Added option to specify transport hints.

* Added TransportHints class, currently only containing a TCP-NO-DELAY option.
* Added option to specify transport hints when subscribing to a topic.
* Added transport hints to TopicDeclaration class.

Author: StefanGlaser

rosjava/src/main/java/org/ros/internal/node/DefaultNode.java

@@ -65,6 +65,7 @@
 import org.ros.node.topic.DefaultSubscriberListener;
 import org.ros.node.topic.Publisher;
 import org.ros.node.topic.Subscriber;
+import org.ros.node.topic.TransportHints;
 import org.ros.time.ClockTopicTimeProvider;
 import org.ros.time.TimeProvider;
 
@@ -283,7 +284,7 @@ public <T> Publisher<T> newPublisher(GraphName topicName, String messageType) {
     TopicDescription topicDescription =
         nodeConfiguration.getTopicDescriptionFactory().newFromType(messageType);
     TopicDeclaration topicDeclaration =
-        TopicDeclaration.newFromTopicName(resolvedTopicName, topicDescription);
+        TopicDeclaration.newFromTopicName(resolvedTopicName, topicDescription, null);
     org.ros.message.MessageSerializer<T> serializer = newMessageSerializer(messageType);
     return publisherFactory.newOrExisting(topicDeclaration, serializer);
   }
@@ -295,19 +296,29 @@ public <T> Publisher<T> newPublisher(String topicName, String messageType) {
 
   @Override
   public <T> Subscriber<T> newSubscriber(GraphName topicName, String messageType) {
+    return newSubscriber(topicName, messageType, null);
+  }
+
+  @Override
+  public <T> Subscriber<T> newSubscriber(GraphName topicName, String messageType, TransportHints transportHints) {
     GraphName resolvedTopicName = resolveName(topicName);
     TopicDescription topicDescription =
         nodeConfiguration.getTopicDescriptionFactory().newFromType(messageType);
     TopicDeclaration topicDeclaration =
-        TopicDeclaration.newFromTopicName(resolvedTopicName, topicDescription);
+        TopicDeclaration.newFromTopicName(resolvedTopicName, topicDescription, transportHints);
     MessageDeserializer<T> deserializer = newMessageDeserializer(messageType);
     Subscriber<T> subscriber = subscriberFactory.newOrExisting(topicDeclaration, deserializer);
     return subscriber;
   }
 
   @Override
   public <T> Subscriber<T> newSubscriber(String topicName, String messageType) {
-    return newSubscriber(GraphName.of(topicName), messageType);
+    return newSubscriber(GraphName.of(topicName), messageType, null);
+  }
+
+  @Override
+  public <T> Subscriber<T> newSubscriber(String topicName, String messageType, TransportHints transportHints) {
+    return newSubscriber(GraphName.of(topicName), messageType, transportHints);
   }
 
   @Override

rosjava/src/main/java/org/ros/internal/node/response/TopicListResultFactory.java

@@ -43,7 +43,7 @@ public List<TopicDeclaration> newFromValue(Object value) {
       String name = (String) ((Object[]) topic)[0];
       String type = (String) ((Object[]) topic)[1];
       descriptions.add(TopicDeclaration.newFromTopicName(GraphName.of(name), new TopicDescription(type, null,
-          null)));
+          null), null));
     }
     return descriptions;
   }

rosjava/src/main/java/org/ros/internal/node/topic/TopicDeclaration.java

@@ -23,6 +23,7 @@
 import org.ros.internal.transport.ConnectionHeader;
 import org.ros.internal.transport.ConnectionHeaderFields;
 import org.ros.namespace.GraphName;
+import org.ros.node.topic.TransportHints;
 
 import java.util.List;
 import java.util.Map;
@@ -36,6 +37,7 @@ public class TopicDeclaration {
 
   private final TopicIdentifier topicIdentifier;
   private final TopicDescription topicDescription;
+  private final TransportHints transportHints;
 
   /**
    * @param header
@@ -49,19 +51,26 @@ public static TopicDeclaration newFromHeader(Map<String, String> header) {
     String definition = header.get(ConnectionHeaderFields.MESSAGE_DEFINITION);
     String md5Checksum = header.get(ConnectionHeaderFields.MD5_CHECKSUM);
     TopicDescription topicDescription = new TopicDescription(type, definition, md5Checksum);
-    return new TopicDeclaration(new TopicIdentifier(name), topicDescription);
+    boolean tcpNoDelay = "1".equals(header.get(ConnectionHeaderFields.TCP_NODELAY));
+    return new TopicDeclaration(new TopicIdentifier(name), topicDescription, new TransportHints(tcpNoDelay));
   }
 
   public static TopicDeclaration newFromTopicName(GraphName topicName,
-      TopicDescription topicDescription) {
-    return new TopicDeclaration(new TopicIdentifier(topicName), topicDescription);
+      TopicDescription topicDescription, TransportHints transportHints) {
+    return new TopicDeclaration(new TopicIdentifier(topicName), topicDescription, transportHints);
   }
 
-  public TopicDeclaration(TopicIdentifier topicIdentifier, TopicDescription topicDescription) {
+  public TopicDeclaration(TopicIdentifier topicIdentifier, TopicDescription topicDescription, TransportHints transportHints) {
     Preconditions.checkNotNull(topicIdentifier);
     Preconditions.checkNotNull(topicDescription);
     this.topicIdentifier = topicIdentifier;
     this.topicDescription = topicDescription;
+
+    if (transportHints != null) {
+      this.transportHints = transportHints;
+    } else {
+      this.transportHints = new TransportHints();
+    }
   }
 
   public TopicIdentifier getIdentifier() {
@@ -84,6 +93,7 @@ public ConnectionHeader toConnectionHeader() {
         topicDescription.getDefinition());
     connectionHeader.addField(ConnectionHeaderFields.MD5_CHECKSUM,
         topicDescription.getMd5Checksum());
+    connectionHeader.addField(ConnectionHeaderFields.TCP_NODELAY, transportHints.getTcpNoDelay() ? "1" : "0");
     return connectionHeader;
   }
 

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

@@ -26,6 +26,7 @@
 import org.ros.node.service.ServiceServer;
 import org.ros.node.topic.Publisher;
 import org.ros.node.topic.Subscriber;
+import org.ros.node.topic.TransportHints;
 
 import java.net.URI;
 
@@ -82,11 +83,29 @@ public interface ConnectedNode extends Node {
    */
   <T> Subscriber<T> newSubscriber(GraphName topicName, String messageType);
 
+  /**
+   * @param <T>
+   *          the message type to create the {@link Subscriber} for
+   * @param topicName
+   *          the topic name to be subscribed to, this will be auto resolved
+   * @param messageType
+   *          the message data type (e.g. "std_msgs/String")
+   * @param transportHints
+   *          the transport hints
+   * @return a {@link Subscriber} for the specified topic
+   */
+  <T> Subscriber<T> newSubscriber(GraphName topicName, String messageType, TransportHints transportHints);
+
   /**
    * @see #newSubscriber(GraphName, String)
    */
   <T> Subscriber<T> newSubscriber(String topicName, String messageType);
 
+  /**
+   * @see #newSubscriber(GraphName, String, TransportHints)
+   */
+  <T> Subscriber<T> newSubscriber(String topicName, String messageType, TransportHints transportHints);
+
   /**
    * Create a new {@link ServiceServer}.
    * 

rosjava/src/main/java/org/ros/node/topic/TransportHints.java

@@ -0,0 +1,43 @@
+package org.ros.node.topic;
+
+import java.util.Map;
+
+import org.ros.internal.transport.ConnectionHeaderFields;
+import org.ros.node.ConnectedNode;
+
+import com.google.common.collect.Maps;
+
+
+/**
+ * Provides a way of specifying network transport hints to
+ * {@link ConnectedNode#newSubscriber(String, String)} and
+ * {@link ConnectedNode#newSubscriber(org.ros.namespace.GraphName, String)}.
+ *
+ * @author [email protected] (Stefan Glaser)
+ */
+public class TransportHints {
+
+  Map<String, String> options;
+
+ public TransportHints() {
+   this.options = Maps.newConcurrentMap();
+  }
+
+  public TransportHints(boolean tcpNoDelay) {
+    tcpNoDelay(tcpNoDelay);
+  }
+
+  public TransportHints tcpNoDelay(boolean nodelay) {
+    options.put(ConnectionHeaderFields.TCP_NODELAY, nodelay ? "1" : "0");
+
+    return this;
+  }
+
+  public boolean getTcpNoDelay() {
+    return "1".equals(options.get(ConnectionHeaderFields.TCP_NODELAY));
+  }
+
+  public Map<String, String> getOptions() {
+    return options;
+  }
+}