[ros-users] rosjava Exception if create two Nodes with same name

[Nicholas Butko]

ROS nodes must have unique names. Two start two nodes of the same type in
c++, you would use the command line arguments to set the name of the nodes,
which would override the default.

I'm not sure if this command line argument name remapping was implemented in
java, but if it wasn't, you may consider having java append a random number
to the end of the node name.

--Nick

On Tue, Jun 21, 2011 at 10:33 AM, Abhishek Verma
<toabhishekverma at gmail.com>wrote:

> Hi Friends,
>
> I am seeing following exception
>
> 21-Jun-2011 18:29:01 org.apache.xmlrpc.server.XmlRpcErrorLogger log
> SEVERE: Failed to invoke method registerSubscriber in class
> org.ros.internal.node.xmlrpc.MasterImpl: null
> org.apache.xmlrpc.common.XmlRpcInvocationException: Failed to invoke method
> registerSubscriber in class org.ros.internal.node.xmlrpc.MasterImpl: null
> at
> org.apache.xmlrpc.server.ReflectiveXmlRpcHandler.invoke(ReflectiveXmlRpcHandler.java:129)
>  at
> org.apache.xmlrpc.server.ReflectiveXmlRpcHandler.execute(ReflectiveXmlRpcHandler.java:106)
> at
> org.apache.xmlrpc.server.XmlRpcServerWorker.execute(XmlRpcServerWorker.java:46)
>  at org.apache.xmlrpc.server.XmlRpcServer.execute(XmlRpcServer.java:86)
> at
> org.apache.xmlrpc.server.XmlRpcStreamServer.execute(XmlRpcStreamServer.java:200)
>  at org.apache.xmlrpc.webserver.Connection.run(Connection.java:208)
> at org.apache.xmlrpc.util.ThreadPool$Poolable$1.run(ThreadPool.java:68)
> Caused by: java.lang.IllegalStateException
> at com.google.common.base.Preconditions.checkState(Preconditions.java:129)
> at org.ros.internal.node.server.MasterServer.addSlave(MasterServer.java:80)
>  at
> org.ros.internal.node.server.MasterServer.registerSubscriber(MasterServer.java:110)
> at
> org.ros.internal.node.xmlrpc.MasterImpl.registerSubscriber(MasterImpl.java:123)
>  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
>  at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:597)
>  at
> org.apache.xmlrpc.server.ReflectiveXmlRpcHandler.invoke(ReflectiveXmlRpcHandler.java:115)
>
>
> My code is
>
> //Publisher
> node = new Node("Camera1", configuration);
> publisher = node.createPublisher("Camera1",
>  org.ros.message.sensor_msgs.Image.class);
> ....................
>
> //Subscriber
>  node = new Node("Camera1", configuration);
>       System.out.println("ScreenView.main() Starting");
> //      final Log log = node.getLog();
>       node.createSubscriber("Camera1", new
> MessageListener<org.ros.message.sensor_msgs.Image>() {
>         public void onNewMessage(org.ros.message.sensor_msgs.Image message)
> {
>           System.out
> .println("Subscriber \"" + message + "\"");
>         }
>       }, org.ros.message.sensor_msgs.Image.class);
>
>
> Reason behind this exception is Nodes with same name.
> If I change this name and create different nodes in publisher and
> subscribers code then its fine.
>
> Anyone has any idea why is that or we are not supposed to create node with
> same name?
>
> Thanks and Regards
> Abhishek Verma
>
> _______________________________________________
> ros-users mailing list
> ros-users at code.ros.org
> https://code.ros.org/mailman/listinfo/ros-users
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ros.org/pipermail/ros-users/attachments/20110621/63786799/attachment-0002.html>