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https://issues.apache.org/jira/browse/AMQ-4797?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13792891#comment-13792891
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Bill Harts commented on AMQ-4797:
---------------------------------
Thanks, Tim. I just tried the latest
apache-activemq-5.9-20131010.203434-114-bin snapshot and it still exhibits the
same behavior.
FYI, I have downloaded all the sources and removed what I thought was the
offending line 165 in MessageListenerServlet.js but it still fails. So much
for my first foray into the guts of ActiveMQ.
Bill
> Unable to add multiple AJAX listeners for the same topic in the same browser
> window
> -----------------------------------------------------------------------------------
>
> Key: AMQ-4797
> URL: https://issues.apache.org/jira/browse/AMQ-4797
> Project: ActiveMQ
> Issue Type: Bug
> Affects Versions: 5.8.0
> Environment: Windows Server 2008 R2 on Dell server boxes
> Reporter: Bill Harts
> Labels: addlistener, ajax, web
>
> I'm using ExtJS to create two separate panels which run in one browser tab.
> After loading jquery, amq_jquery_adapter.js and amq.js I call amq_init (only
> once). Then each panel calls addlistener like so:
> Panel 1 code:
> {code}amq.addListener('testconnection1', topic://MyApp/IOIs/Simulator',
> myHandler1.rcvMessage);{code}
> Panel 2 code:
> {code}amq.addListener('testconnection2', 'topic://MyApp/IOIs/Simulator',
> myHandler2.rcvMessage);{code}
> Note that both are subscribing to the same topic. This is because Panel 1
> shows the data in a different format than Panel 2.
> *The Problem:*
> If I start Panel 1 alone, it receives data from the topic without problems.
> But then I start Panel 2 and as soon as it executes the addlistener, Panel 2
> starts receiving data but Panel 1 stops!
> So I started tracing into the network traffic and all looks fine, i.e, I can
> see each addlistener trigger a 'listen' request with the proper id and topic.
> And I see the amq server return data to testconnection1, then stop suddenly
> when the 'listen' for testconnection2 is sent. So I turned my attention to
> the backend code and enabled a detailed trace. Here's what I found:
> When the Panel 1 'listen' is received, the trace shows:
> {quote}2013-10-10 09:10:09,701 | DEBUG | 0
> destination=topic://MyApp/IOIs/Simulator message=testconnection1 type=listen
> | org.apache.activemq.web.MessageListenerServlet | qtp2088898587-51 -
> /demo/amq
> 2013-10-10 09:10:09,701 | DEBUG | topic://MyApp/IOIs/Simulator is a
> org.apache.activemq.command.ActiveMQTopic |
> org.apache.activemq.web.MessageListenerServlet | qtp2088898587-51 - /demo/amq
> 2013-10-10 09:10:09,701 | DEBUG | amq-broker adding consumer:
> ID:MYAPPDATA-7392-1381410590247-5:1:1:1 for destination:
> topic://MyApp/IOIs/Simulator |
> org.apache.activemq.broker.region.AbstractRegion | ActiveMQ VMTransport:
> vm://localhost#1-2
> 2013-10-10 09:10:09,701 | DEBUG | amq-broker adding destination:
> topic://ActiveMQ.Advisory.Consumer.Topic.MyApp/IOIs/Simulator |
> org.apache.activemq.broker.region.AbstractRegion | ActiveMQ VMTransport:
> vm://localhost#1-2
> 2013-10-10 09:10:09,717 | DEBUG | Initialized TaskRunnerFactory[ActiveMQ
> Session Task] using ExecutorService:
> java.util.concurrent.ThreadPoolExecutor@2e2667db[Running, pool size = 0,
> active threads = 0, queued tasks = 0, completed tasks = 0] |
> org.apache.activemq.thread.TaskRunnerFactory | qtp2088898587-51 - /demo/amq
> 2013-10-10 09:10:09,717 | DEBUG | Subscribed: ActiveMQMessageConsumer {
> value=ID:MYAPPDATA-7392-1381410590247-5:1:1:1, started=true } to
> topic://MyApp/IOIs/Simulator id=testconnection1 |
> org.apache.activemq.web.MessageListenerServlet | qtp2088898587-51 -
> /demo/amq{quote}
> When the Panel 2 'listen' is received, I see this trace:
> {quote}2013-10-10 09:10:09,888 | DEBUG | 0
> destination=topic://MyApp/IOIs/Simulator message=testconnection2 type=listen
> | org.apache.activemq.web.MessageListenerServlet | qtp2088898587-53 -
> /demo/amq
> 2013-10-10 09:10:09,888 | DEBUG | topic://MyApp/IOIs/Simulator is a
> org.apache.activemq.command.ActiveMQTopic |
> org.apache.activemq.web.MessageListenerServlet | qtp2088898587-53 - /demo/amq
> 2013-10-10 09:10:09,888 | DEBUG | remove:
> ID:MYAPPDATA-7392-1381410590247-5:1:1:1, lastDeliveredSequenceId:0 |
> org.apache.activemq.ActiveMQMessageConsumer | qtp2088898587-53 - /demo/amq
> 2013-10-10 09:10:09,888 | DEBUG | Unregistering MBean
> org.apache.activemq:type=Broker,brokerName=amq-broker,destinationType=Topic,destinationName=MyApp/IOIs/Simulator,endpoint=Consumer,clientId=ID_MYAPPDATA-7392-1381410590247-4_1,consumerId=ID_MYAPPDATA-7392-1381410590247-5_1_1_1
> | org.apache.activemq.broker.jmx.ManagementContext | ActiveMQ VMTransport:
> vm://localhost#1-2
> 2013-10-10 09:10:09,888 | DEBUG | amq-broker removing consumer:
> ID:MYAPPDATA-7392-1381410590247-5:1:1:1 for destination:
> topic://MyApp/IOIs/Simulator |
> org.apache.activemq.broker.region.AbstractRegion | ActiveMQ VMTransport:
> vm://localhost#1-2
> 2013-10-10 09:10:09,888 | DEBUG | amq-broker adding consumer:
> ID:MYAPPDATA-7392-1381410590247-5:1:1:2 for destination:
> topic://MyApp/IOIs/Simulator |
> org.apache.activemq.broker.region.AbstractRegion | ActiveMQ VMTransport:
> vm://localhost#1-2
> 2013-10-10 09:10:09,904 | DEBUG | Subscribed: ActiveMQMessageConsumer {
> value=ID:MYAPPDATA-7392-1381410590247-5:1:1:2, started=true } to
> topic://MyApp/IOIs/Simulator id=testconnection2 |
> org.apache.activemq.web.MessageListenerServlet | qtp2088898587-53 -
> /demo/amq{quote}
> What is happening is that in MessageListenerServlet.js, function doPost, line
> 165 is dropping any previous consumer to the same destination:
> {code}client.closeConsumer(destination); // drop any existing consumer.{code}
> But why? There doesn't seem to be a good reason for doing this--maybe it was
> originally put there for cleanup purposes?. Or if there is a good reason,
> maybe the behavior should be to not do it if the id of the new destination
> (in this case 'testconnection2') is different than the id of the existing
> destination ('testconnection1').
> I believe this can be fixed by simply removing line 165 from
> MessageListenerServlet.js but I'm not sure if this will break something else.
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