Consume messages from multiple queues over single session

[mateusz.gajewski]

Is it possible to consume messages from multiple queues without using multiple sessions/message consumers instances?

ActiveMQ has something called "composite destinations" that does that. I want to create some generic consumer that attaches itself to different queues, receives messages and process them. Number of queues will be quite huge (over 50-100 different kind of messages).

[clebert.suconic]

Take a look on Topic Hierarchy example. Is that what you're looking for?

[clebert.suconic]

BTW: Topic Hierarchy should definitely be what you're looking for.

You create a subscription from multiple queues using wildcards and receive messages on it.

[mateusz.gajewski]

As I understand JMS: topic is not a queue. Topic is rather "broadcast" channel where multiple consumers gets the same piece of information (unlike queue when message is consumed by one subscriber).

Also in documentation there's no information where can I use wildcards:

i.e. ClientConsumer createConsumer(String queueName,                              String filter,                              int windowSize,                              int maxRate,                              boolean browseOnly)                              throws HornetQException

queueName - name of the queue to consume messages from

There's also no information that topic hierarchy is implemented as queues hierarchy (no info in doc or apidoc)

[clebert.suconic]

You would need to create a Queue with a wildcard. I'm not sure now if it would work with jms.queues. I believe it should, but I would need to check.

May Andy Taylor will know on top of his head as he worked on it. If he doesn't know I will look tomorrow.

You will basically have to create a queue (temporary or not), and then you will have to consume of it.

[mateusz.gajewski]

I figured out that by creating queue with wilcard adress (using core API) I'm able to consume messages from different addresses at once using single consumer (and still these behaves as queues - not topics).

Another question rised if I am able to pause address (using management API) - in docs I have found that I can pause queue (QueueImp.java) but I think that I can't do this for address. I'm right?

[clebert.suconic]

You never consume from an address, so there's no point on pausing a address.

Unless you meant stop all queues on an address? I don't think we have such operation.

[mateusz.gajewski]

Yes, you're right: I consume messages from queue bound to single or hierarchy of addresses. I can pause queue (so I will not consume from given address or hierarchy of addresses) but I can't pause consuming messages from subtree in adress hierarchy.

i.e.

queue "test" bound to address "test.#"

queue "testUser" bound to adress "test.user"

queue "testSomething" bound to address "test.something"

I want to consume messages from queue "test" (test.# address) but I also want to have ability to say "please don't consume messages on test.user for a while"

I think that pausing address consuming is a more general/abstract approach than pausing a queue