Added NtpTimeProvider and renamed WallclockProvider to WallTimeProvider.

Improved error messages from MessageFactory.
Added fromMillis/Nanos to Duration to support NtpTimeProvider.

rosjava/manifest.xml

@@ -31,6 +31,7 @@
     <rosjava-pathelement groupId="com.google.guava" artifactId="org.ros.rosjava.guava" version="r07" />
     <rosjava-pathelement groupId="org.jboss.netty" artifactId="netty" version="3.2.4.Final"  />
     <rosjava-pathelement groupId="org.apache.commons" artifactId="com.springsource.org.apache.commons.logging" version="1.1.1"  />
+    <rosjava-pathelement groupId="commons-net" artifactId="commons-net" version="2.0"  />
 
     <rosjava-pathelement groupId="junit" artifactId="junit" version="4.8.2" scope="test" />
     <rosjava-pathelement groupId="org.mockito" artifactId="mockito-all" version="1.8.5"  scope="test" />

rosjava/src/main/java/org/ros/internal/message/old_style/MessageFactory.java

@@ -16,11 +16,11 @@
 
 package org.ros.internal.message.old_style;
 
+import com.google.common.base.Preconditions;
+
 import org.ros.exception.RosRuntimeException;
 import org.ros.message.Message;
 
-import com.google.common.base.Preconditions;
-
 /**
  * @author damonkohler@google.com (Damon Kohler)
  */
@@ -72,14 +72,12 @@ public class MessageFactory implements org.ros.message.MessageFactory {
    * Get the class for a given message type.
    * 
    * @param messageType
-   *          The string giving "ros package"/"message name", e.g. std_msgs/Time
+   *          the string giving "ros package"/"message name", e.g. std_msgs/Time
    * @param packagePath
-   *          Path to the package which contain messages.
-   * 
-   * @return The class.
-   * 
+   *          path to the package which contain messages
+   * @return the message class
    * @throws RosRuntimeException
-   *           No class representing that name or the class is not accessible.
+   *           no class representing that name or the class is not accessible
    */
   @SuppressWarnings("unchecked")
   private static Class<Message> loadMessageClass(String messageType, String packagePath) {
@@ -88,7 +86,7 @@ public class MessageFactory implements org.ros.message.MessageFactory {
       return (Class<Message>) MessageFactory.class.getClassLoader().loadClass(
           packagePath + "." + messageType.replace('/', '.'));
     } catch (Exception e) {
-      throw new RosRuntimeException(e);
+      throw new RosRuntimeException("Failed to load message type: \"" + messageType + "\"", e);
     }
   }
 }

rosjava/src/main/java/org/ros/node/DefaultNodeRunner.java

@@ -68,7 +68,7 @@ public class DefaultNodeRunner implements NodeRunner {
    */
   @Override
   public void run(final NodeMain nodeMain, final NodeConfiguration nodeConfiguration) {
-    Preconditions.checkNotNull(nodeConfiguration.getNodeName());
+    Preconditions.checkNotNull(nodeConfiguration.getNodeName(), "Node name not specified.");
     executor.execute(new Runnable() {
       @Override
       public void run() {

rosjava/src/main/java/org/ros/node/NodeConfiguration.java

@@ -16,13 +16,14 @@
 
 package org.ros.node;
 
+import org.ros.time.WallTimeProvider;
+
 import org.ros.address.AdvertiseAddress;
 import org.ros.address.AdvertiseAddressFactory;
 import org.ros.address.BindAddress;
 import org.ros.address.PrivateAdvertiseAddressFactory;
 import org.ros.address.PublicAdvertiseAddressFactory;
 import org.ros.exception.RosRuntimeException;
-import org.ros.internal.time.WallclockProvider;
 import org.ros.message.MessageDefinitionFactory;
 import org.ros.message.MessageFactory;
 import org.ros.message.MessageSerializationFactory;
@@ -162,7 +163,7 @@ public class NodeConfiguration {
     setMessageDefinitionFactory(new org.ros.internal.message.old_style.MessageDefinitionFactory());
     setMessageSerializationFactory(new org.ros.internal.message.old_style.MessageSerializationFactory());
     setParentResolver(NameResolver.create());
-    setTimeProvider(new WallclockProvider());
+    setTimeProvider(new WallTimeProvider());
   }
 
   /**
@@ -450,7 +451,7 @@ public class NodeConfiguration {
 
   /**
    * Sets the {@link TimeProvider} that {@link Node}s will use. By default, the
-   * {@link WallclockProvider} is used.
+   * {@link WallTimeProvider} is used.
    * 
    * @param timeProvider
    *          the {@link TimeProvider} that {@link Node}s will use

rosjava/src/main/java/org/ros/time/NtpTimeProvider.java

+/*
+ * 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.time;
+
+import org.apache.commons.net.ntp.NTPUDPClient;
+import org.apache.commons.net.ntp.TimeInfo;
+import org.ros.exception.RosRuntimeException;
+import org.ros.message.Duration;
+import org.ros.message.Time;
+
+import java.io.IOException;
+import java.net.InetAddress;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class NtpTimeProvider implements TimeProvider {
+
+  private final InetAddress host;
+  private final NTPUDPClient ntpClient;
+  private final WallTimeProvider wallTimeProvider;
+
+  private TimeInfo time;
+
+  public NtpTimeProvider(InetAddress host) {
+    this.host = host;
+    this.wallTimeProvider = new WallTimeProvider();
+    ntpClient = new NTPUDPClient();
+  }
+
+  public void updateTime() {
+    try {
+      time = ntpClient.getTime(host);
+    } catch (IOException e) {
+      throw new RosRuntimeException("Failed to read time from NTP server " + host.getHostName(), e);
+    }
+    time.computeDetails();
+  }
+
+  @Override
+  public Time getCurrentTime() {
+    Time currentTime = wallTimeProvider.getCurrentTime();
+    long offset = time.getOffset();
+    return currentTime.add(Duration.fromMillis(offset));
+  }
+
+}

rosjava/src/main/java/org/ros/internal/time/WallclockProvider.java → rosjava/src/main/java/org/ros/time/WallTimeProvider.java

@@ -14,9 +14,8 @@
  * the License.
  */
 
-package org.ros.internal.time;
+package org.ros.time;
 
-import org.ros.time.TimeProvider;
 
 import org.ros.message.Time;
 
@@ -25,7 +24,7 @@ import org.ros.message.Time;
  * 
  * @author kwc@willowgarage.com (Ken Conley)
  */
-public class WallclockProvider implements TimeProvider {
+public class WallTimeProvider implements TimeProvider {
 
   @Override
   public Time getCurrentTime() {

rosjava/src/test/java/org/ros/time/NtpTimeProviderTest.java

+/*
+ * 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.time;
+
+import org.junit.Test;
+import org.ros.address.InetAddressFactory;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+public class NtpTimeProviderTest {
+
+  @Test
+  public void testNtpTime() {
+    // TODO(damonkohler): This is only a simple sanity check.
+    NtpTimeProvider ntpTimeProvider =
+        new NtpTimeProvider(InetAddressFactory.newFromHostString("ntps1-0.cs.tu-berlin.de"));
+    ntpTimeProvider.updateTime();
+    ntpTimeProvider.getCurrentTime();
+  }
+
+}

rosjava_bootstrap/src/main/java/org/ros/message/Duration.java

@@ -48,6 +48,7 @@ package org.ros.message;
 public class Duration implements Comparable<Duration> {
 
   public static final Duration MAX_VALUE = new Duration(Integer.MAX_VALUE, 999999999);
+
   public int secs;
   public int nsecs;
 
@@ -79,6 +80,18 @@ public class Duration implements Comparable<Duration> {
     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;