String serviceType) {
+    return (MessageSerializer<T>) new DefaultMessageSerializer();
+  }
+
+  @Override
+  public <T> org.ros.message.MessageDeserializer<T>
+      newServiceRequestDeserializer(String serviceType) {
+    return new DefaultMessageDeserializer<T>(MessageIdentifier.of(serviceType),
+        serviceRequestMessageFactory);
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public <T> org.ros.message.MessageSerializer<T> newServiceResponseSerializer(String serviceType) {
+    return (MessageSerializer<T>) new DefaultMessageSerializer();
+  }
+
+  @Override
+  public <T> org.ros.message.MessageDeserializer<T> newServiceResponseDeserializer(
+      String serviceType) {
+    return new DefaultMessageDeserializer<T>(MessageIdentifier.of(serviceType),
+        serviceResponseMessageFactory);
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/DefaultMessageSerializer.java b/message_generator/src/main/java/org/ros/internal/message/DefaultMessageSerializer.java
new file mode 100644
index 0000000..a71a597
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/DefaultMessageSerializer.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.ros.internal.message.field.Field;
+import org.ros.message.MessageSerializer;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class DefaultMessageSerializer implements MessageSerializer<Message> {
+
+  @Override
+  public void serialize(Message message, ChannelBuffer buffer) {
+    for (Field field : message.toRawMessage().getFields()) {
+      if (!field.isConstant()) {
+        field.serialize(buffer);
+      }
+    }
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/GenerateInterfaces.java b/message_generator/src/main/java/org/ros/internal/message/GenerateInterfaces.java
new file mode 100644
index 0000000..c057fd4
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/GenerateInterfaces.java
@@ -0,0 +1,172 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+import com.google.common.collect.Lists;
+import com.google.common.collect.Sets;
+
+import org.apache.commons.io.FileUtils;
+import org.ros.exception.RosMessageRuntimeException;
+import org.ros.internal.message.definition.MessageDefinitionProviderChain;
+import org.ros.internal.message.definition.MessageDefinitionTupleParser;
+import org.ros.internal.message.service.ServiceDefinitionFileProvider;
+import org.ros.internal.message.topic.TopicDefinitionFileProvider;
+import org.ros.message.MessageDeclaration;
+import org.ros.message.MessageFactory;
+import org.ros.message.MessageIdentifier;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class GenerateInterfaces {
+
+  private final TopicDefinitionFileProvider topicDefinitionFileProvider;
+  private final ServiceDefinitionFileProvider serviceDefinitionFileProvider;
+  private final MessageDefinitionProviderChain messageDefinitionProviderChain;
+  private final MessageFactory messageFactory;
+  static private final String ROS_PACKAGE_PATH = "ROS_PACKAGE_PATH";
+
+  public GenerateInterfaces() {
+    messageDefinitionProviderChain = new MessageDefinitionProviderChain();
+    topicDefinitionFileProvider = new TopicDefinitionFileProvider();
+    messageDefinitionProviderChain.addMessageDefinitionProvider(topicDefinitionFileProvider);
+    serviceDefinitionFileProvider = new ServiceDefinitionFileProvider();
+    messageDefinitionProviderChain.addMessageDefinitionProvider(serviceDefinitionFileProvider);
+    messageFactory = new DefaultMessageFactory(messageDefinitionProviderChain);
+  }
+
+  /**
+   * @param packages
+   *          a list of packages containing the topic types to generate
+   *          interfaces for
+   * @param outputDirectory
+   *          the directory to write the generated interfaces to
+   * @throws IOException
+   */
+  private void writeTopicInterfaces(File outputDirectory, Collection<String> packages)
+      throws IOException {
+    Collection<MessageIdentifier> topicTypes = Sets.newHashSet();
+    if (packages.size() == 0) {
+      packages = topicDefinitionFileProvider.getPackages();
+    }
+    for (String pkg : packages) {
+      Collection<MessageIdentifier> messageIdentifiers =
+          topicDefinitionFileProvider.getMessageIdentifiersByPackage(pkg);
+      if (messageIdentifiers != null) {
+        topicTypes.addAll(messageIdentifiers);
+      }
+    }
+    for (MessageIdentifier topicType : topicTypes) {
+      String definition = messageDefinitionProviderChain.get(topicType.getType());
+      MessageDeclaration messageDeclaration = new MessageDeclaration(topicType, definition);
+      writeInterface(messageDeclaration, outputDirectory, true);
+    }
+  }
+
+  /**
+   * @param packages
+   *          a list of packages containing the topic types to generate
+   *          interfaces for
+   * @param outputDirectory
+   *          the directory to write the generated interfaces to
+   * @throws IOException
+   */
+  private void writeServiceInterfaces(File outputDirectory, Collection<String> packages)
+      throws IOException {
+    Collection<MessageIdentifier> serviceTypes = Sets.newHashSet();
+    if (packages.size() == 0) {
+      packages = serviceDefinitionFileProvider.getPackages();
+    }
+    for (String pkg : packages) {
+      Collection<MessageIdentifier> messageIdentifiers =
+          serviceDefinitionFileProvider.getMessageIdentifiersByPackage(pkg);
+      if (messageIdentifiers != null) {
+        serviceTypes.addAll(messageIdentifiers);
+      }
+    }
+    for (MessageIdentifier serviceType : serviceTypes) {
+      String definition = messageDefinitionProviderChain.get(serviceType.getType());
+      MessageDeclaration serviceDeclaration =
+          MessageDeclaration.of(serviceType.getType(), definition);
+      writeInterface(serviceDeclaration, outputDirectory, false);
+      List<String> requestAndResponse = MessageDefinitionTupleParser.parse(definition, 2);
+      MessageDeclaration requestDeclaration =
+          MessageDeclaration.of(serviceType.getType() + "Request", requestAndResponse.get(0));
+      MessageDeclaration responseDeclaration =
+          MessageDeclaration.of(serviceType.getType() + "Response", requestAndResponse.get(1));
+      writeInterface(requestDeclaration, outputDirectory, true);
+      writeInterface(responseDeclaration, outputDirectory, true);
+    }
+  }
+
+  private void writeInterface(MessageDeclaration messageDeclaration, File outputDirectory,
+      boolean addConstantsAndMethods) {
+    MessageInterfaceBuilder builder = new MessageInterfaceBuilder();
+    builder.setPackageName(messageDeclaration.getPackage());
+    builder.setInterfaceName(messageDeclaration.getName());
+    builder.setMessageDeclaration(messageDeclaration);
+    builder.setAddConstantsAndMethods(addConstantsAndMethods);
+    try {
+      String content;
+      content = builder.build(messageFactory);
+      File file = new File(outputDirectory, messageDeclaration.getType() + ".java");
+      FileUtils.writeStringToFile(file, content);
+    } catch (Exception e) {
+      System.out.printf("Failed to generate interface for %s.\n", messageDeclaration.getType());
+      e.printStackTrace();
+    }
+  }
+
+  public void generate(File outputDirectory, Collection<String> packages,
+      Collection<File> packagePath) {
+    for (File directory : packagePath) {
+      topicDefinitionFileProvider.addDirectory(directory);
+      serviceDefinitionFileProvider.addDirectory(directory);
+    }
+    topicDefinitionFileProvider.update();
+    serviceDefinitionFileProvider.update();
+    try {
+      writeTopicInterfaces(outputDirectory, packages);
+      writeServiceInterfaces(outputDirectory, packages);
+    } catch (IOException e) {
+      throw new RosMessageRuntimeException(e);
+    }
+  }
+
+  public static void main(String[] args) {
+    List<String> arguments = Lists.newArrayList(args);
+    if (arguments.size() == 0) {
+      arguments.add(".");
+    }
+    String rosPackagePath = System.getenv(ROS_PACKAGE_PATH);
+    Collection<File> packagePath = Lists.newArrayList();
+    for (String path : rosPackagePath.split(File.pathSeparator)) {
+      File packageDirectory = new File(path);
+      if (packageDirectory.exists()) {
+        packagePath.add(packageDirectory);
+      }
+    }
+    GenerateInterfaces generateInterfaces = new GenerateInterfaces();
+    File outputDirectory = new File(arguments.remove(0));
+    generateInterfaces.generate(outputDirectory, arguments, packagePath);
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/GetInstance.java b/message_generator/src/main/java/org/ros/internal/message/GetInstance.java
new file mode 100644
index 0000000..5916b94
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/GetInstance.java
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+interface GetInstance {
+
+  public Object getInstance();
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/Md5Generator.java b/message_generator/src/main/java/org/ros/internal/message/Md5Generator.java
new file mode 100644
index 0000000..0e78b79
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/Md5Generator.java
@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.Lists;
+
+import org.ros.internal.message.definition.MessageDefinitionParser;
+import org.ros.internal.message.definition.MessageDefinitionTupleParser;
+import org.ros.internal.message.definition.MessageDefinitionParser.MessageDefinitionVisitor;
+
+import org.apache.commons.codec.digest.DigestUtils;
+import org.ros.internal.message.field.PrimitiveFieldType;
+import org.ros.message.MessageDefinitionProvider;
+
+import java.util.List;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class Md5Generator {
+
+  private final MessageDefinitionProvider messageDefinitionProvider;
+
+  public Md5Generator(MessageDefinitionProvider messageDefinitionProvider) {
+    this.messageDefinitionProvider = messageDefinitionProvider;
+  }
+
+  public String generate(String messageType) {
+    String messageDefinition = messageDefinitionProvider.get(messageType);
+    Preconditions.checkNotNull(messageDefinition, "No definition for message type: " + messageType);
+    List<String> parts = MessageDefinitionTupleParser.parse(messageDefinition, -1);
+    StringBuilder text = new StringBuilder();
+    for (String part : parts) {
+      text.append(generateText(messageType, part));
+    }
+    return DigestUtils.md5Hex(text.toString());
+  }
+
+  private String generateText(String messageType, String messageDefinition) {
+    final List<String> constants = Lists.newArrayList();
+    final List<String> variables = Lists.newArrayList();
+    MessageDefinitionVisitor visitor = new MessageDefinitionVisitor() {
+      @Override
+      public void variableValue(String type, String name) {
+        if (!PrimitiveFieldType.existsFor(type)) {
+          type = generate(type);
+        }
+        variables.add(String.format("%s %s\n", type, name));
+      }
+
+      @Override
+      public void variableList(String type, int size, String name) {
+        if (!PrimitiveFieldType.existsFor(type)) {
+          String md5Checksum = generate(type);
+          variables.add(String.format("%s %s\n", md5Checksum, name));
+        } else {
+          if (size != -1) {
+            variables.add(String.format("%s[%d] %s\n", type, size, name));
+          } else {
+            variables.add(String.format("%s[] %s\n", type, name));
+          }
+        }
+      }
+
+      @Override
+      public void constantValue(String type, String name, String value) {
+        constants.add(String.format("%s %s=%s\n", type, name, value));
+      }
+    };
+    MessageDefinitionParser messageDefinitionParser = new MessageDefinitionParser(visitor);
+    messageDefinitionParser.parse(messageType, messageDefinition);
+    String text = "";
+    for (String constant : constants) {
+      text += constant;
+    }
+    for (String variable : variables) {
+      text += variable;
+    }
+    return text.trim();
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/Message.java b/message_generator/src/main/java/org/ros/internal/message/Message.java
new file mode 100644
index 0000000..055db82
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/Message.java
@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2012 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public interface Message {
+
+  /**
+   * @return returns this {@link Message} as a {@link RawMessage}
+   */
+  RawMessage toRawMessage();
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/MessageBufferPool.java b/message_generator/src/main/java/org/ros/internal/message/MessageBufferPool.java
new file mode 100644
index 0000000..73246ed
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/MessageBufferPool.java
@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2012 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+import org.apache.commons.pool.ObjectPool;
+import org.apache.commons.pool.PoolableObjectFactory;
+import org.apache.commons.pool.impl.StackObjectPool;
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.ros.exception.RosMessageRuntimeException;
+
+/**
+ * A pool of {@link ChannelBuffer}s for serializing and deserializing messages.
+ * <p>
+ * By contract, {@link ChannelBuffer}s provided by {@link #acquire()} must be
+ * returned using {@link #release(ChannelBuffer)}.
+ * 
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class MessageBufferPool {
+
+  private final ObjectPool<ChannelBuffer> pool;
+
+  public MessageBufferPool() {
+    pool = new StackObjectPool<ChannelBuffer>(new PoolableObjectFactory<ChannelBuffer>() {
+      @Override
+      public ChannelBuffer makeObject() throws Exception {
+        return MessageBuffers.dynamicBuffer();
+      }
+
+      @Override
+      public void destroyObject(ChannelBuffer channelBuffer) throws Exception {
+      }
+
+      @Override
+      public boolean validateObject(ChannelBuffer channelBuffer) {
+        return true;
+      }
+
+      @Override
+      public void activateObject(ChannelBuffer channelBuffer) throws Exception {
+      }
+
+      @Override
+      public void passivateObject(ChannelBuffer channelBuffer) throws Exception {
+        channelBuffer.clear();
+      }
+    });
+  }
+
+  /**
+   * Acquired {@link ChannelBuffer}s must be returned using
+   * {@link #release(ChannelBuffer)}.
+   * 
+   * @return an unused {@link ChannelBuffer}
+   */
+  public ChannelBuffer acquire() {
+    try {
+      return pool.borrowObject();
+    } catch (Exception e) {
+      throw new RosMessageRuntimeException(e);
+    }
+  }
+
+  /**
+   * Release a previously acquired {@link ChannelBuffer}.
+   * 
+   * @param channelBuffer
+   *          the {@link ChannelBuffer} to release
+   */
+  public void release(ChannelBuffer channelBuffer) {
+    try {
+      pool.returnObject(channelBuffer);
+    } catch (Exception e) {
+      throw new RosMessageRuntimeException(e);
+    }
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/MessageBuffers.java b/message_generator/src/main/java/org/ros/internal/message/MessageBuffers.java
new file mode 100644
index 0000000..a5934ec
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/MessageBuffers.java
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2012 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.jboss.netty.buffer.ChannelBuffers;
+
+import java.nio.ByteOrder;
+
+/**
+ * Provides {@link ChannelBuffer}s for serializing and deserializing messages.
+ * 
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class MessageBuffers {
+
+  static final int ESTIMATED_LENGTH = 256;
+
+  private MessageBuffers() {
+    // Utility class.
+  }
+
+  /**
+   * @return a new {@link ChannelBuffer} for {@link Message} serialization that
+   *         grows dynamically
+   */
+  public static ChannelBuffer dynamicBuffer() {
+    return ChannelBuffers.dynamicBuffer(ByteOrder.LITTLE_ENDIAN, ESTIMATED_LENGTH);
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/MessageImpl.java b/message_generator/src/main/java/org/ros/internal/message/MessageImpl.java
new file mode 100644
index 0000000..d7824dc
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/MessageImpl.java
@@ -0,0 +1,491 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.ros.exception.RosMessageRuntimeException;
+import org.ros.internal.message.context.MessageContext;
+import org.ros.internal.message.field.Field;
+import org.ros.internal.message.field.MessageFieldType;
+import org.ros.internal.message.field.MessageFields;
+import org.ros.message.Duration;
+import org.ros.message.MessageIdentifier;
+import org.ros.message.Time;
+
+import java.util.List;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+class MessageImpl implements RawMessage, GetInstance {
+
+  private final MessageContext messageContext;
+  private final MessageFields messageFields;
+
+  public MessageImpl(MessageContext messageContext) {
+    this.messageContext = messageContext;
+    messageFields = new MessageFields(messageContext);
+  }
+
+  public MessageContext getMessageContext() {
+    return messageContext;
+  }
+
+  public MessageFields getMessageFields() {
+    return messageFields;
+  }
+
+  @Override
+  public RawMessage toRawMessage() {
+    return (RawMessage) this;
+  }
+
+  @Override
+  public MessageIdentifier getIdentifier() {
+    return messageContext.getMessageIdentifer();
+  }
+
+  @Override
+  public String getType() {
+    return messageContext.getType();
+  }
+
+  @Override
+  public String getPackage() {
+    return messageContext.getPackage();
+  }
+
+  @Override
+  public String getName() {
+    return messageContext.getName();
+  }
+
+  @Override
+  public String getDefinition() {
+    return messageContext.getDefinition();
+  }
+
+  @Override
+  public List<Field> getFields() {
+    return messageFields.getFields();
+  }
+
+  @Override
+  public boolean getBool(String name) {
+    return (Boolean) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public boolean[] getBoolArray(String name) {
+    return (boolean[]) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public Duration getDuration(String name) {
+    return (Duration) messageFields.getFieldValue(name);
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public List<Duration> getDurationList(String name) {
+    return (List<Duration>) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public float getFloat32(String name) {
+    return (Float) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public float[] getFloat32Array(String name) {
+    return (float[]) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public double getFloat64(String name) {
+    return (Double) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public double[] getFloat64Array(String name) {
+    return (double[]) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public short getInt16(String name) {
+    return (Short) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public short[] getInt16Array(String name) {
+    return (short[]) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public int getInt32(String name) {
+    return (Integer) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public int[] getInt32Array(String name) {
+    return (int[]) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public long getInt64(String name) {
+    return (Long) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public long[] getInt64Array(String name) {
+    return (long[]) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public byte getInt8(String name) {
+    return (Byte) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public byte[] getInt8Array(String name) {
+    return (byte[]) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public <T extends Message> T getMessage(String name) {
+    if (messageFields.getField(name).getType() instanceof MessageFieldType) {
+      return messageFields.getField(name).<T>getValue();
+    }
+    throw new RosMessageRuntimeException("Failed to access message field: " + name);
+  }
+
+  @Override
+  public <T extends Message> List<T> getMessageList(String name) {
+    if (messageFields.getField(name).getType() instanceof MessageFieldType) {
+      return messageFields.getField(name).<List<T>>getValue();
+    }
+    throw new RosMessageRuntimeException("Failed to access list field: " + name);
+  }
+
+  @Override
+  public String getString(String name) {
+    return (String) messageFields.getFieldValue(name);
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public List<String> getStringList(String name) {
+    return (List<String>) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public Time getTime(String name) {
+    return (Time) messageFields.getFieldValue(name);
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public List<Time> getTimeList(String name) {
+    return (List<Time>) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public short getUInt16(String name) {
+    return (Short) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public short[] getUInt16Array(String name) {
+    return (short[]) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public int getUInt32(String name) {
+    return (Integer) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public int[] getUInt32Array(String name) {
+    return (int[]) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public long getUInt64(String name) {
+    return (Long) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public long[] getUInt64Array(String name) {
+    return (long[]) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public short getUInt8(String name) {
+    return (Short) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public short[] getUInt8Array(String name) {
+    return (short[]) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public void setBool(String name, boolean value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setBoolArray(String name, boolean[] value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setDurationList(String name, List<Duration> value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setDuration(String name, Duration value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setFloat32(String name, float value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setFloat32Array(String name, float[] value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setFloat64(String name, double value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setFloat64Array(String name, double[] value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setInt16(String name, short value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setInt16Array(String name, short[] value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setInt32(String name, int value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setInt32Array(String name, int[] value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setInt64(String name, long value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setInt64Array(String name, long[] value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setInt8(String name, byte value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setInt8Array(String name, byte[] value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setMessage(String name, Message value) {
+    // TODO(damonkohler): Verify the type of the provided Message?
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setMessageList(String name, List<Message> value) {
+    // TODO(damonkohler): Verify the type of all Messages in the provided list?
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setString(String name, String value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setStringList(String name, List<String> value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setTime(String name, Time value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setTimeList(String name, List<Time> value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setUInt16(String name, short value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setUInt16Array(String name, short[] value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setUInt32(String name, int value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setUInt32Array(String name, int[] value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setUInt64(String name, long value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setUInt64Array(String name, long[] value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setUInt8(String name, byte value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setUInt8Array(String name, byte[] value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public byte getByte(String name) {
+    return (Byte) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public short getChar(String name) {
+    return (Short) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public void setByte(String name, byte value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setChar(String name, short value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setByteArray(String name, byte[] value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public void setCharArray(String name, short[] value) {
+    messageFields.setFieldValue(name, value);
+  }
+
+  @Override
+  public byte[] getByteArray(String name) {
+    return (byte[]) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public short[] getCharArray(String name) {
+    return (short[]) messageFields.getFieldValue(name);
+  }
+  
+  @Override
+  public ChannelBuffer getChannelBuffer(String name) {
+    return (ChannelBuffer) messageFields.getFieldValue(name);
+  }
+
+  @Override
+  public void setChannelBuffer(String name, ChannelBuffer value) {
+    messageFields.setFieldValue(name, value);
+  }
+  
+  @Override
+  public Object getInstance() {
+    return this;
+  }
+
+  @Override
+  public String toString() {
+    return String.format("MessageImpl<%s>", getType());
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = 1;
+    result = prime * result + ((messageContext == null) ? 0 : messageContext.hashCode());
+    result = prime * result + ((messageFields == null) ? 0 : messageFields.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (obj == null)
+      return false;
+    if (!(obj instanceof GetInstance))
+      return false;
+    obj = ((GetInstance) obj).getInstance();
+    if (getClass() != obj.getClass())
+      return false;
+    MessageImpl other = (MessageImpl) obj;
+    if (messageContext == null) {
+      if (other.messageContext != null)
+        return false;
+    } else if (!messageContext.equals(other.messageContext))
+      return false;
+    if (messageFields == null) {
+      if (other.messageFields != null)
+        return false;
+    } else if (!messageFields.equals(other.messageFields))
+      return false;
+    return true;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/MessageInterfaceBuilder.java b/message_generator/src/main/java/org/ros/internal/message/MessageInterfaceBuilder.java
new file mode 100644
index 0000000..43b8caa
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/MessageInterfaceBuilder.java
@@ -0,0 +1,193 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.Sets;
+
+import org.apache.commons.lang.StringEscapeUtils;
+import org.ros.exception.RosMessageRuntimeException;
+import org.ros.internal.message.context.MessageContext;
+import org.ros.internal.message.context.MessageContextProvider;
+import org.ros.internal.message.field.Field;
+import org.ros.internal.message.field.FieldType;
+import org.ros.internal.message.field.MessageFields;
+import org.ros.internal.message.field.PrimitiveFieldType;
+import org.ros.message.MessageDeclaration;
+import org.ros.message.MessageFactory;
+
+import java.util.Set;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class MessageInterfaceBuilder {
+
+  private MessageDeclaration messageDeclaration;
+  private String packageName;
+  private String interfaceName;
+  private boolean addConstantsAndMethods;
+  private String nestedContent;
+
+  // TODO(damonkohler): Upgrade Apache Commons Lang. See
+  // https://issues.apache.org/jira/browse/LANG-437
+  private static String escapeJava(String str) {
+    return StringEscapeUtils.escapeJava(str).replace("\\/", "/").replace("'", "\\'");
+  }
+
+  public MessageDeclaration getMessageDeclaration() {
+    return messageDeclaration;
+  }
+
+  public MessageInterfaceBuilder setMessageDeclaration(MessageDeclaration messageDeclaration) {
+    Preconditions.checkNotNull(messageDeclaration);
+    this.messageDeclaration = messageDeclaration;
+    return this;
+  }
+
+  public String getPackageName() {
+    return packageName;
+  }
+
+  /**
+   * @param packageName
+   *          the package name of the interface or {@code null} if no package
+   *          name should be specified
+   * @return this {@link MessageInterfaceBuilder}
+   */
+  public MessageInterfaceBuilder setPackageName(String packageName) {
+    this.packageName = packageName;
+    return this;
+  }
+
+  public String getInterfaceName() {
+    return interfaceName;
+  }
+
+  public MessageInterfaceBuilder setInterfaceName(String interfaceName) {
+    Preconditions.checkNotNull(interfaceName);
+    this.interfaceName = interfaceName;
+    return this;
+  }
+
+  public boolean getAddConstantsAndMethods() {
+    return addConstantsAndMethods;
+  }
+
+  public void setAddConstantsAndMethods(boolean enabled) {
+    addConstantsAndMethods = enabled;
+  }
+
+  public String getNestedContent() {
+    return nestedContent;
+  }
+
+  public void setNestedContent(String nestedContent) {
+    this.nestedContent = nestedContent;
+  }
+
+  public String build(MessageFactory messageFactory) {
+    Preconditions.checkNotNull(messageDeclaration);
+    Preconditions.checkNotNull(interfaceName);
+    StringBuilder builder = new StringBuilder();
+    if (packageName != null) {
+      builder.append(String.format("package %s;\n\n", packageName));
+    }
+    builder.append(String.format(
+        "public interface %s extends org.ros.internal.message.Message {\n", interfaceName));
+    builder.append(String.format("  static final java.lang.String _TYPE = \"%s\";\n",
+        messageDeclaration.getType()));
+    builder.append(String.format("  static final java.lang.String _DEFINITION = \"%s\";\n",
+        escapeJava(messageDeclaration.getDefinition())));
+    if (addConstantsAndMethods) {
+      MessageContextProvider messageContextProvider = new MessageContextProvider(messageFactory);
+      MessageContext messageContext = messageContextProvider.get(messageDeclaration);
+      appendConstants(messageContext, builder);
+      appendSettersAndGetters(messageContext, builder);
+    }
+    if (nestedContent != null) {
+      builder.append("\n");
+      builder.append(nestedContent);
+    }
+    builder.append("}\n");
+    return builder.toString();
+  }
+
+  @SuppressWarnings("deprecation")
+  private String getJavaValue(PrimitiveFieldType primitiveFieldType, String value) {
+    switch (primitiveFieldType) {
+      case BOOL:
+        return Boolean.valueOf(!value.equals("0") && !value.equals("false")).toString();
+      case FLOAT32:
+        return value + "f";
+      case STRING:
+        return "\"" + escapeJava(value) + "\"";
+      case BYTE:
+      case CHAR:
+      case INT8:
+      case UINT8:
+      case INT16:
+      case UINT16:
+      case INT32:
+      case UINT32:
+      case INT64:
+      case UINT64:
+      case FLOAT64:
+        return value;
+      default:
+        throw new RosMessageRuntimeException("Unsupported PrimitiveFieldType: " + primitiveFieldType);
+    }
+  }
+
+  private void appendConstants(MessageContext messageContext, StringBuilder builder) {
+    MessageFields messageFields = new MessageFields(messageContext);
+    for (Field field : messageFields.getFields()) {
+      if (field.isConstant()) {
+        Preconditions.checkState(field.getType() instanceof PrimitiveFieldType);
+        // We use FieldType and cast back to PrimitiveFieldType below to avoid a
+        // bug in the Sun JDK: http://gs.sun.com/view_bug.do?bug_id=6522780
+        FieldType fieldType = (FieldType) field.getType();
+        String value = getJavaValue((PrimitiveFieldType) fieldType, field.getValue().toString());
+        builder.append(String.format("  static final %s %s = %s;\n", fieldType.getJavaTypeName(),
+            field.getName(), value));
+      }
+    }
+  }
+
+  private void appendSettersAndGetters(MessageContext messageContext, StringBuilder builder) {
+    MessageFields messageFields = new MessageFields(messageContext);
+    Set<String> getters = Sets.newHashSet();
+    for (Field field : messageFields.getFields()) {
+      if (field.isConstant()) {
+        continue;
+      }
+      String type = field.getJavaTypeName();
+      String getter = messageContext.getFieldGetterName(field.getName());
+      String setter = messageContext.getFieldSetterName(field.getName());
+      if (getters.contains(getter)) {
+        // In the case that two or more message fields have the same name except
+        // for capitalization, we only generate a getter and setter pair for the
+        // first one. The following fields will only be accessible via the
+        // RawMessage interface.
+        continue;
+      }
+      getters.add(getter);
+      builder.append(String.format("  %s %s();\n", type, getter));
+      builder.append(String.format("  void %s(%s value);\n", setter, type));
+    }
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/MessageInterfaceClassProvider.java b/message_generator/src/main/java/org/ros/internal/message/MessageInterfaceClassProvider.java
new file mode 100644
index 0000000..544c315
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/MessageInterfaceClassProvider.java
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public interface MessageInterfaceClassProvider {
+
+  /**
+   * @param <T>
+   *          the message interface class type
+   * @param messageType
+   *          the type of message to provide an interface class for
+   * @return the interface class for the specified message type
+   */
+  <T> Class<T> get(String messageType);
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/MessageProxyFactory.java b/message_generator/src/main/java/org/ros/internal/message/MessageProxyFactory.java
new file mode 100644
index 0000000..cc2e7f2
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/MessageProxyFactory.java
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+import com.google.common.base.Preconditions;
+
+import org.ros.internal.message.context.MessageContext;
+import org.ros.internal.message.context.MessageContextProvider;
+import org.ros.message.MessageDeclaration;
+import org.ros.message.MessageFactory;
+
+import java.lang.reflect.Proxy;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class MessageProxyFactory {
+
+  // We can't use the constant here since the rosjava_messages package depends
+  // on rosjava_bootstrap.
+  private static final String HEADER_MESSAGE_TYPE = "std_msgs/Header";
+  private static final String SEQUENCE_FIELD_NAME = "seq";
+  private static final AtomicInteger SEQUENCE_NUMBER = new AtomicInteger(0);
+
+  private final MessageInterfaceClassProvider messageInterfaceClassProvider;
+  private final MessageContextProvider messageContextProvider;
+
+  public MessageProxyFactory(MessageInterfaceClassProvider messageInterfaceClassProvider,
+      MessageFactory messageFactory) {
+    this.messageInterfaceClassProvider = messageInterfaceClassProvider;
+    messageContextProvider = new MessageContextProvider(messageFactory);
+  }
+
+  @SuppressWarnings("unchecked")
+  public <T> T newMessageProxy(MessageDeclaration messageDeclaration) {
+    Preconditions.checkNotNull(messageDeclaration);
+    MessageContext messageContext = messageContextProvider.get(messageDeclaration);
+    MessageImpl messageImpl = new MessageImpl(messageContext);
+    // Header messages are automatically populated with a monotonically
+    // increasing sequence number.
+    if (messageImpl.getType().equals(HEADER_MESSAGE_TYPE)) {
+      messageImpl.setUInt32(SEQUENCE_FIELD_NAME, SEQUENCE_NUMBER.getAndIncrement());
+    }
+    Class<T> messageInterfaceClass =
+        (Class<T>) messageInterfaceClassProvider.get(messageDeclaration.getType());
+    return newProxy(messageInterfaceClass, messageImpl);
+  }
+
+  /**
+   * @param interfaceClass
+   *          the interface class to provide
+   * @param messageImpl
+   *          the instance to proxy
+   * @return a new proxy for {@code implementation} that implements
+   *         {@code interfaceClass}
+   */
+  @SuppressWarnings("unchecked")
+  private <T> T newProxy(Class<T> interfaceClass, final MessageImpl messageImpl) {
+    ClassLoader classLoader = messageImpl.getClass().getClassLoader();
+    Class<?>[] interfaces = new Class<?>[] { interfaceClass, GetInstance.class };
+    MessageProxyInvocationHandler invocationHandler =
+        new MessageProxyInvocationHandler(messageImpl);
+    return (T) Proxy.newProxyInstance(classLoader, interfaces, invocationHandler);
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/MessageProxyInvocationHandler.java b/message_generator/src/main/java/org/ros/internal/message/MessageProxyInvocationHandler.java
new file mode 100644
index 0000000..2f1c2e2
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/MessageProxyInvocationHandler.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2012 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+import org.ros.internal.message.field.Field;
+import org.ros.internal.message.field.MessageFields;
+
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.Method;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class MessageProxyInvocationHandler implements InvocationHandler {
+
+  private final MessageImpl messageImpl;
+
+  MessageProxyInvocationHandler(MessageImpl messageImpl) {
+    this.messageImpl = messageImpl;
+  }
+
+  @Override
+  public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
+    String methodName = method.getName();
+    MessageFields mesageFields = messageImpl.getMessageFields();
+    Field getterField = mesageFields.getGetterField(methodName);
+    if (getterField != null) {
+      return getterField.getValue();
+    }
+    Field setterField = mesageFields.getSetterField(methodName);
+    if (setterField != null) {
+      setterField.setValue(args[0]);
+      return null;
+    }
+    return method.invoke(messageImpl, args);
+  }
+}
\ No newline at end of file
diff --git a/message_generator/src/main/java/org/ros/internal/message/RawMessage.java b/message_generator/src/main/java/org/ros/internal/message/RawMessage.java
new file mode 100644
index 0000000..999db7a
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/RawMessage.java
@@ -0,0 +1,207 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.ros.internal.message.field.Field;
+import org.ros.message.Duration;
+import org.ros.message.MessageIdentifier;
+import org.ros.message.Time;
+
+import java.util.List;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public interface RawMessage extends Message {
+
+  boolean getBool(String name);
+
+  boolean[] getBoolArray(String name);
+
+  /**
+   * @deprecated replaced by {@link #getInt8(String)}
+   */
+  byte getByte(String name);
+
+  /**
+   * @deprecated replaced by {@link #getInt8Array(String)}
+   */
+  byte[] getByteArray(String name);
+
+  /**
+   * @deprecated replaced by {@link #getUInt8(String)}
+   */
+  short getChar(String name);
+
+  /**
+   * @deprecated replaced by {@link #getUInt8Array(String)}
+   */
+  short[] getCharArray(String name);
+
+  String getDefinition();
+
+  Duration getDuration(String name);
+
+  List<Duration> getDurationList(String name);
+
+  List<Field> getFields();
+
+  float getFloat32(String name);
+
+  float[] getFloat32Array(String name);
+
+  double getFloat64(String name);
+
+  double[] getFloat64Array(String name);
+
+  MessageIdentifier getIdentifier();
+
+  short getInt16(String name);
+
+  short[] getInt16Array(String name);
+
+  int getInt32(String name);
+
+  int[] getInt32Array(String name);
+
+  long getInt64(String name);
+
+  long[] getInt64Array(String name);
+
+  byte getInt8(String name);
+
+  byte[] getInt8Array(String name);
+
+  <T extends Message> T getMessage(String name);
+
+  <T extends Message> List<T> getMessageList(String name);
+
+  String getName();
+
+  String getPackage();
+
+  String getString(String name);
+
+  List<String> getStringList(String name);
+
+  Time getTime(String name);
+
+  List<Time> getTimeList(String name);
+
+  String getType();
+
+  short getUInt16(String name);
+
+  short[] getUInt16Array(String name);
+
+  int getUInt32(String name);
+
+  int[] getUInt32Array(String name);
+
+  long getUInt64(String name);
+
+  long[] getUInt64Array(String name);
+
+  short getUInt8(String name);
+
+  short[] getUInt8Array(String name);
+
+  void setBool(String name, boolean value);
+
+  void setBoolArray(String name, boolean[] value);
+
+  /**
+   * @deprecated replaced by {@link #setInt8(String, byte)}
+   */
+  void setByte(String name, byte value);
+
+  /**
+   * @deprecated replaced by {@link #setInt8Array(String, byte[])}
+   */
+  void setByteArray(String name, byte[] value);
+
+  /**
+   * @deprecated replaced by {@link #setUInt8(String, byte)}
+   */
+  void setChar(String name, short value);
+
+  /**
+   * @deprecated replaced by {@link #setUInt8Array(String, byte[])}
+   */
+  void setCharArray(String name, short[] value);
+
+  void setDuration(String name, Duration value);
+
+  void setDurationList(String name, List<Duration> value);
+
+  void setFloat32(String name, float value);
+
+  void setFloat32Array(String name, float[] value);
+
+  void setFloat64(String name, double value);
+
+  void setFloat64Array(String name, double[] value);
+
+  void setInt16(String name, short value);
+
+  void setInt16Array(String name, short[] value);
+
+  void setInt32(String name, int value);
+
+  void setInt32Array(String name, int[] value);
+
+  void setInt64(String name, long value);
+
+  void setInt64Array(String name, long[] value);
+
+  void setInt8(String name, byte value);
+
+  void setInt8Array(String name, byte[] value);
+
+  void setMessage(String name, Message value);
+
+  void setMessageList(String name, List<Message> value);
+
+  void setString(String name, String value);
+
+  void setStringList(String name, List<String> value);
+
+  void setTime(String name, Time value);
+
+  void setTimeList(String name, List<Time> value);
+
+  void setUInt16(String name, short value);
+
+  void setUInt16Array(String name, short[] value);
+
+  void setUInt32(String name, int value);
+
+  void setUInt32Array(String name, int[] value);
+
+  void setUInt64(String name, long value);
+
+  void setUInt64Array(String name, long[] value);
+
+  void setUInt8(String name, byte value);
+
+  void setUInt8Array(String name, byte[] value);
+
+  void setChannelBuffer(String name, ChannelBuffer value);
+
+  ChannelBuffer getChannelBuffer(String name);
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/StringFileProvider.java b/message_generator/src/main/java/org/ros/internal/message/StringFileProvider.java
new file mode 100644
index 0000000..2f9ddfa
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/StringFileProvider.java
@@ -0,0 +1,130 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
+
+import org.apache.commons.io.DirectoryWalker;
+import org.apache.commons.io.FileUtils;
+import org.apache.commons.io.filefilter.FileFilterUtils;
+import org.apache.commons.io.filefilter.IOFileFilter;
+import org.ros.exception.RosMessageRuntimeException;
+
+import java.io.File;
+import java.io.FileFilter;
+import java.io.IOException;
+import java.util.Collection;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class StringFileProvider {
+
+  private final Collection<File> directories;
+  private final Map<File, String> strings;
+  private final StringFileDirectoryWalker stringFileDirectoryWalker;
+
+  private final class StringFileDirectoryWalker extends DirectoryWalker {
+    
+    private final Set<File> directories;
+
+    private StringFileDirectoryWalker(FileFilter filter, int depthLimit) {
+      super(filter, depthLimit);
+      directories = Sets.newHashSet();
+    }
+    
+    // TODO(damonkohler): Update Apache Commons IO to the latest version.
+    @SuppressWarnings("rawtypes")
+    @Override
+    protected boolean handleDirectory(File directory, int depth, Collection results)
+        throws IOException {
+      File canonicalDirectory = directory.getCanonicalFile();
+      if (directories.contains(canonicalDirectory)) {
+        return false;
+      }
+      directories.add(canonicalDirectory);
+      return true;
+    }
+
+    @SuppressWarnings("rawtypes")
+    @Override
+    protected void handleFile(File file, int depth, Collection results) {
+      String content;
+      try {
+        content = FileUtils.readFileToString(file, "US-ASCII");
+      } catch (IOException e) {
+        throw new RosMessageRuntimeException(e);
+      }
+      strings.put(file, content);
+    }
+
+    public void update(File directory) {
+      try {
+        walk(directory, null);
+      } catch (IOException e) {
+        throw new RosMessageRuntimeException(e);
+      }
+    }
+  }
+
+  public StringFileProvider(IOFileFilter ioFileFilter) {
+    directories = Lists.newArrayList();
+    strings = Maps.newConcurrentMap();
+    IOFileFilter directoryFilter = FileFilterUtils.directoryFileFilter();
+    FileFilter fileFilter = FileFilterUtils.orFileFilter(directoryFilter, ioFileFilter);
+    stringFileDirectoryWalker = new StringFileDirectoryWalker(fileFilter, -1);
+  }
+
+  public void update() {
+    for (File directory : directories) {
+      stringFileDirectoryWalker.update(directory);
+    }
+  }
+
+  /**
+   * Adds a new directory to be scanned for topic definition files.
+   * 
+   * @param directory
+   *          the directory to add
+   */
+  public void addDirectory(File directory) {
+    Preconditions.checkArgument(directory.isDirectory());
+    directories.add(directory);
+  }
+
+  public Map<File, String> getStrings() {
+    return ImmutableMap.copyOf(strings);
+  }
+
+  public String get(File file) {
+    if (!has(file)) {
+      throw new NoSuchElementException("File does not exist: " + file);
+    }
+    return strings.get(file);
+  }
+
+  public boolean has(File file) {
+    return strings.containsKey(file);
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/StringResourceProvider.java b/message_generator/src/main/java/org/ros/internal/message/StringResourceProvider.java
new file mode 100644
index 0000000..c7de05f
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/StringResourceProvider.java
@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Maps;
+
+import org.ros.exception.RosMessageRuntimeException;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.charset.Charset;
+import java.util.Map;
+import java.util.NoSuchElementException;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class StringResourceProvider {
+
+  private final Map<String, String> cache;
+
+  public StringResourceProvider() {
+    cache = Maps.newConcurrentMap();
+  }
+
+  public String get(String resourceName) {
+    if (!has(resourceName)) {
+      throw new NoSuchElementException("Resource does not exist: " + resourceName);
+    }
+    if (!cache.containsKey(resourceName)) {
+      InputStream in = getClass().getResourceAsStream(resourceName);
+      StringBuilder out = new StringBuilder();
+      Charset charset = Charset.forName("US-ASCII");
+      byte[] buffer = new byte[8192];
+      try {
+        for (int bytesRead; (bytesRead = in.read(buffer)) != -1;) {
+          out.append(new String(buffer, 0, bytesRead, charset));
+        }
+      } catch (IOException e) {
+        throw new RosMessageRuntimeException("Failed to read resource: " + resourceName, e);
+      }
+      cache.put(resourceName, out.toString());
+    }
+    return cache.get(resourceName);
+  }
+
+  public boolean has(String resourceName) {
+    return cache.containsKey(resourceName) || getClass().getResource(resourceName) != null;
+  }
+
+  public Map<String, String> getCachedStrings() {
+    return ImmutableMap.copyOf(cache);
+  }
+
+  public void addStringToCache(String resourceName, String resourceContent) {
+    cache.put(resourceName, resourceContent);
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/context/MessageContext.java b/message_generator/src/main/java/org/ros/internal/message/context/MessageContext.java
new file mode 100644
index 0000000..11f4a2b
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/context/MessageContext.java
@@ -0,0 +1,144 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.context;
+
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
+
+import org.ros.internal.message.field.FieldFactory;
+import org.ros.message.MessageDeclaration;
+import org.ros.message.MessageFactory;
+import org.ros.message.MessageIdentifier;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Encapsulates the immutable metadata that describes a message type.
+ * <p>
+ * Note that this class is not thread safe.
+ * 
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class MessageContext {
+
+  private final MessageDeclaration messageDeclaration;
+  private final MessageFactory messageFactory;
+  private final Map<String, FieldFactory> fieldFactories;
+  private final Map<String, String> fieldGetterNames;
+  private final Map<String, String> fieldSetterNames;
+  private final List<String> fieldNames;
+
+  public MessageContext(MessageDeclaration messageDeclaration, MessageFactory messageFactory) {
+    this.messageDeclaration = messageDeclaration;
+    this.messageFactory = messageFactory;
+    this.fieldFactories = Maps.newHashMap();
+    this.fieldGetterNames = Maps.newHashMap();
+    this.fieldSetterNames = Maps.newHashMap();
+    this.fieldNames = Lists.newArrayList();
+  }
+
+  public MessageFactory getMessageFactory() {
+    return messageFactory;
+  }
+
+  public MessageIdentifier getMessageIdentifer() {
+    return messageDeclaration.getMessageIdentifier();
+  }
+
+  public String getType() {
+    return messageDeclaration.getType();
+  }
+
+  public String getPackage() {
+    return messageDeclaration.getPackage();
+  }
+
+  public String getName() {
+    return messageDeclaration.getName();
+  }
+
+  public String getDefinition() {
+    return messageDeclaration.getDefinition();
+  }
+
+  public void addFieldFactory(String name, FieldFactory fieldFactory) {
+    fieldFactories.put(name, fieldFactory);
+    fieldGetterNames.put(name, "get" + getJavaName(name));
+    fieldSetterNames.put(name, "set" + getJavaName(name));
+    fieldNames.add(name);
+  }
+
+  private String getJavaName(String name) {
+    String[] parts = name.split("_");
+    StringBuilder fieldName = new StringBuilder();
+    for (String part : parts) {
+      fieldName.append(part.substring(0, 1).toUpperCase() + part.substring(1));
+    }
+    return fieldName.toString();
+  }
+
+  public boolean hasField(String name) {
+    // O(1) instead of an O(n) check against the list of field names.
+    return fieldFactories.containsKey(name);
+  }
+
+  public String getFieldGetterName(String name) {
+    return fieldGetterNames.get(name);
+  }
+
+  public String getFieldSetterName(String name) {
+    return fieldSetterNames.get(name);
+  }
+
+  public FieldFactory getFieldFactory(String name) {
+    return fieldFactories.get(name);
+  }
+
+  /**
+   * @return a {@link List} of field names in the order they were added
+   */
+  public List<String> getFieldNames() {
+    return Collections.unmodifiableList(fieldNames);
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = 1;
+    result = prime * result + ((messageDeclaration == null) ? 0 : messageDeclaration.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (obj == null)
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    MessageContext other = (MessageContext) obj;
+    if (messageDeclaration == null) {
+      if (other.messageDeclaration != null)
+        return false;
+    } else if (!messageDeclaration.equals(other.messageDeclaration))
+      return false;
+    return true;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/context/MessageContextBuilder.java b/message_generator/src/main/java/org/ros/internal/message/context/MessageContextBuilder.java
new file mode 100644
index 0000000..dd14924
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/context/MessageContextBuilder.java
@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.context;
+
+import com.google.common.base.Preconditions;
+
+import org.ros.internal.message.definition.MessageDefinitionParser.MessageDefinitionVisitor;
+import org.ros.internal.message.field.Field;
+import org.ros.internal.message.field.FieldFactory;
+import org.ros.internal.message.field.FieldType;
+import org.ros.internal.message.field.MessageFieldType;
+import org.ros.internal.message.field.PrimitiveFieldType;
+import org.ros.message.MessageIdentifier;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+class MessageContextBuilder implements MessageDefinitionVisitor {
+
+  private final MessageContext messageContext;
+
+  public MessageContextBuilder(MessageContext context) {
+    this.messageContext = context;
+  }
+
+  private FieldType getFieldType(String type) {
+    Preconditions.checkArgument(!type.equals(messageContext.getType()),
+        "Message definitions may not be self-referential.");
+    FieldType fieldType;
+    if (PrimitiveFieldType.existsFor(type)) {
+      fieldType = PrimitiveFieldType.valueOf(type.toUpperCase());
+    } else {
+      fieldType =
+          new MessageFieldType(MessageIdentifier.of(type), messageContext.getMessageFactory());
+    }
+    return fieldType;
+  }
+
+  @Override
+  public void variableValue(String type, final String name) {
+    final FieldType fieldType = getFieldType(type);
+    messageContext.addFieldFactory(name, new FieldFactory() {
+      @Override
+      public Field create() {
+        return fieldType.newVariableValue(name);
+      }
+    });
+  }
+
+  @Override
+  public void variableList(String type, final int size, final String name) {
+    final FieldType fieldType = getFieldType(type);
+    messageContext.addFieldFactory(name, new FieldFactory() {
+      @Override
+      public Field create() {
+        return fieldType.newVariableList(name, size);
+      }
+    });
+  }
+
+  @Override
+  public void constantValue(String type, final String name, final String value) {
+    final FieldType fieldType = getFieldType(type);
+    messageContext.addFieldFactory(name, new FieldFactory() {
+      @Override
+      public Field create() {
+        return fieldType.newConstantValue(name, fieldType.parseFromString(value));
+      }
+    });
+  }
+}
\ No newline at end of file
diff --git a/message_generator/src/main/java/org/ros/internal/message/context/MessageContextProvider.java b/message_generator/src/main/java/org/ros/internal/message/context/MessageContextProvider.java
new file mode 100644
index 0000000..0782970
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/context/MessageContextProvider.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.context;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.Maps;
+
+import org.ros.internal.message.definition.MessageDefinitionParser;
+import org.ros.internal.message.definition.MessageDefinitionParser.MessageDefinitionVisitor;
+import org.ros.message.MessageDeclaration;
+import org.ros.message.MessageFactory;
+
+import java.util.Map;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class MessageContextProvider {
+
+  private final Map<MessageDeclaration, MessageContext> cache;
+  private final MessageFactory messageFactory;
+
+  public MessageContextProvider(MessageFactory messageFactory) {
+    Preconditions.checkNotNull(messageFactory);
+    this.messageFactory = messageFactory;
+    cache = Maps.newConcurrentMap();
+  }
+
+  public MessageContext get(MessageDeclaration messageDeclaration) {
+    MessageContext messageContext = cache.get(messageDeclaration);
+    if (messageContext == null) {
+      messageContext = new MessageContext(messageDeclaration, messageFactory);
+      MessageDefinitionVisitor visitor = new MessageContextBuilder(messageContext);
+      MessageDefinitionParser messageDefinitionParser = new MessageDefinitionParser(visitor);
+      messageDefinitionParser.parse(messageDeclaration.getType(),
+          messageDeclaration.getDefinition());
+      cache.put(messageDeclaration, messageContext);
+    }
+    return messageContext;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionFileProvider.java b/message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionFileProvider.java
new file mode 100644
index 0000000..4aa0389
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionFileProvider.java
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.definition;
+
+import com.google.common.collect.Maps;
+
+import org.ros.internal.message.StringFileProvider;
+
+import org.apache.commons.io.FilenameUtils;
+import org.ros.message.MessageDefinitionProvider;
+import org.ros.message.MessageIdentifier;
+
+import java.io.File;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Map.Entry;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class MessageDefinitionFileProvider implements MessageDefinitionProvider {
+
+  private final StringFileProvider stringFileProvider;
+  private final Map<String, Collection<MessageIdentifier>> messageIdentifiers;
+  private final Map<String, String> definitions;
+
+  public MessageDefinitionFileProvider(StringFileProvider stringFileProvider) {
+    this.stringFileProvider = stringFileProvider;
+    messageIdentifiers = Maps.newConcurrentMap();
+    definitions = Maps.newConcurrentMap();
+  }
+
+  private static String getParent(String filename) {
+    return FilenameUtils.getFullPathNoEndSeparator(filename);
+  }
+
+  protected static String getParentBaseName(String filename) {
+    return FilenameUtils.getBaseName(getParent(filename));
+  }
+
+  private static MessageIdentifier fileToMessageIdentifier(File file) {
+    String filename = file.getAbsolutePath();
+    String name = FilenameUtils.getBaseName(filename);
+    String pkg = getParentBaseName(getParent(filename));
+    return MessageIdentifier.of(pkg, name);
+  }
+
+  private void addDefinition(File file, String definition) {
+    MessageIdentifier topicType = fileToMessageIdentifier(file);
+    if (definitions.containsKey(topicType.getType())) {
+      // First definition wins.
+      return;
+    }
+    definitions.put(topicType.getType(), definition);
+    if (!messageIdentifiers.containsKey(topicType.getPackage())) {
+      messageIdentifiers.put(topicType.getPackage(), new HashSet<MessageIdentifier>());
+    }
+    messageIdentifiers.get(topicType.getPackage()).add(topicType);
+  }
+
+  /**
+   * Updates the topic definition cache.
+   * 
+   * @see StringFileProvider#update()
+   */
+  public void update() {
+    stringFileProvider.update();
+    for (Entry<File, String> entry : stringFileProvider.getStrings().entrySet()) {
+      addDefinition(entry.getKey(), entry.getValue());
+    }
+  }
+
+  /**
+   * @see StringFileProvider#addDirectory(File)
+   */
+  public void addDirectory(File directory) {
+    stringFileProvider.addDirectory(directory);
+  }
+
+  @Override
+  public Collection<String> getPackages() {
+    return messageIdentifiers.keySet();
+  }
+
+  @Override
+  public Collection<MessageIdentifier> getMessageIdentifiersByPackage(String pkg) {
+    return messageIdentifiers.get(pkg);
+  }
+
+  @Override
+  public String get(String type) {
+    return definitions.get(type);
+  }
+
+  @Override
+  public boolean has(String type) {
+    return definitions.containsKey(type);
+  }
+}
\ No newline at end of file
diff --git a/message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionParser.java b/message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionParser.java
new file mode 100644
index 0000000..e0bbe1e
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionParser.java
@@ -0,0 +1,176 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.definition;
+
+import com.google.common.base.Preconditions;
+
+import org.ros.exception.RosMessageRuntimeException;
+import org.ros.internal.message.field.PrimitiveFieldType;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.StringReader;
+
+/**
+ * Parses message definitions and invokes a {@link MessageDefinitionVisitor} for
+ * each field.
+ * 
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class MessageDefinitionParser {
+
+  private final MessageDefinitionVisitor visitor;
+
+  public interface MessageDefinitionVisitor {
+    /**
+     * Called for each constant in the message definition.
+     * 
+     * @param type
+     *          the type of the constant
+     * @param name
+     *          the name of the constant
+     * @param value
+     *          the value of the constant
+     */
+    void constantValue(String type, String name, String value);
+
+    /**
+     * Called for each scalar in the message definition.
+     * 
+     * @param type
+     *          the type of the scalar
+     * @param name
+     *          the name of the scalar
+     */
+    void variableValue(String type, String name);
+
+    /**
+     * Called for each array in the message definition.
+     * 
+     * @param type
+     *          the type of the array
+     * @param size
+     *          the size of the array or -1 if the size is unbounded
+     * @param name
+     *          the name of the array
+     */
+    void variableList(String type, int size, String name);
+  }
+
+  /**
+   * @param visitor
+   *          the {@link MessageDefinitionVisitor} that will be called for each
+   *          field
+   */
+  public MessageDefinitionParser(MessageDefinitionVisitor visitor) {
+    this.visitor = visitor;
+  }
+
+  /**
+   * Parses the message definition
+   * 
+   * @param messageType
+   *          the type of message defined (e.g. std_msgs/String)
+   * @param messageDefinition
+   *          the message definition (e.g. "string data")
+   */
+  public void parse(String messageType, String messageDefinition) {
+    Preconditions.checkNotNull(messageType);
+    Preconditions.checkNotNull(messageDefinition);
+    BufferedReader reader = new BufferedReader(new StringReader(messageDefinition));
+    String line;
+    try {
+      while (true) {
+        line = reader.readLine();
+        if (line == null) {
+          break;
+        }
+        line = line.trim();
+        if (line.startsWith("#")) {
+          continue;
+        }
+        if (line.length() > 0) {
+          parseField(messageType, line);
+        }
+      }
+    } catch (IOException e) {
+      throw new RosMessageRuntimeException(e);
+    }
+  }
+
+  private void parseField(String messageType, String fieldDefinition) {
+    // TODO(damonkohler): Regex input validation.
+    String[] typeAndName = fieldDefinition.split("\\s+", 2);
+    Preconditions.checkState(typeAndName.length == 2,
+        String.format("Invalid field definition: \"%s\"", fieldDefinition));
+    String type = typeAndName[0];
+    String name = typeAndName[1];
+    String value = null;
+    if (name.contains("=") && (!name.contains("#") || name.indexOf('#') > name.indexOf('='))) {
+      String[] nameAndValue = name.split("=", 2);
+      name = nameAndValue[0].trim();
+      value = nameAndValue[1].trim();
+    } else if (name.contains("#")) {
+      // Stripping comments from constants is deferred until we also know the
+      // type since strings are handled differently.
+      Preconditions.checkState(!name.startsWith("#"), String.format(
+          "Fields must define a name. Field definition in %s was: \"%s\"", messageType,
+          fieldDefinition));
+      name = name.substring(0, name.indexOf('#'));
+      name = name.trim();
+    }
+    boolean array = false;
+    int size = -1;
+    if (type.endsWith("]")) {
+      int leftBracketIndex = type.lastIndexOf('[');
+      int rightBracketIndex = type.lastIndexOf(']');
+      array = true;
+      if (rightBracketIndex - leftBracketIndex > 1) {
+        size = Integer.parseInt(type.substring(leftBracketIndex + 1, rightBracketIndex));
+      }
+      type = type.substring(0, leftBracketIndex);
+    }
+    if (type.equals("Header")) {
+      // The header field is treated as though it were a built-in and silently
+      // expanded to "std_msgs/Header."
+      Preconditions.checkState(name.equals("header"), "Header field must be named \"header.\"");
+      type = "std_msgs/Header";
+    } else if (!PrimitiveFieldType.existsFor(type) && !type.contains("/")) {
+      // Handle package relative message names.
+      type = messageType.substring(0, messageType.lastIndexOf('/') + 1) + type;
+    }
+    if (value != null) {
+      if (array) {
+        // TODO(damonkohler): Handle array constants?
+        throw new UnsupportedOperationException("Array constants are not supported.");
+      }
+      // Comments inline with string constants are treated as data.
+      if (!type.equals(PrimitiveFieldType.STRING.getName()) && value.contains("#")) {
+        Preconditions.checkState(!value.startsWith("#"), "Constants must define a value.");
+        value = value.substring(0, value.indexOf('#'));
+        value = value.trim();
+      }
+      visitor.constantValue(type, name, value);
+    } else {
+      if (array) {
+        visitor.variableList(type, size, name);
+      } else {
+        visitor.variableValue(type, name);
+      }
+    }
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionProviderChain.java b/message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionProviderChain.java
new file mode 100644
index 0000000..9bf71de
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionProviderChain.java
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.definition;
+
+import com.google.common.collect.Lists;
+import com.google.common.collect.Sets;
+
+import org.ros.message.MessageDefinitionProvider;
+import org.ros.message.MessageIdentifier;
+
+import java.util.Collection;
+import java.util.NoSuchElementException;
+import java.util.Set;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class MessageDefinitionProviderChain implements MessageDefinitionProvider {
+
+  private final Collection<MessageDefinitionProvider> messageDefinitionProviders;
+
+  public MessageDefinitionProviderChain() {
+    messageDefinitionProviders = Lists.newArrayList();
+  }
+
+  public void addMessageDefinitionProvider(MessageDefinitionProvider messageDefinitionProvider) {
+    messageDefinitionProviders.add(messageDefinitionProvider);
+  }
+
+  @Override
+  public String get(String messageType) {
+    for (MessageDefinitionProvider messageDefinitionProvider : messageDefinitionProviders) {
+      if (messageDefinitionProvider.has(messageType)) {
+        return messageDefinitionProvider.get(messageType);
+      }
+    }
+    throw new NoSuchElementException("No message definition available for: " + messageType);
+  }
+
+  @Override
+  public boolean has(String messageType) {
+    for (MessageDefinitionProvider messageDefinitionProvider : messageDefinitionProviders) {
+      if (messageDefinitionProvider.has(messageType)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  @Override
+  public Collection<String> getPackages() {
+    Set<String> result = Sets.newHashSet();
+    for (MessageDefinitionProvider messageDefinitionProvider : messageDefinitionProviders) {
+      Collection<String> packages = messageDefinitionProvider.getPackages();
+      result.addAll(packages);
+    }
+    return result;
+  }
+
+  @Override
+  public Collection<MessageIdentifier> getMessageIdentifiersByPackage(String pkg) {
+    Set<MessageIdentifier> result = Sets.newHashSet();
+    for (MessageDefinitionProvider messageDefinitionProvider : messageDefinitionProviders) {
+      Collection<MessageIdentifier> messageIdentifiers =
+          messageDefinitionProvider.getMessageIdentifiersByPackage(pkg);
+      if (messageIdentifiers != null) {
+        result.addAll(messageIdentifiers);
+      }
+    }
+    return result;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionReflectionProvider.java b/message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionReflectionProvider.java
new file mode 100644
index 0000000..6a5097e
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionReflectionProvider.java
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.definition;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.collect.Maps;
+
+import org.ros.exception.RosMessageRuntimeException;
+import org.ros.message.MessageDefinitionProvider;
+import org.ros.message.MessageIdentifier;
+
+import java.util.Collection;
+import java.util.Map;
+
+/**
+ * A {@link MessageDefinitionProvider} that uses reflection to load the message
+ * definition {@link String} from a generated interface {@link Class}.
+ * <p>
+ * Note that this {@link MessageDefinitionProvider} does not support enumerating
+ * messages by package.
+ * 
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class MessageDefinitionReflectionProvider implements MessageDefinitionProvider {
+
+  private static final String DEFINITION_FIELD = "_DEFINITION";
+
+  private final Map<String, String> cache;
+
+  public MessageDefinitionReflectionProvider() {
+    cache = Maps.newConcurrentMap();
+  }
+
+  @Override
+  public String get(String messageType) {
+    String messageDefinition = cache.get(messageType);
+    if (messageDefinition == null) {
+      String className = messageType.replace("/", ".");
+      try {
+        Class<?> loadedClass = getClass().getClassLoader().loadClass(className);
+        messageDefinition = (String) loadedClass.getDeclaredField(DEFINITION_FIELD).get(null);
+        cache.put(messageType, messageDefinition);
+      } catch (Exception e) {
+        throw new RosMessageRuntimeException(e);
+      }
+    }
+    return messageDefinition;
+  }
+
+  @Override
+  public boolean has(String messageType) {
+    try {
+      get(messageType);
+    } catch (Exception e) {
+      return false;
+    }
+    return true;
+  }
+
+  @Override
+  public Collection<String> getPackages() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public Collection<MessageIdentifier> getMessageIdentifiersByPackage(String pkg) {
+    throw new UnsupportedOperationException();
+  }
+
+  @VisibleForTesting
+  public void add(String messageType, String messageDefinition) {
+    cache.put(messageType, messageDefinition);
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionTupleParser.java b/message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionTupleParser.java
new file mode 100644
index 0000000..e7cdc9f
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/definition/MessageDefinitionTupleParser.java
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.definition;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.Lists;
+
+import java.util.List;
+
+/**
+ * Splits message definitions tuples (e.g. service definitions) into separate
+ * message definitions.
+ * 
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class MessageDefinitionTupleParser {
+
+  private static final String SEPARATOR = "---";
+
+  /**
+   * Splits the message definition tuple into a {@link List} of message
+   * definitions. Split message definitions may be empty (e.g. std_srvs/Empty).
+   * 
+   * @param definition
+   *          the message definition tuple
+   * @param size
+   *          the expected tuple size, or -1 to ignore this requirement
+   * @return a {@link List} of the specified size
+   */
+  public static List<String> parse(String definition, int size) {
+    Preconditions.checkNotNull(definition);
+    List<String> definitions = Lists.newArrayList();
+    StringBuilder current = new StringBuilder();
+    for (String line : definition.split("\n")) {
+      if (line.startsWith(SEPARATOR)) {
+        definitions.add(current.toString());
+        current = new StringBuilder();
+        continue;
+      }
+      current.append(line);
+      current.append("\n");
+    }
+    if (current.length() > 0) {
+      current.deleteCharAt(current.length() - 1);
+    }
+    definitions.add(current.toString());
+    Preconditions.checkState(size == -1 || definitions.size() <= size,
+        String.format("Message tuple exceeds expected size: %d > %d", definitions.size(), size));
+    while (definitions.size() < size) {
+      definitions.add("");
+    }
+    return definitions;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/field/BooleanArrayField.java b/message_generator/src/main/java/org/ros/internal/message/field/BooleanArrayField.java
new file mode 100644
index 0000000..75a9fe1
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/field/BooleanArrayField.java
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.field;
+
+import com.google.common.base.Preconditions;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+
+import java.util.Arrays;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class BooleanArrayField extends Field {
+
+  private final int size;
+
+  private boolean[] value;
+
+  public static BooleanArrayField newVariable(String name, int size) {
+    return new BooleanArrayField(PrimitiveFieldType.BOOL, name, size);
+  }
+
+  private BooleanArrayField(FieldType type, String name, int size) {
+    super(type, name, false);
+    this.size = size;
+    setValue(new boolean[Math.max(0, size)]);
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public boolean[] getValue() {
+    return value;
+  }
+
+  @Override
+  public void setValue(Object value) {
+    Preconditions.checkArgument(size < 0 || ((boolean[]) value).length == size);
+    this.value = (boolean[]) value;
+  }
+
+  @Override
+  public void serialize(ChannelBuffer buffer) {
+    if (size < 0) {
+      buffer.writeInt(value.length);
+    }
+    for (boolean v : value) {
+      type.serialize(v, buffer);
+    }
+  }
+
+  @Override
+  public void deserialize(ChannelBuffer buffer) {
+    int currentSize = size;
+    if (currentSize < 0) {
+      currentSize = buffer.readInt();
+    }
+    value = new boolean[currentSize];
+    for (int i = 0; i < currentSize; i++) {
+      value[i] = buffer.readByte() == 1;
+    }
+  }
+
+  @Override
+  public String getMd5String() {
+    return String.format("%s %s\n", type, name);
+  }
+
+  @Override
+  public String getJavaTypeName() {
+    return type.getJavaTypeName() + "[]";
+  }
+
+  @Override
+  public String toString() {
+    return "BooleanArrayField<" + type + ", " + name + ">";
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = super.hashCode();
+    result = prime * result + ((value == null) ? 0 : value.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (!super.equals(obj))
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    BooleanArrayField other = (BooleanArrayField) obj;
+    if (value == null) {
+      if (other.value != null)
+        return false;
+    } else if (!Arrays.equals(value, other.value))
+      return false;
+    return true;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/field/ByteArrayField.java b/message_generator/src/main/java/org/ros/internal/message/field/ByteArrayField.java
new file mode 100644
index 0000000..02e08bf
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/field/ByteArrayField.java
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.field;
+
+import com.google.common.base.Preconditions;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+
+import java.util.Arrays;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class ByteArrayField extends Field {
+
+  private final int size;
+
+  private byte[] value;
+
+  public static ByteArrayField newVariable(FieldType type, String name, int size) {
+    return new ByteArrayField(type, name, size);
+  }
+
+  private ByteArrayField(FieldType type, String name, int size) {
+    super(type, name, false);
+    this.size = size;
+    setValue(new byte[Math.max(0, size)]);
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public byte[] getValue() {
+    return value;
+  }
+
+  @Override
+  public void setValue(Object value) {
+    Preconditions.checkArgument(size < 0 || ((byte[]) value).length == size);
+    this.value = (byte[]) value;
+  }
+
+  @Override
+  public void serialize(ChannelBuffer buffer) {
+    if (size < 0) {
+      buffer.writeInt(value.length);
+    }
+    for (byte v : value) {
+      type.serialize(v, buffer);
+    }
+  }
+
+  @Override
+  public void deserialize(ChannelBuffer buffer) {
+    int currentSize = size;
+    if (currentSize < 0) {
+      currentSize = buffer.readInt();
+    }
+    value = new byte[currentSize];
+    for (int i = 0; i < currentSize; i++) {
+      value[i] = buffer.readByte();
+    }
+  }
+
+  @Override
+  public String getMd5String() {
+    return String.format("%s %s\n", type, name);
+  }
+
+  @Override
+  public String getJavaTypeName() {
+    return type.getJavaTypeName() + "[]";
+  }
+
+  @Override
+  public String toString() {
+    return "ByteArrayField<" + type + ", " + name + ">";
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = super.hashCode();
+    result = prime * result + ((value == null) ? 0 : value.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (!super.equals(obj))
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    ByteArrayField other = (ByteArrayField) obj;
+    if (value == null) {
+      if (other.value != null)
+        return false;
+    } else if (!Arrays.equals(value, other.value))
+      return false;
+    return true;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/field/ChannelBufferField.java b/message_generator/src/main/java/org/ros/internal/message/field/ChannelBufferField.java
new file mode 100644
index 0000000..a13f542
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/field/ChannelBufferField.java
@@ -0,0 +1,118 @@
+/*
+ * Copyright (C) 2012 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.field;
+
+import com.google.common.base.Preconditions;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.ros.internal.message.MessageBuffers;
+
+import java.nio.ByteOrder;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class ChannelBufferField extends Field {
+
+  private final int size;
+
+  private ChannelBuffer value;
+
+  public static ChannelBufferField newVariable(FieldType type, String name, int size) {
+    return new ChannelBufferField(type, name, size);
+  }
+
+  private ChannelBufferField(FieldType type, String name, int size) {
+    super(type, name, false);
+    this.size = size;
+    value = MessageBuffers.dynamicBuffer();
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public ChannelBuffer getValue() {
+    // Return a defensive duplicate. Unlike with copy(), duplicated
+    // ChannelBuffers share the same backing array, so this is relatively cheap.
+    return value.duplicate();
+  }
+
+  @Override
+  public void setValue(Object value) {
+    Preconditions.checkArgument(((ChannelBuffer) value).order() == ByteOrder.LITTLE_ENDIAN);
+    Preconditions.checkArgument(size < 0 || ((ChannelBuffer) value).readableBytes() == size);
+    this.value = (ChannelBuffer) value;
+  }
+
+  @Override
+  public void serialize(ChannelBuffer buffer) {
+    if (size < 0) {
+      buffer.writeInt(value.readableBytes());
+    }
+    // By specifying the start index and length we avoid modifying value's
+    // indices and marks.
+    buffer.writeBytes(value, 0, value.readableBytes());
+  }
+
+  @Override
+  public void deserialize(ChannelBuffer buffer) {
+    int currentSize = size;
+    if (currentSize < 0) {
+      currentSize = buffer.readInt();
+    }
+    value = buffer.readSlice(currentSize);
+  }
+
+  @Override
+  public String getMd5String() {
+    return String.format("%s %s\n", type, name);
+  }
+
+  @Override
+  public String getJavaTypeName() {
+    return "org.jboss.netty.buffer.ChannelBuffer";
+  }
+
+  @Override
+  public String toString() {
+    return "ChannelBufferField<" + type + ", " + name + ">";
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = super.hashCode();
+    result = prime * result + ((value == null) ? 0 : value.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (!super.equals(obj))
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    ChannelBufferField other = (ChannelBufferField) obj;
+    if (value == null) {
+      if (other.value != null)
+        return false;
+    } else if (!value.equals(other.value))
+      return false;
+    return true;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/field/DoubleArrayField.java b/message_generator/src/main/java/org/ros/internal/message/field/DoubleArrayField.java
new file mode 100644
index 0000000..a0c3945
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/field/DoubleArrayField.java
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.field;
+
+import com.google.common.base.Preconditions;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+
+import java.util.Arrays;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class DoubleArrayField extends Field {
+
+  private final int size;
+
+  private double[] value;
+
+  public static DoubleArrayField newVariable(String name, int size) {
+    return new DoubleArrayField(PrimitiveFieldType.FLOAT64, name, size);
+  }
+
+  private DoubleArrayField(FieldType type, String name, int size) {
+    super(type, name, false);
+    this.size = size;
+    setValue(new double[Math.max(0, size)]);
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public double[] getValue() {
+    return value;
+  }
+
+  @Override
+  public void setValue(Object value) {
+    Preconditions.checkArgument(size < 0 || ((double[]) value).length == size);
+    this.value = (double[]) value;
+  }
+
+  @Override
+  public void serialize(ChannelBuffer buffer) {
+    if (size < 0) {
+      buffer.writeInt(value.length);
+    }
+    for (double v : value) {
+      type.serialize(v, buffer);
+    }
+  }
+
+  @Override
+  public void deserialize(ChannelBuffer buffer) {
+    int currentSize = size;
+    if (currentSize < 0) {
+      currentSize = buffer.readInt();
+    }
+    value = new double[currentSize];
+    for (int i = 0; i < currentSize; i++) {
+      value[i] = buffer.readDouble();
+    }
+  }
+
+  @Override
+  public String getMd5String() {
+    return String.format("%s %s\n", type, name);
+  }
+
+  @Override
+  public String getJavaTypeName() {
+    return type.getJavaTypeName() + "[]";
+  }
+
+  @Override
+  public String toString() {
+    return "DoubleArrayField<" + type + ", " + name + ">";
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = super.hashCode();
+    result = prime * result + ((value == null) ? 0 : value.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (!super.equals(obj))
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    DoubleArrayField other = (DoubleArrayField) obj;
+    if (value == null) {
+      if (other.value != null)
+        return false;
+    } else if (!Arrays.equals(value, other.value))
+      return false;
+    return true;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/field/Field.java b/message_generator/src/main/java/org/ros/internal/message/field/Field.java
new file mode 100644
index 0000000..d714dfc
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/field/Field.java
@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.field;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public abstract class Field {
+
+  protected final FieldType type;
+  protected final String name;
+  protected final boolean isConstant;
+
+  protected Field(FieldType type, String name, boolean isConstant) {
+    this.name = name;
+    this.type = type;
+    this.isConstant = isConstant;
+  }
+
+  /**
+   * @return the name
+   */
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * @return the type
+   */
+  public FieldType getType() {
+    return type;
+  }
+
+  /**
+   * @return <code>true</code> if this {@link ListField} represents a constant
+   */
+  public boolean isConstant() {
+    return isConstant;
+  }
+
+  /**
+   * @return the textual representation of this field used for computing the MD5
+   *         of a message definition
+   */
+  public String getMd5String() {
+    if (isConstant()) {
+      return String.format("%s %s=%s\n", getType().getMd5String(), getName(), getValue());
+    }
+    return String.format("%s %s\n", getType().getMd5String(), getName());
+  }
+
+  public abstract void serialize(ChannelBuffer buffer);
+
+  public abstract void deserialize(ChannelBuffer buffer);
+
+  public abstract <T> T getValue();
+
+  // TODO(damonkohler): Why not make Field generic?
+  public abstract void setValue(Object value);
+
+  public abstract String getJavaTypeName();
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = 1;
+    result = prime * result + (isConstant ? 1231 : 1237);
+    result = prime * result + ((name == null) ? 0 : name.hashCode());
+    result = prime * result + ((type == null) ? 0 : type.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (obj == null)
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    Field other = (Field) obj;
+    if (isConstant != other.isConstant)
+      return false;
+    if (name == null) {
+      if (other.name != null)
+        return false;
+    } else if (!name.equals(other.name))
+      return false;
+    if (type == null) {
+      if (other.type != null)
+        return false;
+    } else if (!type.equals(other.type))
+      return false;
+    return true;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/field/FieldFactory.java b/message_generator/src/main/java/org/ros/internal/message/field/FieldFactory.java
new file mode 100644
index 0000000..24b3053
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/field/FieldFactory.java
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.field;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public interface FieldFactory {
+
+  Field create();
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/field/FieldType.java b/message_generator/src/main/java/org/ros/internal/message/field/FieldType.java
new file mode 100644
index 0000000..b227b4d
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/field/FieldType.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.field;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public interface FieldType {
+
+  public <T> T getDefaultValue();
+
+  public String getName();
+
+  public <T> T parseFromString(String value);
+
+  public String getMd5String();
+
+  public String getJavaTypeName();
+
+  /**
+   * @return the serialized size of this {@link FieldType} in bytes
+   */
+  public int getSerializedSize();
+
+  public <T> void serialize(T value, ChannelBuffer buffer);
+
+  public <T> T deserialize(ChannelBuffer buffer);
+
+  public Field newVariableValue(String name);
+
+  public Field newVariableList(String name, int size);
+
+  public <T> Field newConstantValue(String name, T value);
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/field/FloatArrayField.java b/message_generator/src/main/java/org/ros/internal/message/field/FloatArrayField.java
new file mode 100644
index 0000000..fcbf50c
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/field/FloatArrayField.java
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.field;
+
+import com.google.common.base.Preconditions;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+
+import java.util.Arrays;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class FloatArrayField extends Field {
+
+  private final int size;
+
+  private float[] value;
+
+  public static FloatArrayField newVariable(String name, int size) {
+    return new FloatArrayField(PrimitiveFieldType.FLOAT32, name, size);
+  }
+
+  private FloatArrayField(FieldType type, String name, int size) {
+    super(type, name, false);
+    this.size = size;
+    setValue(new float[Math.max(0, size)]);
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public float[] getValue() {
+    return value;
+  }
+
+  @Override
+  public void setValue(Object value) {
+    Preconditions.checkArgument(size < 0 || ((float[]) value).length == size);
+    this.value = (float[]) value;
+  }
+
+  @Override
+  public void serialize(ChannelBuffer buffer) {
+    if (size < 0) {
+      buffer.writeInt(value.length);
+    }
+    for (float v : value) {
+      type.serialize(v, buffer);
+    }
+  }
+
+  @Override
+  public void deserialize(ChannelBuffer buffer) {
+    int currentSize = size;
+    if (currentSize < 0) {
+      currentSize = buffer.readInt();
+    }
+    value = new float[currentSize];
+    for (int i = 0; i < currentSize; i++) {
+      value[i] = buffer.readFloat();
+    }
+  }
+
+  @Override
+  public String getMd5String() {
+    return String.format("%s %s\n", type, name);
+  }
+
+  @Override
+  public String getJavaTypeName() {
+    return type.getJavaTypeName() + "[]";
+  }
+
+  @Override
+  public String toString() {
+    return "FloatArrayField<" + type + ", " + name + ">";
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = super.hashCode();
+    result = prime * result + ((value == null) ? 0 : value.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (!super.equals(obj))
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    FloatArrayField other = (FloatArrayField) obj;
+    if (value == null) {
+      if (other.value != null)
+        return false;
+    } else if (!Arrays.equals(value, other.value))
+      return false;
+    return true;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/field/IntegerArrayField.java b/message_generator/src/main/java/org/ros/internal/message/field/IntegerArrayField.java
new file mode 100644
index 0000000..adb0753
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/field/IntegerArrayField.java
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.field;
+
+import com.google.common.base.Preconditions;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+
+import java.util.Arrays;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class IntegerArrayField extends Field {
+
+  private final int size;
+
+  private int[] value;
+
+  public static IntegerArrayField newVariable(FieldType type, String name, int size) {
+    return new IntegerArrayField(type, name, size);
+  }
+
+  private IntegerArrayField(FieldType type, String name, int size) {
+    super(type, name, false);
+    this.size = size;
+    setValue(new int[Math.max(0, size)]);
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public int[] getValue() {
+    return value;
+  }
+
+  @Override
+  public void setValue(Object value) {
+    Preconditions.checkArgument(size < 0 || ((int[]) value).length == size);
+    this.value = (int[]) value;
+  }
+
+  @Override
+  public void serialize(ChannelBuffer buffer) {
+    if (size < 0) {
+      buffer.writeInt(value.length);
+    }
+    for (int v : value) {
+      type.serialize(v, buffer);
+    }
+  }
+
+  @Override
+  public void deserialize(ChannelBuffer buffer) {
+    int currentSize = size;
+    if (currentSize < 0) {
+      currentSize = buffer.readInt();
+    }
+    value = new int[currentSize];
+    for (int i = 0; i < currentSize; i++) {
+      value[i] = buffer.readInt();
+    }
+  }
+
+  @Override
+  public String getMd5String() {
+    return String.format("%s %s\n", type, name);
+  }
+
+  @Override
+  public String getJavaTypeName() {
+    return type.getJavaTypeName() + "[]";
+  }
+
+  @Override
+  public String toString() {
+    return "IntegerArrayField<" + type + ", " + name + ">";
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = super.hashCode();
+    result = prime * result + ((value == null) ? 0 : value.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (!super.equals(obj))
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    IntegerArrayField other = (IntegerArrayField) obj;
+    if (value == null) {
+      if (other.value != null)
+        return false;
+    } else if (!Arrays.equals(value, other.value))
+      return false;
+    return true;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/field/ListField.java b/message_generator/src/main/java/org/ros/internal/message/field/ListField.java
new file mode 100644
index 0000000..4f4caeb
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/field/ListField.java
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.field;
+
+import com.google.common.base.Preconditions;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ * 
+ * @param <T>
+ *          the value type
+ */
+public class ListField<T> extends Field {
+
+  private List<T> value;
+
+  public static <T> ListField<T> newVariable(FieldType type, String name) {
+    return new ListField<T>(type, name);
+  }
+
+  private ListField(FieldType type, String name) {
+    super(type, name, false);
+    value = new ArrayList<T>();
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public List<T> getValue() {
+    return value;
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public void setValue(Object value) {
+    Preconditions.checkNotNull(value);
+    this.value = (List<T>) value;
+  }
+
+  @Override
+  public void serialize(ChannelBuffer buffer) {
+    buffer.writeInt(value.size());
+    for (T v : value) {
+      type.serialize(v, buffer);
+    }
+  }
+
+  @Override
+  public void deserialize(ChannelBuffer buffer) {
+    value.clear();
+    int size = buffer.readInt();
+    for (int i = 0; i < size; i++) {
+      value.add(type.<T>deserialize(buffer));
+    }
+  }
+
+  @Override
+  public String getMd5String() {
+    return String.format("%s %s\n", type, name);
+  }
+
+  @Override
+  public String getJavaTypeName() {
+    return String.format("java.util.List<%s>", type.getJavaTypeName());
+  }
+
+  @Override
+  public String toString() {
+    return "ListField<" + type + ", " + name + ">";
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = super.hashCode();
+    result = prime * result + ((value == null) ? 0 : value.hashCode());
+    return result;
+  }
+
+  @SuppressWarnings("rawtypes")
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (!super.equals(obj))
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    ListField other = (ListField) obj;
+    if (value == null) {
+      if (other.value != null)
+        return false;
+    } else if (!value.equals(other.value))
+      return false;
+    return true;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/field/LongArrayField.java b/message_generator/src/main/java/org/ros/internal/message/field/LongArrayField.java
new file mode 100644
index 0000000..8c2a611
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/field/LongArrayField.java
@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.field;
+
+import com.google.common.base.Preconditions;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+
+import java.util.Arrays;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class LongArrayField extends Field {
+
+  private final int size;
+
+  private long[] value;
+
+  public static LongArrayField newVariable(FieldType type, String name, int size) {
+    Preconditions.checkArgument(type.equals(PrimitiveFieldType.UINT32)
+        || type.equals(PrimitiveFieldType.INT64) || type.equals(PrimitiveFieldType.UINT64));
+    return new LongArrayField(type, name, size);
+  }
+
+  private LongArrayField(FieldType type, String name, int size) {
+    super(type, name, false);
+    this.size = size;
+    setValue(new long[Math.max(0, size)]);
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public long[] getValue() {
+    return value;
+  }
+
+  @Override
+  public void setValue(Object value) {
+    Preconditions.checkArgument(size < 0 || ((long[]) value).length == size);
+    this.value = (long[]) value;
+  }
+
+  @Override
+  public void serialize(ChannelBuffer buffer) {
+    if (size < 0) {
+      buffer.writeInt(value.length);
+    }
+    for (long v : value) {
+      type.serialize(v, buffer);
+    }
+  }
+
+  @Override
+  public void deserialize(ChannelBuffer buffer) {
+    int currentSize = size;
+    if (currentSize < 0) {
+      currentSize = buffer.readInt();
+    }
+    value = new long[currentSize];
+    for (int i = 0; i < currentSize; i++) {
+      value[i] = buffer.readLong();
+    }
+  }
+
+  @Override
+  public String getMd5String() {
+    return String.format("%s %s\n", type, name);
+  }
+
+  @Override
+  public String getJavaTypeName() {
+    return type.getJavaTypeName() + "[]";
+  }
+
+  @Override
+  public String toString() {
+    return "LongArrayField<" + type + ", " + name + ">";
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = super.hashCode();
+    result = prime * result + ((value == null) ? 0 : value.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (!super.equals(obj))
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    LongArrayField other = (LongArrayField) obj;
+    if (value == null) {
+      if (other.value != null)
+        return false;
+    } else if (!Arrays.equals(value, other.value))
+      return false;
+    return true;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/field/MessageFieldType.java b/message_generator/src/main/java/org/ros/internal/message/field/MessageFieldType.java
new file mode 100644
index 0000000..b70e6fa
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/field/MessageFieldType.java
@@ -0,0 +1,136 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.field;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.ros.internal.message.DefaultMessageDeserializer;
+import org.ros.internal.message.DefaultMessageSerializer;
+import org.ros.internal.message.Message;
+import org.ros.message.MessageDeserializer;
+import org.ros.message.MessageFactory;
+import org.ros.message.MessageIdentifier;
+import org.ros.message.MessageSerializer;
+
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class MessageFieldType implements FieldType {
+
+  private final MessageIdentifier messageIdentifier;
+  private final MessageFactory messageFactory;
+  private final MessageSerializer<Message> serializer;
+  private final MessageDeserializer<Message> deserializer;
+
+  public MessageFieldType(MessageIdentifier messageIdentifier, MessageFactory messageFactory) {
+    this.messageIdentifier = messageIdentifier;
+    this.messageFactory = messageFactory;
+    serializer = new DefaultMessageSerializer();
+    deserializer = new DefaultMessageDeserializer<Message>(messageIdentifier, messageFactory);
+  }
+
+  public MessageFactory getMessageFactory() {
+    return messageFactory;
+  }
+
+  @Override
+  public Field newVariableValue(String name) {
+    return ValueField.newVariable(this, name);
+  }
+
+  @Override
+  public <T> Field newConstantValue(String name, T value) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public Field newVariableList(String name, int size) {
+    return ListField.newVariable(this, name);
+  }
+
+  @Override
+  public <T> T getDefaultValue() {
+    return getMessageFactory().newFromType(messageIdentifier.getType());
+  }
+
+  @Override
+  public String getMd5String() {
+    return null;
+  }
+
+  @Override
+  public String getJavaTypeName() {
+    return String.format("%s.%s", messageIdentifier.getPackage(), messageIdentifier.getName());
+  }
+
+  @Override
+  public int getSerializedSize() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String getName() {
+    return messageIdentifier.getType();
+  }
+
+  @Override
+  public <T> void serialize(T value, ChannelBuffer buffer) {
+    serializer.serialize((Message) value, buffer);
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public Message deserialize(ChannelBuffer buffer) {
+    return deserializer.deserialize(buffer);
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public Void parseFromString(String value) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String toString() {
+    return "MessageField<" + messageIdentifier + ">";
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = 1;
+    result = prime * result + ((messageIdentifier == null) ? 0 : messageIdentifier.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (obj == null)
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    MessageFieldType other = (MessageFieldType) obj;
+    if (messageIdentifier == null) {
+      if (other.messageIdentifier != null)
+        return false;
+    } else if (!messageIdentifier.equals(other.messageIdentifier))
+      return false;
+    return true;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/field/MessageFields.java b/message_generator/src/main/java/org/ros/internal/message/field/MessageFields.java
new file mode 100644
index 0000000..c79f3f3
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/field/MessageFields.java
@@ -0,0 +1,116 @@
+/*
+ * Copyright (C) 2012 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.field;
+
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
+
+import org.ros.exception.RosMessageRuntimeException;
+import org.ros.internal.message.context.MessageContext;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class MessageFields {
+
+  private final Map<String, Field> fields;
+  private final Map<String, Field> setters;
+  private final Map<String, Field> getters;
+  private final List<Field> orderedFields;
+
+  public MessageFields(MessageContext messageContext) {
+    fields = Maps.newHashMap();
+    setters = Maps.newHashMap();
+    getters = Maps.newHashMap();
+    orderedFields = Lists.newArrayList();
+    for (String name : messageContext.getFieldNames()) {
+      Field field = messageContext.getFieldFactory(name).create();
+      fields.put(name, field);
+      getters.put(messageContext.getFieldGetterName(name), field);
+      setters.put(messageContext.getFieldSetterName(name), field);
+      orderedFields.add(field);
+    }
+  }
+
+  public Field getField(String name) {
+    return fields.get(name);
+  }
+
+  public Field getSetterField(String name) {
+    return setters.get(name);
+  }
+
+  public Field getGetterField(String name) {
+    return getters.get(name);
+  }
+
+  public List<Field> getFields() {
+    return Collections.unmodifiableList(orderedFields);
+  }
+
+  public Object getFieldValue(String name) {
+    Field field = fields.get(name);
+    if (field != null) {
+      return field.getValue();
+    }
+    throw new RosMessageRuntimeException("Uknown field: " + name);
+  }
+
+  public void setFieldValue(String name, Object value) {
+    Field field = fields.get(name);
+    if (field != null) {
+      field.setValue(value);
+    } else {
+      throw new RosMessageRuntimeException("Uknown field: " + name);
+    }
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = 1;
+    result = prime * result + ((fields == null) ? 0 : fields.hashCode());
+    result = prime * result + ((orderedFields == null) ? 0 : orderedFields.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (obj == null)
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    MessageFields other = (MessageFields) obj;
+    if (fields == null) {
+      if (other.fields != null)
+        return false;
+    } else if (!fields.equals(other.fields))
+      return false;
+    if (orderedFields == null) {
+      if (other.orderedFields != null)
+        return false;
+    } else if (!orderedFields.equals(other.orderedFields))
+      return false;
+    return true;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/field/PrimitiveFieldType.java b/message_generator/src/main/java/org/ros/internal/message/field/PrimitiveFieldType.java
new file mode 100644
index 0000000..bed4916
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/field/PrimitiveFieldType.java
@@ -0,0 +1,714 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.field;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableSet;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.ros.message.Duration;
+import org.ros.message.Time;
+
+import java.nio.ByteBuffer;
+import java.nio.charset.Charset;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public enum PrimitiveFieldType implements FieldType {
+
+  BOOL {
+    @SuppressWarnings("unchecked")
+    @Override
+    public Boolean getDefaultValue() {
+      return Boolean.FALSE;
+    }
+
+    @Override
+    public BooleanArrayField newVariableList(String name, int size) {
+      return BooleanArrayField.newVariable(name, size);
+    }
+
+    @Override
+    public int getSerializedSize() {
+      return 1;
+    }
+
+    @Override
+    public <T> void serialize(T value, ChannelBuffer buffer) {
+      Preconditions.checkArgument(value instanceof Boolean);
+      buffer.writeByte((byte) ((Boolean) value ? 1 : 0));
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Boolean deserialize(ChannelBuffer buffer) {
+      return buffer.readByte() == 1;
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Boolean parseFromString(String value) {
+      return value.equals("1");
+    }
+
+    @Override
+    public String getJavaTypeName() {
+      return "boolean";
+    }
+  },
+  INT8 {
+    @SuppressWarnings("unchecked")
+    @Override
+    public Byte getDefaultValue() {
+      return Byte.valueOf((byte) 0);
+    }
+
+    @Override
+    public Field newVariableList(String name, int size) {
+      return ChannelBufferField.newVariable(this, name, size);
+    }
+
+    @Override
+    public int getSerializedSize() {
+      return 1;
+    }
+
+    @Override
+    public <T> void serialize(T value, ChannelBuffer buffer) {
+      Preconditions.checkArgument(value instanceof Byte);
+      buffer.writeByte((Byte) value);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Byte deserialize(ChannelBuffer buffer) {
+      return buffer.readByte();
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Byte parseFromString(String value) {
+      return Byte.parseByte(value);
+    }
+
+    @Override
+    public String getJavaTypeName() {
+      return "byte";
+    }
+  },
+  /**
+   * @deprecated replaced by {@link PrimitiveFieldType#INT8}
+   */
+  BYTE {
+    @SuppressWarnings("unchecked")
+    @Override
+    public Byte getDefaultValue() {
+      return INT8.getDefaultValue();
+    }
+
+    @Override
+    public Field newVariableList(String name, int size) {
+      return ChannelBufferField.newVariable(this, name, size);
+    }
+
+    @Override
+    public int getSerializedSize() {
+      return INT8.getSerializedSize();
+    }
+
+    @Override
+    public <T> void serialize(T value, ChannelBuffer buffer) {
+      INT8.serialize(value, buffer);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Byte deserialize(ChannelBuffer buffer) {
+      return INT8.deserialize(buffer);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Byte parseFromString(String value) {
+      return INT8.parseFromString(value);
+    }
+
+    @Override
+    public String getJavaTypeName() {
+      return INT8.getJavaTypeName();
+    }
+  },
+  UINT8 {
+    @SuppressWarnings("unchecked")
+    @Override
+    public Byte getDefaultValue() {
+      return INT8.getDefaultValue();
+    }
+
+    @Override
+    public Field newVariableList(String name, int size) {
+      return ChannelBufferField.newVariable(this, name, size);
+    }
+
+    @Override
+    public int getSerializedSize() {
+      return INT8.getSerializedSize();
+    }
+
+    @Override
+    public <T> void serialize(T value, ChannelBuffer buffer) {
+      INT8.serialize(value, buffer);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Byte deserialize(ChannelBuffer buffer) {
+      return INT8.deserialize(buffer);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Byte parseFromString(String value) {
+      return (byte) Short.parseShort(value);
+    }
+
+    @Override
+    public String getJavaTypeName() {
+      return INT8.getJavaTypeName();
+    }
+  },
+  /**
+   * @deprecated replaced by {@link PrimitiveFieldType#UINT8}
+   */
+  CHAR {
+    @SuppressWarnings("unchecked")
+    @Override
+    public Byte getDefaultValue() {
+      return UINT8.getDefaultValue();
+    }
+
+    @Override
+    public Field newVariableList(String name, int size) {
+      return ChannelBufferField.newVariable(this, name, size);
+    }
+
+    @Override
+    public int getSerializedSize() {
+      return UINT8.getSerializedSize();
+    }
+
+    @Override
+    public <T> void serialize(T value, ChannelBuffer buffer) {
+      UINT8.serialize(value, buffer);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Byte deserialize(ChannelBuffer buffer) {
+      return UINT8.deserialize(buffer);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Byte parseFromString(String value) {
+      return UINT8.parseFromString(value);
+    }
+
+    @Override
+    public String getJavaTypeName() {
+      return UINT8.getJavaTypeName();
+    }
+  },
+  INT16 {
+    @SuppressWarnings("unchecked")
+    @Override
+    public Short getDefaultValue() {
+      return Short.valueOf((short) 0);
+    }
+
+    @Override
+    public Field newVariableList(String name, int size) {
+      return ShortArrayField.newVariable(this, name, size);
+    }
+
+    @Override
+    public int getSerializedSize() {
+      return 2;
+    }
+
+    @Override
+    public <T> void serialize(T value, ChannelBuffer buffer) {
+      Preconditions.checkArgument(value instanceof Short);
+      buffer.writeShort((Short) value);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Short deserialize(ChannelBuffer buffer) {
+      return buffer.readShort();
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Short parseFromString(String value) {
+      return Short.parseShort(value);
+    }
+
+    @Override
+    public String getJavaTypeName() {
+      return "short";
+    }
+  },
+  UINT16 {
+    @SuppressWarnings("unchecked")
+    @Override
+    public Short getDefaultValue() {
+      return INT16.getDefaultValue();
+    }
+
+    @Override
+    public Field newVariableList(String name, int size) {
+      return ShortArrayField.newVariable(this, name, size);
+    }
+
+    @Override
+    public int getSerializedSize() {
+      return INT16.getSerializedSize();
+    }
+
+    @Override
+    public <T> void serialize(T value, ChannelBuffer buffer) {
+      INT16.serialize(value, buffer);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Short deserialize(ChannelBuffer buffer) {
+      return INT16.deserialize(buffer);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Short parseFromString(String value) {
+      return (short) Integer.parseInt(value);
+    }
+
+    @Override
+    public String getJavaTypeName() {
+      return INT16.getJavaTypeName();
+    }
+  },
+  INT32 {
+    @SuppressWarnings("unchecked")
+    @Override
+    public Integer getDefaultValue() {
+      return Integer.valueOf(0);
+    }
+
+    @Override
+    public Field newVariableList(String name, int size) {
+      return IntegerArrayField.newVariable(this, name, size);
+    }
+
+    @Override
+    public int getSerializedSize() {
+      return 4;
+    }
+
+    @Override
+    public <T> void serialize(T value, ChannelBuffer buffer) {
+      Preconditions.checkArgument(value instanceof Integer);
+      buffer.writeInt((Integer) value);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Integer deserialize(ChannelBuffer buffer) {
+      return buffer.readInt();
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Integer parseFromString(String value) {
+      return Integer.parseInt(value);
+    }
+
+    @Override
+    public String getJavaTypeName() {
+      return "int";
+    }
+  },
+  UINT32 {
+    @SuppressWarnings("unchecked")
+    @Override
+    public Integer getDefaultValue() {
+      return INT32.getDefaultValue();
+    }
+
+    @Override
+    public Field newVariableList(String name, int size) {
+      return IntegerArrayField.newVariable(this, name, size);
+    }
+
+    @Override
+    public int getSerializedSize() {
+      return INT32.getSerializedSize();
+    }
+
+    @Override
+    public <T> void serialize(T value, ChannelBuffer buffer) {
+      INT32.serialize(value, buffer);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Integer deserialize(ChannelBuffer buffer) {
+      return INT32.deserialize(buffer);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Integer parseFromString(String value) {
+      return (int) Long.parseLong(value);
+    }
+
+    @Override
+    public String getJavaTypeName() {
+      return INT32.getJavaTypeName();
+    }
+  },
+  INT64 {
+    @SuppressWarnings("unchecked")
+    @Override
+    public Long getDefaultValue() {
+      return Long.valueOf(0);
+    }
+
+    @Override
+    public Field newVariableList(String name, int size) {
+      return LongArrayField.newVariable(this, name, size);
+    }
+
+    @Override
+    public int getSerializedSize() {
+      return 8;
+    }
+
+    @Override
+    public <T> void serialize(T value, ChannelBuffer buffer) {
+      Preconditions.checkArgument(value instanceof Long);
+      buffer.writeLong((Long) value);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Long deserialize(ChannelBuffer buffer) {
+      return buffer.readLong();
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Long parseFromString(String value) {
+      return Long.parseLong(value);
+    }
+
+    @Override
+    public String getJavaTypeName() {
+      return "long";
+    }
+  },
+  UINT64 {
+    @SuppressWarnings("unchecked")
+    @Override
+    public Long getDefaultValue() {
+      return INT64.getDefaultValue();
+    }
+
+    @Override
+    public Field newVariableList(String name, int size) {
+      return INT64.newVariableList(name, size);
+    }
+
+    @Override
+    public int getSerializedSize() {
+      return INT64.getSerializedSize();
+    }
+
+    @Override
+    public <T> void serialize(T value, ChannelBuffer buffer) {
+      INT64.serialize(value, buffer);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Long deserialize(ChannelBuffer buffer) {
+      return INT64.deserialize(buffer);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Long parseFromString(String value) {
+      return INT64.parseFromString(value);
+    }
+
+    @Override
+    public String getJavaTypeName() {
+      return INT64.getJavaTypeName();
+    }
+  },
+  FLOAT32 {
+    @SuppressWarnings("unchecked")
+    @Override
+    public Float getDefaultValue() {
+      return Float.valueOf(0);
+    }
+
+    @Override
+    public Field newVariableList(String name, int size) {
+      return FloatArrayField.newVariable(name, size);
+    }
+
+    @Override
+    public int getSerializedSize() {
+      return 4;
+    }
+
+    @Override
+    public <T> void serialize(T value, ChannelBuffer buffer) {
+      Preconditions.checkArgument(value instanceof Float);
+      buffer.writeFloat((Float) value);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Float deserialize(ChannelBuffer buffer) {
+      return buffer.readFloat();
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Float parseFromString(String value) {
+      return Float.parseFloat(value);
+    }
+
+    @Override
+    public String getJavaTypeName() {
+      return "float";
+    }
+  },
+  FLOAT64 {
+    @SuppressWarnings("unchecked")
+    @Override
+    public Double getDefaultValue() {
+      return Double.valueOf(0);
+    }
+
+    @Override
+    public int getSerializedSize() {
+      return 8;
+    }
+
+    @Override
+    public Field newVariableList(String name, int size) {
+      return DoubleArrayField.newVariable(name, size);
+    }
+
+    @Override
+    public <T> void serialize(T value, ChannelBuffer buffer) {
+      Preconditions.checkArgument(value instanceof Double);
+      buffer.writeDouble((Double) value);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Double deserialize(ChannelBuffer buffer) {
+      return buffer.readDouble();
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Double parseFromString(String value) {
+      return Double.parseDouble(value);
+    }
+
+    @Override
+    public String getJavaTypeName() {
+      return "double";
+    }
+  },
+  STRING {
+    @SuppressWarnings("unchecked")
+    @Override
+    public String getDefaultValue() {
+      return "";
+    }
+
+    @Override
+    public Field newVariableList(String name, int size) {
+      return ListField.newVariable(this, name);
+    }
+
+    @Override
+    public int getSerializedSize() {
+      throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public <T> void serialize(T value, ChannelBuffer buffer) {
+      Preconditions.checkArgument(value instanceof String);
+      byte[] bytes = ((String) value).getBytes();
+      buffer.writeInt(bytes.length);
+      buffer.writeBytes(bytes);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public String deserialize(ChannelBuffer buffer) {
+      int length = buffer.readInt();
+      ByteBuffer stringBuffer = buffer.readSlice(length).toByteBuffer();
+      return Charset.forName("US-ASCII").decode(stringBuffer).toString();
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public String parseFromString(String value) {
+      return value;
+    }
+
+    @Override
+    public String getJavaTypeName() {
+      return "java.lang.String";
+    }
+  },
+  TIME {
+    @SuppressWarnings("unchecked")
+    @Override
+    public Time getDefaultValue() {
+      return new Time();
+    }
+
+    @Override
+    public Field newVariableList(String name, int size) {
+      return ListField.newVariable(this, name);
+    }
+
+    @Override
+    public int getSerializedSize() {
+      return 8;
+    }
+
+    @Override
+    public <T> void serialize(T value, ChannelBuffer buffer) {
+      Preconditions.checkArgument(value instanceof Time);
+      buffer.writeInt(((Time) value).secs);
+      buffer.writeInt(((Time) value).nsecs);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Time deserialize(ChannelBuffer buffer) {
+      return new Time(buffer.readInt(), buffer.readInt());
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Void parseFromString(String value) {
+      throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public String getJavaTypeName() {
+      return Time.class.getName();
+    }
+  },
+  DURATION {
+    @SuppressWarnings("unchecked")
+    @Override
+    public Duration getDefaultValue() {
+      return new Duration();
+    }
+
+    @Override
+    public Field newVariableList(String name, int size) {
+      return ListField.newVariable(this, name);
+    }
+
+    @Override
+    public int getSerializedSize() {
+      return 8;
+    }
+
+    @Override
+    public <T> void serialize(T value, ChannelBuffer buffer) {
+      Preconditions.checkArgument(value instanceof Duration);
+      buffer.writeInt(((Duration) value).secs);
+      buffer.writeInt(((Duration) value).nsecs);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Duration deserialize(ChannelBuffer buffer) {
+      return new Duration(buffer.readInt(), buffer.readInt());
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Void parseFromString(String value) {
+      throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public String getJavaTypeName() {
+      return Duration.class.getName();
+    }
+  };
+
+  private static final ImmutableSet<String> TYPE_NAMES;
+
+  static {
+    ImmutableSet.Builder<String> builder = ImmutableSet.<String>builder();
+    for (PrimitiveFieldType type : values()) {
+      builder.add(type.getName());
+    }
+    TYPE_NAMES = builder.build();
+  }
+
+  public static boolean existsFor(String name) {
+    return TYPE_NAMES.contains(name);
+  }
+
+  @Override
+  public Field newVariableValue(String name) {
+    return ValueField.newVariable(this, name);
+  }
+
+  @Override
+  public <T> Field newConstantValue(String name, T value) {
+    return ValueField.newConstant(this, name, value);
+  }
+
+  @Override
+  public String getName() {
+    return toString().toLowerCase();
+  }
+
+  @Override
+  public String getMd5String() {
+    return getName();
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/field/ShortArrayField.java b/message_generator/src/main/java/org/ros/internal/message/field/ShortArrayField.java
new file mode 100644
index 0000000..e77b72a
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/field/ShortArrayField.java
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.field;
+
+import com.google.common.base.Preconditions;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+
+import java.util.Arrays;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class ShortArrayField extends Field {
+
+  private final int size;
+
+  private short[] value;
+
+  public static ShortArrayField newVariable(FieldType type, String name, int size) {
+    return new ShortArrayField(type, name, size);
+  }
+
+  private ShortArrayField(FieldType type, String name, int size) {
+    super(type, name, false);
+    this.size = size;
+    setValue(new short[Math.max(0, size)]);
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public short[] getValue() {
+    return value;
+  }
+
+  @Override
+  public void setValue(Object value) {
+    Preconditions.checkArgument(size < 0 || ((short[]) value).length == size);
+    this.value = (short[]) value;
+  }
+
+  @Override
+  public void serialize(ChannelBuffer buffer) {
+    if (size < 0) {
+      buffer.writeInt(value.length);
+    }
+    for (short v : value) {
+      type.serialize(v, buffer);
+    }
+  }
+
+  @Override
+  public void deserialize(ChannelBuffer buffer) {
+    int currentSize = size;
+    if (currentSize < 0) {
+      currentSize = buffer.readInt();
+    }
+    value = new short[currentSize];
+    for (int i = 0; i < currentSize; i++) {
+      value[i] = buffer.readShort();
+    }
+  }
+
+  @Override
+  public String getMd5String() {
+    return String.format("%s %s\n", type, name);
+  }
+
+  @Override
+  public String getJavaTypeName() {
+    return type.getJavaTypeName() + "[]";
+  }
+
+  @Override
+  public String toString() {
+    return "ShortArrayField<" + type + ", " + name + ">";
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = super.hashCode();
+    result = prime * result + ((value == null) ? 0 : value.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (!super.equals(obj))
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    ShortArrayField other = (ShortArrayField) obj;
+    if (value == null) {
+      if (other.value != null)
+        return false;
+    } else if (!Arrays.equals(value, other.value))
+      return false;
+    return true;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/field/ValueField.java b/message_generator/src/main/java/org/ros/internal/message/field/ValueField.java
new file mode 100644
index 0000000..d2baacf
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/field/ValueField.java
@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.field;
+
+import com.google.common.base.Preconditions;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+class ValueField<T> extends Field {
+
+  private T value;
+
+  static <T> ValueField<T> newConstant(FieldType type, String name, T value) {
+    return new ValueField<T>(type, name, value, true);
+  }
+
+  static <T> ValueField<T> newVariable(FieldType type, String name) {
+    return new ValueField<T>(type, name, null, false);
+  }
+
+  private ValueField(FieldType type, String name, T value, boolean isConstant) {
+    super(type, name, isConstant);
+    this.value = value;
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public T getValue() {
+    if (value == null) {
+      setValue(type.getDefaultValue());
+    }
+    return value;
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public void setValue(Object value) {
+    Preconditions.checkNotNull(value);
+    Preconditions.checkState(!isConstant);
+    this.value = (T) value;
+  }
+
+  @Override
+  public void serialize(ChannelBuffer buffer) {
+    type.serialize(getValue(), buffer);
+  }
+
+  @Override
+  public void deserialize(ChannelBuffer buffer) {
+    Preconditions.checkState(!isConstant);
+    setValue(type.<T>deserialize(buffer));
+  }
+
+  @Override
+  public String getMd5String() {
+    return String.format("%s %s\n", type, name);
+  }
+
+  @Override
+  public String getJavaTypeName() {
+    return type.getJavaTypeName();
+  }
+
+  @Override
+  public String toString() {
+    return "ValueField<" + type + ", " + name + ">";
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = super.hashCode();
+    result = prime * result + ((getValue() == null) ? 0 : getValue().hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (!super.equals(obj))
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    Field other = (Field) obj;
+    if (getValue() == null) {
+      if (other.getValue() != null)
+        return false;
+    } else if (!getValue().equals(other.getValue()))
+      return false;
+    return true;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/package-info.java b/message_generator/src/main/java/org/ros/internal/message/package-info.java
new file mode 100644
index 0000000..a59b1c8
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/package-info.java
@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2012 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+/**
+ * Provides internal classes for representing messages.
+ * <p>
+ * These classes should _not_ be used directly outside of the org.ros package.
+ */
+package org.ros.internal.message;
\ No newline at end of file
diff --git a/message_generator/src/main/java/org/ros/internal/message/service/ServiceDefinitionFileProvider.java b/message_generator/src/main/java/org/ros/internal/message/service/ServiceDefinitionFileProvider.java
new file mode 100644
index 0000000..31b258f
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/service/ServiceDefinitionFileProvider.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.service;
+
+import org.ros.internal.message.definition.MessageDefinitionFileProvider;
+
+import org.apache.commons.io.filefilter.FileFilterUtils;
+import org.apache.commons.io.filefilter.IOFileFilter;
+import org.ros.internal.message.StringFileProvider;
+
+import java.io.File;
+import java.io.FileFilter;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class ServiceDefinitionFileProvider extends MessageDefinitionFileProvider {
+
+  private static final String PARENT = "srv";
+  private static final String SUFFIX = "srv";
+
+  private static StringFileProvider newStringFileProvider() {
+    IOFileFilter extensionFilter = FileFilterUtils.suffixFileFilter(SUFFIX);
+    IOFileFilter parentBaseNameFilter = FileFilterUtils.asFileFilter(new FileFilter() {
+      @Override
+      public boolean accept(File file) {
+        return getParentBaseName(file.getAbsolutePath()).equals(PARENT);
+      }
+    });
+    IOFileFilter fileFilter = FileFilterUtils.andFileFilter(extensionFilter, parentBaseNameFilter);
+    return new StringFileProvider(fileFilter);
+  }
+
+  public ServiceDefinitionFileProvider() {
+    super(newStringFileProvider());
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/service/ServiceDefinitionResourceProvider.java b/message_generator/src/main/java/org/ros/internal/message/service/ServiceDefinitionResourceProvider.java
new file mode 100644
index 0000000..af35e3f
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/service/ServiceDefinitionResourceProvider.java
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.service;
+
+import com.google.common.base.Preconditions;
+
+import org.ros.internal.message.StringResourceProvider;
+import org.ros.message.MessageDefinitionProvider;
+import org.ros.message.MessageIdentifier;
+
+import java.util.Collection;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class ServiceDefinitionResourceProvider implements MessageDefinitionProvider {
+
+  private final StringResourceProvider stringResourceProvider;
+
+  public ServiceDefinitionResourceProvider() {
+    stringResourceProvider = new StringResourceProvider();
+  }
+
+  private String serviceTypeToResourceName(String serviceType) {
+    Preconditions.checkArgument(serviceType.contains("/"), "Service type must be fully qualified: "
+        + serviceType);
+    String[] packageAndType = serviceType.split("/", 2);
+    return String.format("/%s/srv/%s.srv", packageAndType[0], packageAndType[1]);
+  }
+
+  @Override
+  public String get(String serviceType) {
+    return stringResourceProvider.get(serviceTypeToResourceName(serviceType));
+  }
+
+  @Override
+  public boolean has(String serviceType) {
+    return stringResourceProvider.has(serviceTypeToResourceName(serviceType));
+  }
+
+  public void add(String serviceType, String serviceDefinition) {
+    stringResourceProvider.addStringToCache(serviceTypeToResourceName(serviceType),
+        serviceDefinition);
+  }
+
+  @Override
+  public Collection<String> getPackages() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public Collection<MessageIdentifier> getMessageIdentifiersByPackage(String pkg) {
+    throw new UnsupportedOperationException();
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/service/ServiceDescription.java b/message_generator/src/main/java/org/ros/internal/message/service/ServiceDescription.java
new file mode 100644
index 0000000..95251a0
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/service/ServiceDescription.java
@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.service;
+
+import org.ros.internal.message.definition.MessageDefinitionTupleParser;
+
+import org.ros.message.MessageDeclaration;
+import org.ros.message.MessageIdentifier;
+
+import java.util.List;
+
+/**
+ * The description of a ROS service.
+ * 
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class ServiceDescription extends MessageDeclaration {
+
+  private final String requestType;
+  private final String requestDefinition;
+  private final String responseType;
+  private final String responseDefinition;
+  private final String md5Checksum;
+
+  public ServiceDescription(String type, String definition, String md5Checksum) {
+    super(MessageIdentifier.of(type), definition);
+    this.md5Checksum = md5Checksum;
+    List<String> requestAndResponse = MessageDefinitionTupleParser.parse(definition, 2);
+    requestType = type + "Request";
+    responseType = type + "Response";
+    requestDefinition = requestAndResponse.get(0);
+    responseDefinition = requestAndResponse.get(1);
+  }
+
+  public String getMd5Checksum() {
+    return md5Checksum;
+  }
+
+  public String getRequestType() {
+    return requestType;
+  }
+
+  public String getRequestDefinition() {
+    return requestDefinition;
+  }
+
+  public String getResponseType() {
+    return responseType;
+  }
+
+  public String getResponseDefinition() {
+    return responseDefinition;
+  }
+
+  @Override
+  public String toString() {
+    return "ServiceDescription<" + getType() + ", " + md5Checksum + ">";
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = super.hashCode();
+    result = prime * result + ((md5Checksum == null) ? 0 : md5Checksum.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (!super.equals(obj))
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    ServiceDescription other = (ServiceDescription) obj;
+    if (md5Checksum == null) {
+      if (other.md5Checksum != null)
+        return false;
+    } else if (!md5Checksum.equals(other.md5Checksum))
+      return false;
+    return true;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/service/ServiceDescriptionFactory.java b/message_generator/src/main/java/org/ros/internal/message/service/ServiceDescriptionFactory.java
new file mode 100644
index 0000000..269d402
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/service/ServiceDescriptionFactory.java
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.service;
+
+import org.ros.internal.message.Md5Generator;
+import org.ros.message.MessageDefinitionProvider;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class ServiceDescriptionFactory {
+
+  private final MessageDefinitionProvider messageDefinitionProvider;
+  private final Md5Generator md5Generator;
+
+  public ServiceDescriptionFactory(MessageDefinitionProvider messageDefinitionProvider) {
+    this.messageDefinitionProvider = messageDefinitionProvider;
+    md5Generator = new Md5Generator(messageDefinitionProvider);
+  }
+
+  public ServiceDescription newFromType(String serviceType) {
+    String serviceDefinition = messageDefinitionProvider.get(serviceType);
+    String md5Checksum = md5Generator.generate(serviceType);
+    return new ServiceDescription(serviceType, serviceDefinition, md5Checksum);
+  }
+
+  public boolean hasType(String serviceType) {
+    return messageDefinitionProvider.has(serviceType);
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/service/ServiceRequestMessageFactory.java b/message_generator/src/main/java/org/ros/internal/message/service/ServiceRequestMessageFactory.java
new file mode 100644
index 0000000..862b20d
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/service/ServiceRequestMessageFactory.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.service;
+
+import org.ros.internal.message.DefaultMessageFactory;
+import org.ros.internal.message.DefaultMessageInterfaceClassProvider;
+import org.ros.internal.message.MessageProxyFactory;
+import org.ros.message.MessageDeclaration;
+import org.ros.message.MessageDefinitionProvider;
+import org.ros.message.MessageFactory;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class ServiceRequestMessageFactory implements MessageFactory {
+
+  private final ServiceDescriptionFactory serviceDescriptionFactory;
+  private final MessageFactory messageFactory;
+  private final MessageProxyFactory messageProxyFactory;
+
+  public ServiceRequestMessageFactory(MessageDefinitionProvider messageDefinitionProvider) {
+    serviceDescriptionFactory = new ServiceDescriptionFactory(messageDefinitionProvider);
+    messageFactory = new DefaultMessageFactory(messageDefinitionProvider);
+    messageProxyFactory =
+        new MessageProxyFactory(new DefaultMessageInterfaceClassProvider(), messageFactory);
+  }
+
+  @Override
+  public <T> T newFromType(String serviceType) {
+    ServiceDescription serviceDescription = serviceDescriptionFactory.newFromType(serviceType);
+    MessageDeclaration messageDeclaration =
+        MessageDeclaration.of(serviceDescription.getRequestType(),
+            serviceDescription.getRequestDefinition());
+    return messageProxyFactory.newMessageProxy(messageDeclaration);
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/service/ServiceRequestMessageInterfaceClassProvider.java b/message_generator/src/main/java/org/ros/internal/message/service/ServiceRequestMessageInterfaceClassProvider.java
new file mode 100644
index 0000000..24b4b52
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/service/ServiceRequestMessageInterfaceClassProvider.java
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.service;
+
+import org.ros.internal.message.MessageInterfaceClassProvider;
+import org.ros.internal.message.RawMessage;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class ServiceRequestMessageInterfaceClassProvider implements MessageInterfaceClassProvider {
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public <T> Class<T> get(String messageType) {
+    try {
+      String className = messageType.replace("/", ".") + "$Request";
+      return (Class<T>) getClass().getClassLoader().loadClass(className);
+    } catch (ClassNotFoundException e) {
+      return (Class<T>) RawMessage.class;
+    }
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/service/ServiceResponseMessageFactory.java b/message_generator/src/main/java/org/ros/internal/message/service/ServiceResponseMessageFactory.java
new file mode 100644
index 0000000..c325c44
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/service/ServiceResponseMessageFactory.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.service;
+
+import org.ros.internal.message.DefaultMessageFactory;
+import org.ros.internal.message.DefaultMessageInterfaceClassProvider;
+import org.ros.internal.message.MessageProxyFactory;
+import org.ros.message.MessageDeclaration;
+import org.ros.message.MessageDefinitionProvider;
+import org.ros.message.MessageFactory;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class ServiceResponseMessageFactory implements MessageFactory {
+
+  private final ServiceDescriptionFactory serviceDescriptionFactory;
+  private final MessageFactory messageFactory;
+  private final MessageProxyFactory messageProxyFactory;
+
+  public ServiceResponseMessageFactory(MessageDefinitionProvider messageDefinitionProvider) {
+    serviceDescriptionFactory = new ServiceDescriptionFactory(messageDefinitionProvider);
+    messageFactory = new DefaultMessageFactory(messageDefinitionProvider);
+    messageProxyFactory =
+        new MessageProxyFactory(new DefaultMessageInterfaceClassProvider(), messageFactory);
+  }
+
+  @Override
+  public <T> T newFromType(String serviceType) {
+    ServiceDescription serviceDescription = serviceDescriptionFactory.newFromType(serviceType);
+    MessageDeclaration messageDeclaration =
+        MessageDeclaration.of(serviceDescription.getResponseType(),
+            serviceDescription.getResponseDefinition());
+    return messageProxyFactory.newMessageProxy(messageDeclaration);
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/service/ServiceResponseMessageInterfaceClassProvider.java b/message_generator/src/main/java/org/ros/internal/message/service/ServiceResponseMessageInterfaceClassProvider.java
new file mode 100644
index 0000000..0e61fb9
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/service/ServiceResponseMessageInterfaceClassProvider.java
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.service;
+
+import org.ros.internal.message.MessageInterfaceClassProvider;
+import org.ros.internal.message.RawMessage;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class ServiceResponseMessageInterfaceClassProvider implements MessageInterfaceClassProvider {
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public <T> Class<T> get(String messageType) {
+    try {
+      String className = messageType.replace("/", ".") + "$Response";
+      return (Class<T>) getClass().getClassLoader().loadClass(className);
+    } catch (ClassNotFoundException e) {
+      return (Class<T>) RawMessage.class;
+    }
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/service/package-info.java b/message_generator/src/main/java/org/ros/internal/message/service/package-info.java
new file mode 100644
index 0000000..82c8038
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/service/package-info.java
@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2012 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+/**
+ * Provides internal classes for representing service messages.
+ * <p>
+ * These classes should _not_ be used directly outside of the org.ros package.
+ */
+package org.ros.internal.message.service;
\ No newline at end of file
diff --git a/message_generator/src/main/java/org/ros/internal/message/topic/TopicDefinitionFileProvider.java b/message_generator/src/main/java/org/ros/internal/message/topic/TopicDefinitionFileProvider.java
new file mode 100644
index 0000000..5cc8e1e
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/topic/TopicDefinitionFileProvider.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.topic;
+
+import org.ros.internal.message.definition.MessageDefinitionFileProvider;
+
+import org.apache.commons.io.filefilter.FileFilterUtils;
+import org.apache.commons.io.filefilter.IOFileFilter;
+import org.ros.internal.message.StringFileProvider;
+
+import java.io.File;
+import java.io.FileFilter;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class TopicDefinitionFileProvider extends MessageDefinitionFileProvider {
+
+  private static final String PARENT = "msg";
+  private static final String SUFFIX = "msg";
+
+  private static StringFileProvider newStringFileProvider() {
+    IOFileFilter extensionFilter = FileFilterUtils.suffixFileFilter(SUFFIX);
+    IOFileFilter parentBaseNameFilter = FileFilterUtils.asFileFilter(new FileFilter() {
+      @Override
+      public boolean accept(File file) {
+        return getParentBaseName(file.getAbsolutePath()).equals(PARENT);
+      }
+    });
+    IOFileFilter fileFilter = FileFilterUtils.andFileFilter(extensionFilter, parentBaseNameFilter);
+    return new StringFileProvider(fileFilter);
+  }
+
+  public TopicDefinitionFileProvider() {
+    super(newStringFileProvider());
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/topic/TopicDefinitionResourceProvider.java b/message_generator/src/main/java/org/ros/internal/message/topic/TopicDefinitionResourceProvider.java
new file mode 100644
index 0000000..08dce89
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/topic/TopicDefinitionResourceProvider.java
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.topic;
+
+import com.google.common.annotations.VisibleForTesting;
+
+import org.ros.internal.message.StringResourceProvider;
+import org.ros.message.MessageDefinitionProvider;
+import org.ros.message.MessageIdentifier;
+
+import java.util.Collection;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class TopicDefinitionResourceProvider implements MessageDefinitionProvider {
+
+  private final StringResourceProvider stringResourceProvider;
+
+  public TopicDefinitionResourceProvider() {
+    stringResourceProvider = new StringResourceProvider();
+  }
+
+  private String topicTypeToResourceName(String topicType) {
+    MessageIdentifier messageIdentifier = MessageIdentifier.of(topicType);
+    return String.format("/%s/msg/%s.msg", messageIdentifier.getPackage(),
+        messageIdentifier.getName());
+  }
+
+  @Override
+  public String get(String topicType) {
+    return stringResourceProvider.get(topicTypeToResourceName(topicType));
+  }
+
+  @Override
+  public boolean has(String topicType) {
+    return stringResourceProvider.has(topicTypeToResourceName(topicType));
+  }
+
+  @VisibleForTesting
+  public void add(String topicType, String topicDefinition) {
+    stringResourceProvider.addStringToCache(topicTypeToResourceName(topicType), topicDefinition);
+  }
+
+  @Override
+  public Collection<String> getPackages() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public Collection<MessageIdentifier> getMessageIdentifiersByPackage(String pkg) {
+    throw new UnsupportedOperationException();
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/topic/TopicDescription.java b/message_generator/src/main/java/org/ros/internal/message/topic/TopicDescription.java
new file mode 100644
index 0000000..50c9ad3
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/topic/TopicDescription.java
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.topic;
+
+import org.ros.message.MessageDeclaration;
+import org.ros.message.MessageIdentifier;
+
+/**
+ * The description of a ROS topic.
+ * 
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class TopicDescription extends MessageDeclaration {
+
+  private final String md5Checksum;
+
+  public TopicDescription(String type, String definition, String md5Checksum) {
+    super(MessageIdentifier.of(type), definition);
+    this.md5Checksum = md5Checksum;
+  }
+
+  public String getMd5Checksum() {
+    return md5Checksum;
+  }
+
+  @Override
+  public String toString() {
+    return "TopicDescription<" + getType() + ", " + md5Checksum + ">";
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = super.hashCode();
+    result = prime * result + ((md5Checksum == null) ? 0 : md5Checksum.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (!super.equals(obj))
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    TopicDescription other = (TopicDescription) obj;
+    if (md5Checksum == null) {
+      if (other.md5Checksum != null)
+        return false;
+    } else if (!md5Checksum.equals(other.md5Checksum))
+      return false;
+    return true;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/topic/TopicDescriptionFactory.java b/message_generator/src/main/java/org/ros/internal/message/topic/TopicDescriptionFactory.java
new file mode 100644
index 0000000..27e8620
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/topic/TopicDescriptionFactory.java
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.topic;
+
+import org.ros.internal.message.Md5Generator;
+import org.ros.message.MessageDefinitionProvider;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class TopicDescriptionFactory {
+
+  private final MessageDefinitionProvider messageDefinitionProvider;
+  private final Md5Generator md5Generator;
+
+  public TopicDescriptionFactory(MessageDefinitionProvider messageDefinitionProvider) {
+    this.messageDefinitionProvider = messageDefinitionProvider;
+    md5Generator = new Md5Generator(messageDefinitionProvider);
+  }
+
+  public TopicDescription newFromType(String topicType) {
+    String md5Checksum = md5Generator.generate(topicType);
+    String topicDefinition = messageDefinitionProvider.get(topicType);
+    return new TopicDescription(topicType, topicDefinition, md5Checksum);
+  }
+
+  public boolean hasType(String topicType) {
+    return messageDefinitionProvider.has(topicType);
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/topic/TopicMessageFactory.java b/message_generator/src/main/java/org/ros/internal/message/topic/TopicMessageFactory.java
new file mode 100644
index 0000000..b329386
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/topic/TopicMessageFactory.java
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2012 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.internal.message.topic;
+
+import org.ros.internal.message.DefaultMessageFactory;
+import org.ros.message.MessageDefinitionProvider;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class TopicMessageFactory extends DefaultMessageFactory {
+
+  public TopicMessageFactory(MessageDefinitionProvider messageDefinitionProvider) {
+    super(messageDefinitionProvider);
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/internal/message/topic/package-info.java b/message_generator/src/main/java/org/ros/internal/message/topic/package-info.java
new file mode 100644
index 0000000..d270dee
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/internal/message/topic/package-info.java
@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2012 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+/**
+ * Provides internal classes for representing topic messages.
+ * <p>
+ * These classes should _not_ be used directly outside of the org.ros package.
+ */
+package org.ros.internal.message.topic;
\ No newline at end of file
diff --git a/message_generator/src/main/java/org/ros/message/Duration.java b/message_generator/src/main/java/org/ros/message/Duration.java
new file mode 100644
index 0000000..d67c8c8
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/message/Duration.java
@@ -0,0 +1,167 @@
+/*
+ * Software License Agreement (BSD License)
+ *
+ *  Copyright (c) 2008, Willow Garage, Inc.
+ *  All rights reserved.
+ *
+ *  Redistribution and use in source and binary forms, with or without
+ *  modification, are permitted provided that the following conditions
+ *  are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above
+ *     copyright notice, this list of conditions and the following
+ *     disclaimer in the documentation and/or other materials provided
+ *     with the distribution.
+ *   * Neither the name of Willow Garage, Inc. nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ *  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ *  COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ *  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ *  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ *  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ *  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ *  ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ *  POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.ros.message;
+
+/**
+ * ROS Duration representation. Time and Duration are primitive types in ROS.
+ * ROS represents each as two 32-bit integers: seconds and nanoseconds since
+ * epoch.
+ * 
+ * http://www.ros.org/wiki/msg
+ * 
+ * @author Jason Wolfe
+ * @author kwc@willowgarage.com (Ken Conley)
+ * 
+ */
+public class Duration implements Comparable<Duration> {
+
+  public static final Duration MAX_VALUE = new Duration(Integer.MAX_VALUE, 999999999);
+
+  public int secs;
+  public int nsecs;
+
+  public Duration() {
+  }
+
+  public Duration(int secs, int nsecs) {
+    this.secs = secs;
+    this.nsecs = nsecs;
+    normalize();
+  }
+
+  public Duration(double secs) {
+    this.secs = (int) secs;
+    this.nsecs = (int) ((secs - this.secs) * 1000000000);
+    normalize();
+  }
+
+  public Duration(Duration t) {
+    this.secs = t.secs;
+    this.nsecs = t.nsecs;
+  }
+
+  public Duration add(Duration d) {
+    return new Duration(secs + d.secs, nsecs + d.nsecs);
+  }
+
+  public Duration subtract(Duration d) {
+    return new Duration(secs - d.secs, nsecs - d.nsecs);
+  }
+
+  public static Duration fromMillis(long durationInMillis) {
+    int secs = (int) (durationInMillis / 1000);
+    int nsecs = (int) (durationInMillis % 1000) * 1000000;
+    return new Duration(secs, nsecs);
+  }
+
+  public static Duration fromNano(long durationInNs) {
+    int secs = (int) (durationInNs / 1000000000);
+    int nsecs = (int) (durationInNs % 1000000000);
+    return new Duration(secs, nsecs);
+  }
+
+  public void normalize() {
+    while (nsecs < 0) {
+      nsecs += 1000000000;
+      secs -= 1;
+    }
+    while (nsecs >= 1000000000) {
+      nsecs -= 1000000000;
+      secs += 1;
+    }
+  }
+
+  public long totalNsecs() {
+    return ((long) secs) * 1000000000 + nsecs;
+  }
+
+  public boolean isZero() {
+    return totalNsecs() == 0;
+  }
+
+  public boolean isPositive() {
+    return totalNsecs() > 0;
+  }
+
+  public boolean isNegative() {
+    return totalNsecs() < 0;
+  }
+
+  @Override
+  public String toString() {
+    return secs + ":" + nsecs;
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = 1;
+    result = prime * result + nsecs;
+    result = prime * result + secs;
+    return result;
+  }
+
+  @Override
+  /**
+   * Check for equality between Time objects.  
+   * equals() does not normalize Time representations, so fields must match exactly.
+   */
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (obj == null)
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    Duration other = (Duration) obj;
+    if (nsecs != other.nsecs)
+      return false;
+    if (secs != other.secs)
+      return false;
+    return true;
+  }
+
+  @Override
+  public int compareTo(Duration d) {
+    if ((secs > d.secs) || ((secs == d.secs) && nsecs > d.nsecs)) {
+      return 1;
+    }
+    if ((secs == d.secs) && (nsecs == d.nsecs)) {
+      return 0;
+    }
+    return -1;
+  }
+
+}
diff --git a/message_generator/src/main/java/org/ros/message/MessageDeclaration.java b/message_generator/src/main/java/org/ros/message/MessageDeclaration.java
new file mode 100644
index 0000000..57a846e
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/message/MessageDeclaration.java
@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.message;
+
+import com.google.common.base.Preconditions;
+
+/**
+ * An {@link MessageIdentifier} and definition pair from which all qualities of
+ * the message uniquely identifiable by the {@link MessageIdentifier} can be
+ * derived.
+ * 
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class MessageDeclaration {
+
+  private final MessageIdentifier messageIdentifier;
+  private final String definition;
+
+  public static MessageDeclaration of(String type, String definition) {
+    Preconditions.checkNotNull(type);
+    Preconditions.checkNotNull(definition);
+    return new MessageDeclaration(MessageIdentifier.of(type), definition);
+  }
+
+  /**
+   * @param messageIdentifier
+   *          the {@link MessageIdentifier}
+   * @param definition
+   *          the message definition
+   */
+  public MessageDeclaration(MessageIdentifier messageIdentifier, String definition) {
+    Preconditions.checkNotNull(messageIdentifier);
+    Preconditions.checkNotNull(definition);
+    this.messageIdentifier = messageIdentifier;
+    this.definition = definition;
+  }
+
+  public MessageIdentifier getMessageIdentifier() {
+    return messageIdentifier;
+  }
+
+  public String getType() {
+    return messageIdentifier.getType();
+  }
+
+  public String getPackage() {
+    return messageIdentifier.getPackage();
+  }
+
+  public String getName() {
+    return messageIdentifier.getName();
+  }
+
+  public String getDefinition() {
+    Preconditions.checkNotNull(definition);
+    return definition;
+  }
+
+  @Override
+  public String toString() {
+    return String.format("MessageDeclaration<%s>", messageIdentifier.toString());
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = 1;
+    result = prime * result + ((definition == null) ? 0 : definition.hashCode());
+    result = prime * result + ((messageIdentifier == null) ? 0 : messageIdentifier.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (obj == null)
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    MessageDeclaration other = (MessageDeclaration) obj;
+    if (definition == null) {
+      if (other.definition != null)
+        return false;
+    } else if (!definition.equals(other.definition))
+      return false;
+    if (messageIdentifier == null) {
+      if (other.messageIdentifier != null)
+        return false;
+    } else if (!messageIdentifier.equals(other.messageIdentifier))
+      return false;
+    return true;
+  }
+}
\ No newline at end of file
diff --git a/message_generator/src/main/java/org/ros/message/MessageDefinitionProvider.java b/message_generator/src/main/java/org/ros/message/MessageDefinitionProvider.java
new file mode 100644
index 0000000..b62715c
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/message/MessageDefinitionProvider.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.message;
+
+import java.util.Collection;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public interface MessageDefinitionProvider {
+
+  /**
+   * @param messageType
+   *          the type of message definition to provide
+   * @return the message definition for the specified type
+   */
+  String get(String messageType);
+
+  /**
+   * @param messageType
+   *          the type of message definition to provide
+   * @return {@code true} if the definition for the specified type is available,
+   *         {@code false} otherwise
+   */
+  boolean has(String messageType);
+
+  Collection<String> getPackages();
+
+  /**
+   * @param pkg
+   *          the name of the package to filter on
+   * @return the {@link MessageIdentifier}s for all messages defined in the
+   *         specified package
+   */
+  Collection<MessageIdentifier> getMessageIdentifiersByPackage(String pkg);
+}
diff --git a/message_generator/src/main/java/org/ros/message/MessageDeserializer.java b/message_generator/src/main/java/org/ros/message/MessageDeserializer.java
new file mode 100644
index 0000000..326c510
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/message/MessageDeserializer.java
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.message;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ * 
+ * @param <T>
+ *          the type of message that this {@link MessageDeserializer} can
+ *          deserialize
+ */
+public interface MessageDeserializer<T> {
+  
+  T deserialize(ChannelBuffer buffer);
+}
diff --git a/message_generator/src/main/java/org/ros/message/MessageFactory.java b/message_generator/src/main/java/org/ros/message/MessageFactory.java
new file mode 100644
index 0000000..9babe2f
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/message/MessageFactory.java
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.message;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public interface MessageFactory {
+
+  /**
+   * @param messageType
+   *          the type of message to create
+   * @return a new message
+   */
+  <T> T newFromType(String messageType);
+}
diff --git a/message_generator/src/main/java/org/ros/message/MessageFactoryProvider.java b/message_generator/src/main/java/org/ros/message/MessageFactoryProvider.java
new file mode 100644
index 0000000..24e8713
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/message/MessageFactoryProvider.java
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.message;
+
+public interface MessageFactoryProvider {
+
+  MessageFactory get(MessageIdentifier messageIdentifier);
+
+  boolean has(MessageIdentifier messageIdentifier);
+}
diff --git a/message_generator/src/main/java/org/ros/message/MessageIdentifier.java b/message_generator/src/main/java/org/ros/message/MessageIdentifier.java
new file mode 100644
index 0000000..9895c39
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/message/MessageIdentifier.java
@@ -0,0 +1,121 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.message;
+
+import com.google.common.base.Preconditions;
+
+/**
+ * Uniquely identifies a message.
+ * 
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class MessageIdentifier {
+
+  private String type;
+  private String pkg;
+  private String name;
+
+  public static MessageIdentifier of(String pkg, String name) {
+    Preconditions.checkNotNull(pkg);
+    Preconditions.checkNotNull(name);
+    return new MessageIdentifier(pkg, name);
+  }
+
+  public static MessageIdentifier of(String type) {
+    Preconditions.checkNotNull(type);
+    // We're not using Preconditions.checkArgument() here because we want a
+    // useful error message without paying the performance penalty of
+    // constructing it every time.
+    if (!type.contains("/")) {
+      throw new IllegalArgumentException(String.format(
+          "Type name is invalid or not fully qualified: \"%s\"", type));
+    }
+    return new MessageIdentifier(type);
+  }
+
+  private MessageIdentifier(String type) {
+    this.type = type;
+  }
+
+  private MessageIdentifier(String pkg, String name) {
+    this.pkg = pkg;
+    this.name = name;
+  }
+
+  public String getType() {
+    if (type == null) {
+      // Using StringBuilder like this is about 40% faster than using the +
+      // operator.
+      StringBuilder stringBuilder = new StringBuilder(pkg.length() + name.length() + 1);
+      stringBuilder.append(pkg);
+      stringBuilder.append("/");
+      stringBuilder.append(name);
+      type = stringBuilder.toString();
+    }
+    return type;
+  }
+
+  private void splitType() {
+    String[] packageAndName = type.split("/", 2);
+    pkg = packageAndName[0];
+    name = packageAndName[1];
+  }
+
+  public String getPackage() {
+    if (pkg == null) {
+      splitType();
+    }
+    return pkg;
+  }
+
+  public String getName() {
+    if (name == null) {
+      splitType();
+    }
+    return name;
+  }
+
+  @Override
+  public String toString() {
+    return String.format("MessageIdentifier<%s>", type);
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = 1;
+    result = prime * result + ((type == null) ? 0 : type.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj)
+      return true;
+    if (obj == null)
+      return false;
+    if (getClass() != obj.getClass())
+      return false;
+    MessageIdentifier other = (MessageIdentifier) obj;
+    if (type == null) {
+      if (other.type != null)
+        return false;
+    } else if (!type.equals(other.type))
+      return false;
+    return true;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/message/MessageListener.java b/message_generator/src/main/java/org/ros/message/MessageListener.java
new file mode 100644
index 0000000..6fa0d1e
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/message/MessageListener.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.message;
+
+/**
+ * A callback for asynchronous message-related operations.
+ * 
+ * @author damonkohler@google.com (Damon Kohler)
+ * 
+ * @param <T>
+ *          the type of message expected
+ */
+public interface MessageListener<T> {
+
+  /**
+   * Called when a new message arrives.
+   * 
+   * @param message
+   *          the new message
+   */
+  void onNewMessage(T message);
+}
\ No newline at end of file
diff --git a/message_generator/src/main/java/org/ros/message/MessageSerializationFactory.java b/message_generator/src/main/java/org/ros/message/MessageSerializationFactory.java
new file mode 100644
index 0000000..8971583
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/message/MessageSerializationFactory.java
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.message;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public interface MessageSerializationFactory {
+
+  /**
+   * @param messageType
+   *          the type of message that the new {@link MessageSerializer} should
+   *          serialize
+   * @return a new {@link MessageSerializer} for the provided message type
+   */
+  <T> MessageSerializer<T> newMessageSerializer(String messageType);
+
+  /**
+   * @param messageType
+   *          the type of message that the new {@link MessageDeserializer}
+   *          should deserialize
+   * @return a new {@link MessageDeserializer} for the provided message type
+   */
+  <T> MessageDeserializer<T> newMessageDeserializer(String messageType);
+
+  /**
+   * @param serviceType
+   *          the type of service that the new {@link MessageSerializer} should
+   *          serialize requests for
+   * @return a new {@link MessageSerializer} for requests to the provided
+   *         service type
+   */
+  <T> MessageSerializer<T> newServiceRequestSerializer(String serviceType);
+
+  /**
+   * @param serviceType
+   *          the type of service that the new {@link MessageDeserializer}
+   *          should deserialize requests for
+   * @return a new {@link MessageDeserializer} for requests to the provided
+   *         service type
+   */
+  <T> MessageDeserializer<T> newServiceRequestDeserializer(String serviceType);
+
+  /**
+   * @param serviceType
+   *          the type of service that the new {@link MessageSerializer} should
+   *          serialize responses for
+   * @return a new {@link MessageSerializer} for responses from the provided
+   *         service type
+   */
+  <T> MessageSerializer<T> newServiceResponseSerializer(String serviceType);
+
+  /**
+   * @param serviceType
+   *          the type of service that the new {@link MessageDeserializer}
+   *          should deserialize responses for
+   * @return a new {@link MessageDeserializer} for responses from the provided
+   *         service type
+   */
+  <T> MessageDeserializer<T> newServiceResponseDeserializer(String serviceType);
+}
diff --git a/message_generator/src/main/java/org/ros/message/MessageSerializer.java b/message_generator/src/main/java/org/ros/message/MessageSerializer.java
new file mode 100644
index 0000000..ffeb218
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/message/MessageSerializer.java
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.ros.message;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ * 
+ * @param <T>
+ *          the type of message that the {@link MessageSerializer} can serialize
+ */
+public interface MessageSerializer<T> {
+
+  void serialize(T message, ChannelBuffer buffer);
+}
diff --git a/message_generator/src/main/java/org/ros/message/Time.java b/message_generator/src/main/java/org/ros/message/Time.java
new file mode 100644
index 0000000..7805610
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/message/Time.java
@@ -0,0 +1,156 @@
+/*
+ * Software License Agreement (BSD License)
+ * 
+ * Copyright (c) 2008, Willow Garage, Inc. All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 
+ * * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer. * Redistributions in binary
+ * form must reproduce the above copyright notice, this list of conditions and
+ * the following disclaimer in the documentation and/or other materials provided
+ * with the distribution. * Neither the name of Willow Garage, Inc. nor the
+ * names of its contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.ros.message;
+
+/**
+ * ROS Time representation. Time and Time are primitive types in ROS. ROS
+ * represents each as two 32-bit integers: seconds and nanoseconds since epoch.
+ * 
+ * @see "http://www.ros.org/wiki/msg"
+ * 
+ * @author Jason Wolfe
+ * @author kwc@willowgarage.com (Ken Conley)
+ */
+public class Time implements Comparable<Time> {
+
+  public int secs;
+  public int nsecs;
+
+  public Time() {
+    secs = 0;
+    nsecs = 0;
+  }
+
+  public Time(int secs, int nsecs) {
+    this.secs = secs;
+    this.nsecs = nsecs;
+    normalize();
+  }
+
+  public Time(double secs) {
+    this.secs = (int) secs;
+    this.nsecs = (int) ((secs - this.secs) * 1000000000);
+    normalize();
+  }
+
+  public Time(Time t) {
+    this.secs = t.secs;
+    this.nsecs = t.nsecs;
+  }
+
+  public Time add(Duration d) {
+    return new Time(secs + d.secs, nsecs + d.nsecs);
+  }
+
+  public Time subtract(Duration d) {
+    return new Time(secs - d.secs, nsecs - d.nsecs);
+  }
+
+  public Duration subtract(Time t) {
+    return new Duration(secs - t.secs, nsecs - t.nsecs);
+  }
+
+  public static Time fromMillis(long timeInMillis) {
+    int secs = (int) (timeInMillis / 1000);
+    int nsecs = (int) (timeInMillis % 1000) * 1000000;
+    return new Time(secs, nsecs);
+  }
+
+  public static Time fromNano(long timeInNs) {
+    int secs = (int) (timeInNs / 1000000000);
+    int nsecs = (int) (timeInNs % 1000000000);
+    return new Time(secs, nsecs);
+  }
+
+  @Override
+  public String toString() {
+    return secs + ":" + nsecs;
+  }
+
+  public double toSeconds() {
+    return totalNsecs() / 1e9;
+  }
+
+  public long totalNsecs() {
+    return ((long) secs) * 1000000000 + nsecs;
+  }
+
+  public boolean isZero() {
+    return totalNsecs() == 0;
+  }
+
+  public void normalize() {
+    while (nsecs < 0) {
+      nsecs += 1000000000;
+      secs -= 1;
+    }
+    while (nsecs >= 1000000000) {
+      nsecs -= 1000000000;
+      secs += 1;
+    }
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = 1;
+    result = prime * result + nsecs;
+    result = prime * result + secs;
+    return result;
+  }
+
+  /**
+   * Check for equality between {@link Time} objects.
+   * <p>
+   * This method does not normalize {@link Time} representations, so fields must match
+   * exactly.
+   */
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj) return true;
+    if (obj == null) return false;
+    if (getClass() != obj.getClass()) return false;
+    Time other = (Time) obj;
+    if (nsecs != other.nsecs) return false;
+    if (secs != other.secs) return false;
+    return true;
+  }
+
+  @Override
+  public int compareTo(Time t) {
+    if ((secs > t.secs) || ((secs == t.secs) && nsecs > t.nsecs)) {
+      return 1;
+    }
+    if ((secs == t.secs) && (nsecs == t.nsecs)) {
+      return 0;
+    }
+    return -1;
+  }
+}
diff --git a/message_generator/src/main/java/org/ros/message/package-info.java b/message_generator/src/main/java/org/ros/message/package-info.java
new file mode 100644
index 0000000..2f57561
--- /dev/null
+++ b/message_generator/src/main/java/org/ros/message/package-info.java
@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2012 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+/**
+ * Provides the classes for representing messages.
+ * 
+ * @see <a href="http://ros.org/wiki/Messages">messages documentation</a>
+ */
+package org.ros.message;
\ No newline at end of file
diff --git a/package.xml b/package.xml
new file mode 100644
index 0000000..db623cb
--- /dev/null
+++ b/package.xml
@@ -0,0 +1,16 @@
+<?xml version="1.0"?>
+<package>
+  <name>rosjava_bootstrap</name>
+  <version>0.1.0</version>
+  <description>
+    Bootstrap utilities for rosjava builds.
+  </description>
+  <url>http://ros.org/wiki/rosjava_bootstrap</url>
+  <maintainer email="d.stonier@gmail.com">Daniel Stonier</maintainer>
+  <author email="d.stonier@gmail.com">Daniel Stonier</author>
+  <author email="damonkohler@google.com">Damon Kohler</author>
+  <license>Apache 2.0</license>
+  <buildtool_depend>catkin</buildtool_depend>
+  <build_depend>rosjava_tools</build_depend>
+</package>
+
diff --git a/settings.gradle b/settings.gradle
index 98689ec..af55cd9 100644
--- a/settings.gradle
+++ b/settings.gradle
@@ -16,4 +16,5 @@
 
 /* rootProject.name = 'catkin' */
 
-include 'rosjava_gradle_plugins'
\ No newline at end of file
+include 'gradle_plugins'
+include 'message_generator'
\ No newline at end of file
-- 
GitLab