6 Replies Latest reply on Jun 27, 2012 6:12 AM by paul.berry

Virtual topics in camel / activemq

paul.berry Jun 25, 2012 10:56 AM

I'm having some problems with virtual topics in Fuse ESB. From the (little) documentation I've been able to find, all I need to do to use a virtual topic is to send messages to it using the following naming convention:

VirtualTopic.mytopicname

and consume the messages using:

Consumer.myconsumername.VirtualTopic.mytopicname

However, if I monitor the created queues (using the activemq web console) I just see two separate queues (VirtualTopic.mytopicname and

Consumer.myconsumername.VirtualTopic.mytopicname) whch don't seem to have any linkage between them. IE: messages pushed into 'VirtualTopic.mytopicname' just sit in that queue and don't get consumed by the consumer or moved into the 'Consumer.myconsumername.VirtualTopic.mytopicname' queue.

So, what am I doing wrong here? I'm sure it's something incredibly obvious...

1. Re: Virtual topics in camel / activemq

garytully Jun 25, 2012 11:32 AM (in response to paul.berry)

That looks correct:

A great reference for working code is always the tests.
For a simple virtual topic test see: http://svn.apache.org/viewvc/activemq/trunk/activemq-core/src/test/java/org/apache/activemq/broker/virtual/VirtualTopicPubSubTest.java?view=markup

The producer sends to: VirtualTopic.TEST
the consumer consumes from: Consumer.A.VirtualTopic.TEST

The caveat is that the consumer needs to be created before the producer so that the matching consumer queue exists when the virtual topic filter on send gets to do its work.

Is there any chance that "useVirtualTopics=false" on the broker element in xml configuration, that would disable the virtual topic feature?
Actions
2. Re: Virtual topics in camel / activemq

paul.berry Jun 25, 2012 11:59 AM (in response to garytully)

I'll take a look at the tests now, cheers.

By saying the consumers have to be created before the publisher, does that mean that I can't dynamically add consumers at runtime?

I just tried again but making sure the consumer was created first, same result.. all messages pushed onto the virtual topic sit there, they never go to the consumer queue.
Actions
3. Re: Virtual topics in camel / activemq

garytully Jun 25, 2012 12:00 PM (in response to paul.berry)

you can dynamically add consumers, but they won't be retrospective. They will just get messages that arrive after their subscription.
Actions
4. Re: Virtual topics in camel / activemq

paul.berry Jun 25, 2012 12:21 PM (in response to garytully)

That's fine, I wouldn't expect to get old messages...I'd expect to get messages from when the consumer is created though!

So, just to clarify I should be able to create a queue with the id of:

VirtualTopic.mytopicname

then create consumer queues like:

Consumer.myconsumername1.VirtualTopic.mytopicname

and when a message is pushed into the VirtualTopic I should see it go to the consumer queues as well?
Actions
5. Re: Virtual topics in camel / activemq

garytully Jun 27, 2012 6:10 AM (in response to paul.berry)
paul.berry wrote:
So, just to clarify I should be able to create a queue with the id of:

VirtualTopic.mytopicname

you should be able to create a topic with that name.
Actions
6. Re: Virtual topics in camel / activemq

paul.berry Jun 27, 2012 6:12 AM (in response to garytully)

Yes.... that was sort of the problem. The guy who wrote the route that was pushing stuff into the topic had used 'queue' instead of 'topic'... hence all the problems I was having :/

Thanks for the help
Actions

Go to original post