While this is possible, it's not desirable because of the dynamic nature of my pub/sub. I was planning to use the VirtualTopic [queue-backed] approach for the dynamic event subscribing side of things because of the performance it claims and the fact that each consumer/destination pair is run on it's own thread from ActiveMQ's threadpool.
So, for example, if I have P1 and P2 as the event publishers and C1 as the subscriber [to both publisher's events], I would have the following destinations: P1 = VirtualTopic.P1 P2 = VirtualTopic.P2 C1 = Consumer.C1.VirtualTopic.P1 C1 = Consumer.C1.VirtualTopic.P2 As you can see from the VirtualTopic approach - the number of destinations is really dynamic. As C1 subscribes/unsubscribes to P# publishers - the consumer/destination(s) will change. I want to avoid having to do thread management for all of this - since it appears that ActiveMQ should fit the bill. I'm working on the implementation now where I keep a ConcurrentHashMap<String, MessageConsumer> collection. When a new subscription is added, I just create the consumer on the fly and wire it to my existing OnMessage handler. I'll see how this works. It VirtualTopics aren't designed for scenarios where there will be lots of subscribers and the list changes dynamically at runtime - please let me know. Thanks, Bob Joe Fernandez wrote: > > Can you have two instances of the same POJO? If so, create two separate > threads with their own sessions to the appropriate destination and give > each thread an instance of the POJO. > > What about spawning multiple threads, each having their own Session, > instance of the message listener POJO, and pointed to a particular > destination? > > Joe > http://www.ttmsolutions.com > > > bob.deremer wrote: >> >> Hi ActiveMQ experts, >> >> I have a scenario where I'd like to create a single MessageListener POJO, >> but it needs to be a listener on multiple queues. The reason is that I'm >> trying to support the following 2 cases: >> >> 1) a pub/sub event model using Virtual Topics. As a result, each >> subscriber (i.e. MessageListener) must be a separate Queue following the >> VirtualTopic naming convention. This means that there could be 0 - many >> queues this single POJO may be receiving messages from - based on what >> events the POJO is subscribed. In addition, these subscriber queues will >> be added/removed dynamically >> 2) a request/reply model with the same POJO. This one is easy, as I'll >> create a single Queue/POJO to handle incoming request messages. >> >> So, is this possible? And - even if it's possible, [IS IT A GOOD IDEA?] >> While something may be possible, it might not be a design. I cannot >> create a single POJO per destination and to support both request/response >> + event subscription - i will still need a minimum of 1 Topic + 1 Queue = >> 2 destinations going to the same POJO. >> >> Thanks in advance for any suggestions and please let me know if you need >> any further details, >> Bob DeRemer >> > > -- View this message in context: http://old.nabble.com/Is-it-possible-to-have-1-MessageListener-POJO-handle-multiple-queues--tp27452190p27456648.html Sent from the ActiveMQ - User mailing list archive at Nabble.com.
