Add getDefaultNodeName() to NodeMain to support the typical ROS behavior of...

Add getDefaultNodeName() to NodeMain to support the typical ROS behavior of overriding default node names.
Add (almost) proper handling of slaves with the same name attempting to register with the master.
Fix pubsub tutorial.
Some rename cleanup.

actionlib_java/src/tutorials/java/org/ros/actionlib/example/RunFibonacciSimpleActionClient.java

@@ -10,6 +10,7 @@ import org.ros.message.actionlib_tutorials.FibonacciActionResult;
 import org.ros.message.actionlib_tutorials.FibonacciFeedback;
 import org.ros.message.actionlib_tutorials.FibonacciGoal;
 import org.ros.message.actionlib_tutorials.FibonacciResult;
+import org.ros.namespace.GraphName;
 import org.ros.node.DefaultNodeMainExecutor;
 import org.ros.node.Node;
 import org.ros.node.NodeConfiguration;
@@ -38,7 +39,7 @@ public class RunFibonacciSimpleActionClient {
       FibonacciActionSpec spec = new FibonacciActionSpec();
       final FibonacciSimpleActionClient sac = spec.buildSimpleActionClient("fibonacci_client");
 
-      runner.run(new NodeMain() {
+      runner.executeNodeMain(new NodeMain() {
 
         @Override
         public void onStart(Node node) {
@@ -53,6 +54,10 @@ public class RunFibonacciSimpleActionClient {
         public void onShutdownComplete(Node node) {
         }
 
+        @Override
+        public GraphName getDefaultNodeName() {
+          return new GraphName("actionlib_java/fibonacci_client");
+        }
       }, configuration);
 
       System.out.println("[Test] Waiting for action server to start");
@@ -117,7 +122,7 @@ public class RunFibonacciSimpleActionClient {
 
       final SimpleActionClient<FibonacciActionFeedback, FibonacciActionGoal, FibonacciActionResult, FibonacciFeedback, FibonacciGoal, FibonacciResult> sac =
           spec.buildSimpleActionClient("fibonacci");
-      runner.run(new NodeMain() {
+      runner.executeNodeMain(new NodeMain() {
 
         @Override
         public void onStart(Node node) {
@@ -132,6 +137,10 @@ public class RunFibonacciSimpleActionClient {
         public void onShutdownComplete(Node node) {
         }
 
+        @Override
+        public GraphName getDefaultNodeName() {
+          return new GraphName("actionlib_java/fibonacci_client");
+        }
       }, configuration);
 
       System.out.println("[Test] Waiting for action server to start");

actionlib_java/src/tutorials/java/org/ros/actionlib/example/RunFibonacciSimpleActionServer.java

 package org.ros.actionlib.example;
 
+import org.ros.namespace.GraphName;
 import org.ros.node.DefaultNodeMainExecutor;
 import org.ros.node.Node;
 import org.ros.node.NodeConfiguration;
@@ -28,7 +29,7 @@ public class RunFibonacciSimpleActionServer {
 
       NodeMainExecutor runner = DefaultNodeMainExecutor.newDefault();
 
-      runner.run(new NodeMain() {
+      runner.executeNodeMain(new NodeMain() {
 
         @Override
         public void onStart(Node node) {
@@ -43,6 +44,10 @@ public class RunFibonacciSimpleActionServer {
         public void onShutdownComplete(Node node) {
         }
 
+        @Override
+        public GraphName getDefaultNodeName() {
+          throw new UnsupportedOperationException();
+        }
       }, configuration);
     } catch (Exception e) {
       // TODO Auto-generated catch block

rosjava/src/main/java/org/ros/RosRun.java

@@ -67,7 +67,8 @@ public class RosRun {
       throw new RosRuntimeException("Unable to instantiate node: " + nodeClassName, e);
     }
 
+    Preconditions.checkState(nodeMain != null);
     NodeMainExecutor runner = DefaultNodeMainExecutor.newDefault();
-    runner.run(nodeMain, nodeConfiguration);
+    runner.executeNodeMain(nodeMain, nodeConfiguration);
   }
 }

rosjava/src/main/java/org/ros/internal/node/client/Client.java

@@ -16,9 +16,6 @@
 
 package org.ros.internal.node.client;
 
-import java.net.MalformedURLException;
-import java.net.URI;
-
 import org.apache.xmlrpc.client.XmlRpcClient;
 import org.apache.xmlrpc.client.XmlRpcClientConfigImpl;
 import org.apache.xmlrpc.client.XmlRpcCommonsTransportFactory;
@@ -27,6 +24,9 @@ import org.ros.internal.node.server.NodeServer;
 import org.ros.internal.node.xmlrpc.XmlRpcClientFactory;
 import org.ros.internal.node.xmlrpc.XmlRpcEndpoint;
 
+import java.net.MalformedURLException;
+import java.net.URI;
+
 /**
  * Base class for XML-RPC clients (e.g. MasterClient and SlaveClient).
  * 
@@ -45,7 +45,7 @@ abstract class Client<T extends XmlRpcEndpoint> {
 
   private final URI uri;
 
-  protected final T node;
+  protected final T xmlRpcEndpoint;
 
   /**
    * @param uri
@@ -69,7 +69,7 @@ abstract class Client<T extends XmlRpcEndpoint> {
     client.setConfig(config);
 
     XmlRpcClientFactory<T> factory = new XmlRpcClientFactory<T>(client);
-    node =
+    xmlRpcEndpoint =
         interfaceClass.cast(factory.newInstance(getClass().getClassLoader(), interfaceClass, "",
             XMLRPC_TIMEOUT));
   }
@@ -80,5 +80,4 @@ abstract class Client<T extends XmlRpcEndpoint> {
   public URI getRemoteUri() {
     return uri;
   }
-
 }

rosjava/src/main/java/org/ros/internal/node/client/MasterClient.java

@@ -65,7 +65,7 @@ public class MasterClient extends Client<MasterXmlRpcEndpoint> {
    * @return a {@link Response} with a void result
    */
   public Response<Void> registerService(SlaveIdentifier slave, ServiceServer<?, ?> service) {
-    return Response.fromListChecked(node.registerService(slave.getNodeName().toString(), service
+    return Response.fromListChecked(xmlRpcEndpoint.registerService(slave.getNodeName().toString(), service
         .getName().toString(), service.getUri().toString(), slave.getUri().toString()),
         new VoidResultFactory());
   }
@@ -82,7 +82,7 @@ public class MasterClient extends Client<MasterXmlRpcEndpoint> {
    *         result
    */
   public Response<Integer> unregisterService(SlaveIdentifier slave, ServiceServer<?, ?> service) {
-    return Response.fromListChecked(node.unregisterService(slave.getNodeName().toString(), service
+    return Response.fromListChecked(xmlRpcEndpoint.unregisterService(slave.getNodeName().toString(), service
         .getName().toString(), service.getUri().toString()), new IntegerResultFactory());
   }
 
@@ -102,7 +102,7 @@ public class MasterClient extends Client<MasterXmlRpcEndpoint> {
    *         as the result
    */
   public Response<List<URI>> registerSubscriber(SlaveIdentifier slave, Subscriber<?> subscriber) {
-    return Response.fromListChecked(node.registerSubscriber(slave.getNodeName().toString(), subscriber
+    return Response.fromListChecked(xmlRpcEndpoint.registerSubscriber(slave.getNodeName().toString(), subscriber
         .getTopicName().toString(), subscriber.getTopicMessageType(), slave.getUri().toString()),
         new UriListResultFactory());
   }
@@ -118,7 +118,7 @@ public class MasterClient extends Client<MasterXmlRpcEndpoint> {
    *         the result
    */
   public Response<Integer> unregisterSubscriber(SlaveIdentifier slave, Subscriber<?> subscriber) {
-    return Response.fromListChecked(node.unregisterSubscriber(slave.getNodeName().toString(),
+    return Response.fromListChecked(xmlRpcEndpoint.unregisterSubscriber(slave.getNodeName().toString(),
         subscriber.getTopicName().toString(), slave.getUri().toString()),
         new IntegerResultFactory());
   }
@@ -139,7 +139,7 @@ public class MasterClient extends Client<MasterXmlRpcEndpoint> {
     String topicName = publisherDefinition.getTopicName().toString();
     String messageType = publisherDefinition.getTopicMessageType();
     return Response.fromListChecked(
-        node.registerPublisher(slaveName, topicName, messageType, slaveUri),
+        xmlRpcEndpoint.registerPublisher(slaveName, topicName, messageType, slaveUri),
         new UriListResultFactory());
   }
 
@@ -156,7 +156,7 @@ public class MasterClient extends Client<MasterXmlRpcEndpoint> {
     String slaveName = publisherIdentifier.getSlaveName().toString();
     String slaveUri = publisherIdentifier.getSlaveUri().toString();
     String topicName = publisherIdentifier.getTopicName().toString();
-    return Response.fromListChecked(node.unregisterPublisher(slaveName, topicName, slaveUri),
+    return Response.fromListChecked(xmlRpcEndpoint.unregisterPublisher(slaveName, topicName, slaveUri),
         new IntegerResultFactory());
   }
 
@@ -171,7 +171,7 @@ public class MasterClient extends Client<MasterXmlRpcEndpoint> {
    *         as a result
    */
   public Response<URI> lookupNode(SlaveIdentifier slave, String nodeName) {
-    return Response.fromListChecked(node.lookupNode(slave.getNodeName().toString(), nodeName),
+    return Response.fromListChecked(xmlRpcEndpoint.lookupNode(slave.getNodeName().toString(), nodeName),
         new UriResultFactory());
   }
 
@@ -184,7 +184,7 @@ public class MasterClient extends Client<MasterXmlRpcEndpoint> {
    */
   public Response<URI> getUri(SlaveIdentifier slave) {
     return Response
-        .fromListChecked(node.getUri(slave.getNodeName().toString()), new UriResultFactory());
+        .fromListChecked(xmlRpcEndpoint.getUri(slave.getNodeName().toString()), new UriResultFactory());
   }
 
   /**
@@ -199,7 +199,7 @@ public class MasterClient extends Client<MasterXmlRpcEndpoint> {
    */
   public Response<URI> lookupService(SlaveIdentifier slave, String serviceName) {
     return Response.fromListCheckedFailure(
-        node.lookupService(slave.getNodeName().toString(), serviceName), new UriResultFactory());
+        xmlRpcEndpoint.lookupService(slave.getNodeName().toString(), serviceName), new UriResultFactory());
   }
 
   public Response<List<TopicDefinition>> getPublishedTopics(SlaveIdentifier slave, String subgraph) {

rosjava/src/main/java/org/ros/internal/node/client/ParameterClient.java

@@ -60,72 +60,72 @@ public class ParameterClient extends Client<ParameterServerXmlRpcEndpoint> {
   }
 
   public Response<Object> getParam(GraphName parameterName) {
-    return Response.fromListCheckedFailure(node.getParam(nodeName, parameterName.toString()),
+    return Response.fromListCheckedFailure(xmlRpcEndpoint.getParam(nodeName, parameterName.toString()),
         new ObjectResultFactory());
   }
 
   public Response<Void> setParam(GraphName parameterName, Boolean parameterValue) {
     return Response.fromListChecked(
-        node.setParam(nodeName, parameterName.toString(), parameterValue), new VoidResultFactory());
+        xmlRpcEndpoint.setParam(nodeName, parameterName.toString(), parameterValue), new VoidResultFactory());
   }
 
   public Response<Void> setParam(GraphName parameterName, Integer parameterValue) {
     return Response.fromListChecked(
-        node.setParam(nodeName, parameterName.toString(), parameterValue), new VoidResultFactory());
+        xmlRpcEndpoint.setParam(nodeName, parameterName.toString(), parameterValue), new VoidResultFactory());
   }
 
   public Response<Void> setParam(GraphName parameterName, Double parameterValue) {
     return Response.fromListChecked(
-        node.setParam(nodeName, parameterName.toString(), parameterValue), new VoidResultFactory());
+        xmlRpcEndpoint.setParam(nodeName, parameterName.toString(), parameterValue), new VoidResultFactory());
   }
 
   public Response<Void> setParam(GraphName parameterName, String parameterValue) {
     return Response.fromListChecked(
-        node.setParam(nodeName, parameterName.toString(), parameterValue), new VoidResultFactory());
+        xmlRpcEndpoint.setParam(nodeName, parameterName.toString(), parameterValue), new VoidResultFactory());
   }
 
   public Response<Void> setParam(GraphName parameterName, List<?> parameterValue) {
     return Response.fromListChecked(
-        node.setParam(nodeName, parameterName.toString(), parameterValue), new VoidResultFactory());
+        xmlRpcEndpoint.setParam(nodeName, parameterName.toString(), parameterValue), new VoidResultFactory());
   }
 
   public Response<Void> setParam(GraphName parameterName, Map<?, ?> parameterValue) {
     return Response.fromListChecked(
-        node.setParam(nodeName, parameterName.toString(), parameterValue), new VoidResultFactory());
+        xmlRpcEndpoint.setParam(nodeName, parameterName.toString(), parameterValue), new VoidResultFactory());
   }
 
   public Response<GraphName> searchParam(GraphName parameterName) {
     Response<String> response =
-        Response.fromListCheckedFailure(node.searchParam(nodeName, parameterName.toString()),
+        Response.fromListCheckedFailure(xmlRpcEndpoint.searchParam(nodeName, parameterName.toString()),
             new StringResultFactory());
     return new Response<GraphName>(response.getStatusCode(), response.getStatusMessage(),
         new GraphName(response.getResult()));
   }
 
   public Response<Object> subscribeParam(GraphName parameterName) {
-    return Response.fromListChecked(node.subscribeParam(nodeName, slaveIdentifier.getUri()
+    return Response.fromListChecked(xmlRpcEndpoint.subscribeParam(nodeName, slaveIdentifier.getUri()
         .toString(), parameterName.toString()), new ObjectResultFactory());
   }
 
   public Response<Integer> unsubscribeParam(GraphName parameterName) {
     return Response.fromListChecked(
-        node.unsubscribeParam(nodeName, slaveIdentifier.getUri().toString(),
+        xmlRpcEndpoint.unsubscribeParam(nodeName, slaveIdentifier.getUri().toString(),
             parameterName.toString()), new IntegerResultFactory());
   }
 
   public Response<Boolean> hasParam(GraphName parameterName) {
-    return Response.fromListChecked(node.hasParam(nodeName, parameterName.toString()),
+    return Response.fromListChecked(xmlRpcEndpoint.hasParam(nodeName, parameterName.toString()),
         new BooleanResultFactory());
   }
 
   public Response<Void> deleteParam(GraphName parameterName) {
-    return Response.fromListChecked(node.deleteParam(nodeName, parameterName.toString()),
+    return Response.fromListChecked(xmlRpcEndpoint.deleteParam(nodeName, parameterName.toString()),
         new VoidResultFactory());
   }
 
   public Response<List<GraphName>> getParamNames() {
     Response<List<String>> response =
-        Response.fromListChecked(node.getParamNames(nodeName), new StringListResultFactory());
+        Response.fromListChecked(xmlRpcEndpoint.getParamNames(nodeName), new StringListResultFactory());
     List<GraphName> graphNames = Lists.newArrayList();
     for (String name : response.getResult()) {
       graphNames.add(new GraphName(name));

rosjava/src/main/java/org/ros/internal/node/client/SlaveClient.java

@@ -16,10 +16,7 @@
 
 package org.ros.internal.node.client;
 
-import java.net.URI;
-import java.util.Collection;
-import java.util.List;
-import java.util.Map;
+import com.google.common.collect.Lists;
 
 import org.ros.internal.node.response.IntegerResultFactory;
 import org.ros.internal.node.response.ProtocolDescriptionResultFactory;
@@ -32,7 +29,10 @@ import org.ros.internal.node.xmlrpc.SlaveXmlRpcEndpoint;
 import org.ros.internal.transport.ProtocolDescription;
 import org.ros.namespace.GraphName;
 
-import com.google.common.collect.Lists;
+import java.net.URI;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
 
 /**
  * @author damonkohler@google.com (Damon Kohler)
@@ -55,59 +55,59 @@ public class SlaveClient extends Client<SlaveXmlRpcEndpoint> {
   }
 
   public Response<URI> getMasterUri() {
-    return Response.fromListChecked(node.getMasterUri(nodeName.toString()), new UriResultFactory());
+    return Response.fromListChecked(xmlRpcEndpoint.getMasterUri(nodeName.toString()), new UriResultFactory());
   }
 
-  public List<Object> shutdown(String message) {
-    throw new UnsupportedOperationException();
+  public Response<Void> shutdown(String message) {
+    return Response.fromListChecked(xmlRpcEndpoint.shutdown("/master", message), new VoidResultFactory());
   }
 
   public Response<Integer> getPid() {
-    return Response.fromListChecked(node.getPid(nodeName.toString()), new IntegerResultFactory());
+    return Response.fromListChecked(xmlRpcEndpoint.getPid(nodeName.toString()), new IntegerResultFactory());
   }
 
   public Response<List<TopicDefinition>> getSubscriptions() {
-    return Response.fromListChecked(node.getSubscriptions(nodeName.toString()),
+    return Response.fromListChecked(xmlRpcEndpoint.getSubscriptions(nodeName.toString()),
         new TopicDefinitionListResultFactory());
   }
 
   public Response<List<TopicDefinition>> getPublications() {
-    return Response.fromListChecked(node.getPublications(nodeName.toString()),
+    return Response.fromListChecked(xmlRpcEndpoint.getPublications(nodeName.toString()),
         new TopicDefinitionListResultFactory());
   }
 
   public Response<Void> paramUpdate(GraphName name, boolean value) {
-    return Response.fromListChecked(node.paramUpdate(nodeName.toString(), name.toString(), value),
+    return Response.fromListChecked(xmlRpcEndpoint.paramUpdate(nodeName.toString(), name.toString(), value),
         new VoidResultFactory());
   }
 
   public Response<Void> paramUpdate(GraphName name, char value) {
-    return Response.fromListChecked(node.paramUpdate(nodeName.toString(), name.toString(), value),
+    return Response.fromListChecked(xmlRpcEndpoint.paramUpdate(nodeName.toString(), name.toString(), value),
         new VoidResultFactory());
   }
 
   public Response<Void> paramUpdate(GraphName name, int value) {
-    return Response.fromListChecked(node.paramUpdate(nodeName.toString(), name.toString(), value),
+    return Response.fromListChecked(xmlRpcEndpoint.paramUpdate(nodeName.toString(), name.toString(), value),
         new VoidResultFactory());
   }
 
   public Response<Void> paramUpdate(GraphName name, double value) {
-    return Response.fromListChecked(node.paramUpdate(nodeName.toString(), name.toString(), value),
+    return Response.fromListChecked(xmlRpcEndpoint.paramUpdate(nodeName.toString(), name.toString(), value),
         new VoidResultFactory());
   }
 
   public Response<Void> paramUpdate(GraphName name, String value) {
-    return Response.fromListChecked(node.paramUpdate(nodeName.toString(), name.toString(), value),
+    return Response.fromListChecked(xmlRpcEndpoint.paramUpdate(nodeName.toString(), name.toString(), value),
         new VoidResultFactory());
   }
 
   public Response<Void> paramUpdate(GraphName name, List<?> value) {
-    return Response.fromListChecked(node.paramUpdate(nodeName.toString(), name.toString(), value),
+    return Response.fromListChecked(xmlRpcEndpoint.paramUpdate(nodeName.toString(), name.toString(), value),
         new VoidResultFactory());
   }
 
   public Response<Void> paramUpdate(GraphName name, Map<?, ?> value) {
-    return Response.fromListChecked(node.paramUpdate(nodeName.toString(), name.toString(), value),
+    return Response.fromListChecked(xmlRpcEndpoint.paramUpdate(nodeName.toString(), name.toString(), value),
         new VoidResultFactory());
   }
 
@@ -117,14 +117,13 @@ public class SlaveClient extends Client<SlaveXmlRpcEndpoint> {
       publishers.add(uri.toString());
     }
     return Response.fromListChecked(
-        node.publisherUpdate(nodeName.toString(), topic.toString(), publishers.toArray()),
+        xmlRpcEndpoint.publisherUpdate(nodeName.toString(), topic.toString(), publishers.toArray()),
         new VoidResultFactory());
   }
 
   public Response<ProtocolDescription> requestTopic(GraphName topic,
       Collection<String> requestedProtocols) {
-    return Response.fromListChecked(node.requestTopic(nodeName.toString(), topic.toString(),
+    return Response.fromListChecked(xmlRpcEndpoint.requestTopic(nodeName.toString(), topic.toString(),
         new Object[][] { requestedProtocols.toArray() }), new ProtocolDescriptionResultFactory());
   }
-
 }

rosjava/src/main/java/org/ros/internal/node/server/MasterServer.java

@@ -162,9 +162,12 @@ public class MasterServer extends NodeServer {
   private void addSlave(SlaveIdentifier slaveIdentifier) {
     Preconditions.checkNotNull(slaveIdentifier);
     GraphName slaveName = slaveIdentifier.getNodeName();
-    Preconditions.checkState(
-        slaves.get(slaveName) == null || slaves.get(slaveName).equals(slaveIdentifier),
-        "Failed to add slave: " + slaveIdentifier + "\nExisting slave: " + slaves.get(slaveName));
+    SlaveIdentifier existingSlaveIdentifier = slaves.get(slaveName);
+    if (existingSlaveIdentifier != null && !existingSlaveIdentifier.equals(slaveIdentifier)) {
+      log.warn(String.format("Existing slave %s will be shutdown.", existingSlaveIdentifier));
+      SlaveClient client = new SlaveClient(MASTER_NODE_NAME, existingSlaveIdentifier.getUri());
+      client.shutdown(String.format("Replaced by slave %s.", slaveIdentifier));
+    }
     slaves.put(slaveName, slaveIdentifier);
   }
 

rosjava/src/main/java/org/ros/internal/node/server/SlaveServer.java

@@ -80,10 +80,12 @@ public class SlaveServer extends NodeServer {
    * correct information when topics are requested.
    */
   public void start() {
-    super.start(org.ros.internal.node.xmlrpc.SlaveXmlRpcEndpointImpl.class, new SlaveXmlRpcEndpointImpl(this));
+    super.start(org.ros.internal.node.xmlrpc.SlaveXmlRpcEndpointImpl.class,
+        new SlaveXmlRpcEndpointImpl(this));
     tcpRosServer.start();
   }
 
+  // TODO(damonkohler): This should also shut down the Node.
   @Override
   public void shutdown() {
     super.shutdown();

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

@@ -97,15 +97,16 @@ public class DefaultNodeMainExecutor implements NodeMainExecutor {
   }
 
   @Override
-  public void run(final NodeMain nodeMain, final NodeConfiguration nodeConfiguration,
+  public void executeNodeMain(final NodeMain nodeMain, final NodeConfiguration nodeConfiguration,
       final Collection<NodeListener> nodeListeners) {
-    Preconditions.checkNotNull(nodeConfiguration.getNodeName(), "Node name not specified.");
-    if (DEBUG) {
-      log.info("Starting node: " + nodeConfiguration.getNodeName());
-    }
-    // NOTE(damonkohler): To avoid a race condition, we have to make a copy
+    // NOTE(damonkohler): To avoid a race condition, we have to make our copy
     // of the NodeConfiguration in the current thread.
     final NodeConfiguration nodeConfigurationCopy = NodeConfiguration.copyOf(nodeConfiguration);
+    nodeConfigurationCopy.setDefaultNodeName(nodeMain.getDefaultNodeName());
+    Preconditions.checkNotNull(nodeConfigurationCopy.getNodeName(), "Node name not specified.");
+    if (DEBUG) {
+      log.info("Starting node: " + nodeConfigurationCopy.getNodeName());
+    }
     executorService.execute(new Runnable() {
       @Override
       public void run() {
@@ -123,8 +124,8 @@ public class DefaultNodeMainExecutor implements NodeMainExecutor {
   }
 
   @Override
-  public void run(NodeMain nodeMain, NodeConfiguration nodeConfiguration) {
-    run(nodeMain, nodeConfiguration, null);
+  public void executeNodeMain(NodeMain nodeMain, NodeConfiguration nodeConfiguration) {
+    executeNodeMain(nodeMain, nodeConfiguration, null);
   }
 
   @Override

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

@@ -16,18 +16,27 @@
 
 package org.ros.node;
 
+import org.ros.namespace.GraphName;
 import org.ros.node.topic.Publisher;
 import org.ros.node.topic.Subscriber;
 
 /**
- * The one required {@link NodeListener} for node creation.
+ * Encapsulates a {@link Node} with its associated program logic.
  * 
  * <p>
- * {@link NodeListener#onStart(Node)} should be used to set up your program's
- * {@link Publisher}s, {@link Subscriber}s, and services.
+ * {@link NodeMain} is the one required {@link NodeListener} for {@link Node}
+ * creation. {@link NodeListener#onStart(Node)} should be used to set up your
+ * program's {@link Publisher}s, {@link Subscriber}s, etc.
  * 
  * @author ethan.rublee@gmail.com (Ethan Rublee)
  * @author damonkohler@google.com (Damon Kohler)
  */
 public interface NodeMain extends NodeListener {
+
+  /**
+   * @return the name of the {@link Node} that will be used if a name was not
+   *         specified in the {@link Node}'s associated
+   *         {@link NodeConfiguration}
+   */
+  GraphName getDefaultNodeName();
 }

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

@@ -20,7 +20,8 @@ import java.util.Collection;
 import java.util.concurrent.ExecutorService;
 
 /**
- * Executes {@link NodeMain}s.
+ * Executes {@link NodeMain}s and allows shutting down individual
+ * {@link NodeMain}s or all currently running {@link NodeMain}s as a group.
  * 
  * @author damonkohler@google.com (Damon Kohler)
  */
@@ -37,9 +38,9 @@ public interface NodeMainExecutor {
    *          {@link Node}
    * @param nodeListeners
    *          a {@link Collection} of {@link NodeListener}s to be added to the
-   *          {@link Node} before it starts (can be {@code null})
+   *          {@link Node} before it starts, can be {@code null}
    */
-  void run(NodeMain nodeMain, NodeConfiguration nodeConfiguration,
+  void executeNodeMain(NodeMain nodeMain, NodeConfiguration nodeConfiguration,
       Collection<NodeListener> nodeListeners);
 
   /**
@@ -52,7 +53,7 @@ public interface NodeMainExecutor {
    *          the {@link NodeConfiguration} that will be used to create the
    *          {@link Node}
    */
-  void run(NodeMain nodeMain, NodeConfiguration nodeConfiguration);
+  void executeNodeMain(NodeMain nodeMain, NodeConfiguration nodeConfiguration);
 
   /**
    * Executes a {@link Runnable} using this {@link NodeMainExecutor}'s

rosjava/src/test/java/org/ros/ParameterServerTestNode.java

@@ -41,6 +41,11 @@ import java.util.Map;
  */
 public class ParameterServerTestNode implements NodeMain {
 
+  @Override
+  public GraphName getDefaultNodeName() {
+    return new GraphName("rosjava/parameter_server_test_node");
+  }
+
   @SuppressWarnings("rawtypes")
   @Override
   public void onStart(Node node) {

rosjava/src/test/java/org/ros/PassthroughTestNode.java

@@ -17,6 +17,7 @@
 package org.ros;
 
 import org.ros.message.MessageListener;
+import org.ros.namespace.GraphName;
 import org.ros.node.Node;
 import org.ros.node.NodeMain;
 import org.ros.node.topic.Publisher;
@@ -30,6 +31,11 @@ import org.ros.node.topic.Subscriber;
  */
 public class PassthroughTestNode implements NodeMain {
 
+  @Override
+  public GraphName getDefaultNodeName() {
+    return new GraphName("rosjava/passthrough_test_node");
+  }
+
   @Override
   public void onStart(final Node node) {
     // The goal of the passthrough node is simply to retransmit the messages

rosjava/src/test/java/org/ros/SlaveApiTestNode.java

@@ -19,6 +19,7 @@ package org.ros;
 import org.ros.concurrent.CancellableLoop;
 import org.ros.message.MessageListener;
 import org.ros.message.std_msgs.Int64;
+import org.ros.namespace.GraphName;
 import org.ros.node.Node;
 import org.ros.node.NodeMain;
 import org.ros.node.topic.Publisher;
@@ -31,6 +32,11 @@ import org.ros.node.topic.Subscriber;
  */
 public class SlaveApiTestNode implements NodeMain {
 
+  @Override
+  public GraphName getDefaultNodeName() {
+    return new GraphName("rosjava/slave_api_test_node");
+  }
+
   @Override
   public void onStart(Node node) {
     // Basic chatter in/out test.

rosjava_tutorial_pubsub/src/main/java/org/ros/tutorials/pubsub/Listener.java

@@ -18,6 +18,7 @@ package org.ros.tutorials.pubsub;
 
 import org.apache.commons.logging.Log;
 import org.ros.message.MessageListener;
+import org.ros.namespace.GraphName;
 import org.ros.node.Node;
 import org.ros.node.NodeMain;
 import org.ros.node.topic.Subscriber;
@@ -30,6 +31,11 @@ import org.ros.node.topic.Subscriber;
  */
 public class Listener implements NodeMain {
 
+  @Override
+  public GraphName getDefaultNodeName() {
+    return new GraphName("rosjava_tutorial_pubsub/listener");
+  }
+
   @Override
   public void onStart(Node node) {
     final Log log = node.getLog();

rosjava_tutorial_pubsub/src/main/java/org/ros/tutorials/pubsub/Talker.java

@@ -16,46 +16,47 @@
 
 package org.ros.tutorials.pubsub;
 
-import com.google.common.base.Preconditions;
-
+import org.ros.concurrent.CancellableLoop;
+import org.ros.namespace.GraphName;
 import org.ros.node.Node;
 import org.ros.node.NodeMain;
 import org.ros.node.topic.Publisher;
 
 /**
- * This is a simple rosjava {@link Publisher} {@link Node}. It assumes an
- * external roscore is already running.
+ * A simple {@link Publisher} {@link Node}.
  * 
- * @author ethan.rublee@gmail.com (Ethan Rublee)
  * @author damonkohler@google.com (Damon Kohler)
  */
 public class Talker implements NodeMain {
 
-  private Node node;
+  @Override
+  public GraphName getDefaultNodeName() {
+    return new GraphName("rosjava_tutorial_pubsub/talker");
+  }
 
   @Override
-  public void onStart(Node node) {
-    Preconditions.checkState(this.node == null);
-    this.node = node;
-    try {
-      Publisher<org.ros.message.std_msgs.String> publisher =
+  public void onStart(final Node node) {
+    final Publisher<org.ros.message.std_msgs.String> publisher =
         node.newPublisher("chatter", "std_msgs/String");
-      int seq = 0;
-      while (true) {
+    // This CancellableLoop will be canceled automatically when the Node shuts
+    // down.
+    node.executeCancellableLoop(new CancellableLoop() {
+      private int sequenceNumber;
+
+      @Override
+      protected void setup() {
+        sequenceNumber = 0;
+      }
+
+      @Override
+      protected void loop() throws InterruptedException {
         org.ros.message.std_msgs.String str = new org.ros.message.std_msgs.String();
-        str.data = "Hello world! " + seq;
+        str.data = "Hello world! " + sequenceNumber;
         publisher.publish(str);
-        node.getLog().info("Hello, world! " + seq);
-        seq++;
+        sequenceNumber++;
         Thread.sleep(1000);
       }
-    } catch (Exception e) {
-      if (node != null) {
-        node.getLog().fatal(e);
-      } else {
-        e.printStackTrace();
-      }
-    }
+    });
   }
 
   @Override