Distributed JMS Topic consumer reconnection... How???

Question

Hi!
          I'm trying to develop a JMS consumer that is connected to a distributed topic located in a 2-machine cluster. The client knows the address of the two servers, so the idea is to catch the JMSException (JMS destination shutdown) with a ExceptionListener (or something like that) if one server fails, and then try to connect to the other one...
          I've been browsing Weblogic docs but I didn't find any example for this.
          How do I implement my consumer? Is there any other approach to my problem?
          Thanks a lot!
          Jorge Granado
          

Answer 1

          Hi Tom:
          Finally I've been able to reconnect my consumer. I took a "clean" one (mine was
          getting too complicated :-) and it worked. I took the TopicReceive sample from
          bea samples and added a "reconnect" method following your recommendations about
          reusing existing ConnectionFactory. I'm beginning to think I was forgetting to
          start the connection, but anyway now it works great. Thanks a lot!
          BTW, could you explain to me how can I change (if possible) in "real-time" the
          MessageSelector properies for an existing consumer? Suppose that I have a consumer
          connected to a topic with a selector like "priority >=2" and I'd like to change
          it to "priority >=3" without restarting the application... Is it possible??
          Thanks again
          Jorge
          Tom Barnes <[email protected].bea.com>
          wrote:
          >Seems like your following the recipe correctly. :-)
          >
          >Could you try this on a platform other than AIX?
          >
          >Are you using the same version of WL jars for client and server?
          >
          >Are you using the new 8.1 "thin client" jars for the client? If
          >so try using weblogic.jar instead (don't put both kinds
          >of jars in your classpath).
          >
          >
          >"Jorge Granado" jorge.granadoATatosorigin.com wrote:
          >
          >> Hi again!
          >>
          >> Well, maybe there's something I don't get, but what I'm trying to do
          >is:
          >>
          >> -Create a topic consumer and connect it to the distributed topic (standard
          >process...)
          >> -Shutdown the server where the consumer is connected...
          >> -Capture the exception
          >> -Close the topic connection
          >> -Create a new one reusing existing topic connection factory (as you
          >told me there's
          >> no need to make a lookup again...)
          >> -Create a topic session over the new topic connection
          >> -Create a subscriber
          >> -Read messages... :-)
          >>
          >> But in 5th step what I get is a new Exception... "Error creating connection
          >to
          >> the server"
          >>
          >> I'm sure I've misunderstood something... :-(
          >>
          >> Thanks again for your patience :-)
          >>
          >> Jorge
          >>
          >> Tom Barnes <[email protected].bea.com>
          >> wrote:
          >>
          >>>No, I don't know what is happening. I wonder if you are
          >>>somehow multi-threading the session? Try closing
          >>>the old connection before reconnecting. And note that
          >>>there is no need to lookup up the CF again, as the old CF
          >>>should work fine (it is a clusterable RMI reference,
          >>>so it can survive failures).
          >>>
          >>>"Jorge Granado" jorge.granadoATatosorigin.com wrote:
          >>>
          >>>>Now I've created a consumer, and when catching the session exception
          >>>
          >>>and try to
          >>>
          >>>>reconnect to another WL instance, when I make the JNDI lookup to my
          >>>
          >>>connection
          >>>
          >>>>factory, instead of getting a weblogic.jms.client.JMSConnectionFactory
          >>>
          >>>what I
          >>>
          >>>>get is an weblogic.jms.frontend.FEConnectionFactory_812_WLStub_812_WLStub.
          >>>
          >>>>This causes a ClassCastException and I can't connect to it. Any idea
          >>>
          >>>what is happening?
          >>>
          >>>>Thanx again :-)
          >>>>
          >>>> Jorge
          >>>>
          >>>>BTW, I'm using WL 8.1 SP2 (AIX platform)
          >>>>
          >>>>Tom Barnes <[email protected].bea.com>
          >>>>wrote:
          >>>>
          >>>>
          >>>>>Hi Jorge,
          >>>>>
          >>>>>Registering exception-listeners and retrying on failure
          >>>>>seems like the right approach. I'm not sure what you
          >>>>>are looking for in an example.
          >>>>>
          >>>>>For more information on JMS clustering, I recommend reading
          >>>>>the JMS Performance Guide white-paper on dev2dev:
          >>>>>
          >>>>>http://dev2dev.bea.com/technologies/jms/index.jsp
          >>>>>
          >>>>>Tom, BEA
          >>>>>
          >>>>>P.S. One thing to realize is that WebLogic distinguishes between
          >>>>>"session" exceptions and "ccnnection" exceptions. Shutting
          >>>>>down JMS without shutting down a client connection's WL
          >>>>>server only generates session exceptions, as the connection
          >>>>>is still valid. To monitor session exceptions, register
          >>>>>a session exception listener (see the weblogic.jms.extensions
          >>>>>package).
          >>>>>
          >>>>>Jorge Granado wrote:
          >>>>>
          >>>>>
          >>>>>
          >>>>>>Hi!
          >>>>>>
          >>>>>>I'm trying to develop a JMS consumer that is connected to a distributed
          >>>>>
          >>>>>topic located in a 2-machine cluster.
          >>>>>
          >>>>>
          >>>>>>The client knows the address of the two servers, so the idea is
          >to
          >>>>>
          >>>>>catch the JMSException (JMS destination shutdown)
          >>>>>
          >>>>>with a ExceptionListener (or something like that) if one server fails,
          >>>>>
          >>>>>and then try to connect to the other one...
          >>>>>
          >>>>>
          >>>>>>I've been browsing Weblogic docs but I didn't find any example for
          >>>>>
          >>>>>this.
          >>>>>
          >>>>>
          >>>>>>How do I implement my consumer? Is there any other approach to my
          >>>
          >>>problem?
          >>>
          >>>>>>Thanks a lot!
          >>>>>>
          >>>>>> Jorge Granado
          >>>>>
          >>
          >