5:06 a.m.
umberto maguolo [https://community.jboss.org/people/umb71] created the discussion
"timer job issues when disposing session in embedded j2ee process"
To view the discussion, visit: https://community.jboss.org/message/824721#824721
--------------------------------------------------------------
Hi all,
i'm using jBPM 5.4, I have a knowledge session with a process instance in it,
embebbed in an ejb with container managed transaction, the process definition has a timer
intermediate event in it:
i'm using jpa persistence but the problem arises also with in memory session without
persistence. I've utilized the CMTDisposeCommand class to register the synchronization
with the transaction manager and implemented the afterCompletion method to be notified
when the container finishes it's work committing the transaction; in the
afterCompletion method i've utilized the DefaultProcessEventListener and implemented
the afterProcessCompleted method so i can (at least i thought it was so) dispose my
knowledge session at the end of all the process elaboration.
The problem is that the process is regularly terminated but it seams that the timer
service sheduler is not aware of that fact neither that the session is disposed and it
continuosly try to signal the timer event on the session. When i call the
ksession.dispose, in the afterProcessCompleted method, i get the exception in the server
console:
SEVERE: Error when executing timer job
java.lang.IllegalStateException: Illegal method call. This session was previously
disposed.
at
org.drools.reteoo.DisposedReteooWorkingMemory.getLastIdleTimestamp(DisposedReteooWorkingMemory.java:562)
at
org.drools.impl.StatefulKnowledgeSessionImpl.getLastIdleTimestamp(StatefulKnowledgeSessionImpl.java:890)
at
org.drools.persistence.SingleSessionCommandService$EndOperationListenerImpl.endOperation(SingleSessionCommandService.java:334)
at
org.drools.common.AbstractWorkingMemory.endOperation(AbstractWorkingMemory.java:1365)
at
org.drools.common.AbstractWorkingMemory.executeQueuedActions(AbstractWorkingMemory.java:1006)
at
org.drools.impl.StatefulKnowledgeSessionImpl.executeQueuedActions(StatefulKnowledgeSessionImpl.java:866)
at
org.jbpm.process.instance.event.DefaultSignalManager.signalEvent(DefaultSignalManager.java:90)
at
org.jbpm.process.instance.timer.TimerManager$ProcessJob.execute(TimerManager.java:323)
at org.drools.time.SelfRemovalJob.execute(SelfRemovalJob.java:15)
at
org.drools.time.impl.DefaultTimerJobInstance.call(DefaultTimerJobInstance.java:51)
at
org.drools.persistence.jpa.JpaTimerJobInstance.internalCall(JpaTimerJobInstance.java:43)
at
org.drools.persistence.jpa.JDKCallableJobCommand.execute(JDKCallableJobCommand.java:20)
at
org.drools.persistence.jpa.JDKCallableJobCommand.execute(JDKCallableJobCommand.java:6)
at
org.drools.command.impl.DefaultCommandService.execute(DefaultCommandService.java:36)
at
org.drools.persistence.SingleSessionCommandService.execute(SingleSessionCommandService.java:373)
at
org.drools.persistence.jpa.JpaTimerJobInstance.call(JpaTimerJobInstance.java:34)
at
org.drools.persistence.jpa.JpaTimerJobInstance.call(JpaTimerJobInstance.java:14)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at
java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:178)
at
java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:292)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:722)
giu 25, 2013 11:46:41 AM org.drools.time.impl.DefaultTimerJobInstance call
WARNING: Unable to execute timer job!
java.lang.IllegalStateException: Illegal method call. This session was previously
disposed.
at
org.drools.reteoo.DisposedReteooWorkingMemory.getProcessInstance(DisposedReteooWorkingMemory.java:382)
at
org.drools.impl.StatefulKnowledgeSessionImpl.getProcessInstance(StatefulKnowledgeSessionImpl.java:297)
at
org.jbpm.process.instance.timer.TimerManager$ProcessJob.execute(TimerManager.java:335)
at org.drools.time.SelfRemovalJob.execute(SelfRemovalJob.java:15)
at
org.drools.time.impl.DefaultTimerJobInstance.call(DefaultTimerJobInstance.java:51)
at
org.drools.persistence.jpa.JpaTimerJobInstance.internalCall(JpaTimerJobInstance.java:43)
at
org.drools.persistence.jpa.JDKCallableJobCommand.execute(JDKCallableJobCommand.java:20)
at
org.drools.persistence.jpa.JDKCallableJobCommand.execute(JDKCallableJobCommand.java:6)
at
org.drools.command.impl.DefaultCommandService.execute(DefaultCommandService.java:36)
at
org.drools.persistence.SingleSessionCommandService.execute(SingleSessionCommandService.java:373)
at
org.drools.persistence.jpa.JpaTimerJobInstance.call(JpaTimerJobInstance.java:34)
at
org.drools.persistence.jpa.JpaTimerJobInstance.call(JpaTimerJobInstance.java:14)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at
java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:178)
at
java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:292)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:722)
I've also tried to cancel any TimerJobInstance in the TimerService prior to dispose
the session but the problem is still present. Am i doing something wrong? Missing
something? What is the correct way of disposing session with (terminated) timer events in
it?
Thanks.
Umberto
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6:10 a.m.
New subject: [jBPM] - Re: timer job issues when disposing session in embedded j2ee process
Jiri Svitak [https://community.jboss.org/people/jsvitak] created the discussion
"Re: timer job issues when disposing session in embedded j2ee process"
To view the discussion, visit: https://community.jboss.org/message/824730#824730
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Hi Umberto,
jBPM engine uses knowledge sessions for running process instances. Listeners are
registered in the sessions. So your processes instance has not ended yet and you are
trying to dispose its underlying session, which also contains your listener. That
won't work.
So to solve the problem, I think that you should not try to dispose the session inside
listener method. You should implement another (waiting) mechanism, which will dispose the
session only when it is safe - when all process instances of the session are not running.
There are many patterns how to use sessions. For example:
- waiting mechanism, for example you can use waiting after startProcess() method,
decrement CountDownLatch in the listener and after that dispose the session
- or you should not dispose the session when using timers (singleton session pattern) -
because if you dispose session directly after startProcess(), the timer will not fire,
because its session is not active
- ...
My two cents.
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7:27 a.m.
New subject: [jBPM] - Re: timer job issues when disposing session in embedded j2ee process
umberto maguolo [https://community.jboss.org/people/umb71] created the discussion
"Re: timer job issues when disposing session in embedded j2ee process"
To view the discussion, visit: https://community.jboss.org/message/824748#824748
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Hi Jiri,
thanks for your response. Indeed i've followed the indication of Maciej Swiderski in
this post http://mswiderski.blogspot.it/2012/10/dispose-session-in-cmt-environment....
http://mswiderski.blogspot.it/2012/10/dispose-session-in-cmt-environment.... when it is
clearly explained that in case such mine, CMT j2ee object embedded processes, the correct
pattern to use to dispose a session seems to be the one that utilized the
ProcessEventListeners. And without timers in the process definition it works like a charm.
When i'm in the afterProcessCompleted method I'm sure the process is terminated,
i've
checked with appropriate code: no process instance active, nor timer node instances.
I repeat my guess: it seems that the timer service sheduler is not aware of the fact that
the session is disposed and it continuosly try to signal the timer event on the session
itself.
Regards.
Umberto
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10:17 a.m.
New subject: [jBPM] - Re: timer job issues when disposing session in embedded j2ee process
Jiri Svitak [https://community.jboss.org/people/jsvitak] created the discussion
"Re: timer job issues when disposing session in embedded j2ee process"
To view the discussion, visit: https://community.jboss.org/message/824808#824808
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Hi Umberto,
Thanks for the link to Maciej's blog. It is helpful. Maybe I am missing something, but
Maciej uses there own defined
http://people.redhat.com/mswiders/blogs/cmt-dispose/CMTDisposeCommand.java
CMTDisposeCommand, not ProcessEventListener. The same applies for method name - he uses
afterCompletion() to dispose, not afterProcessCompleted(). Is it possible that this is the
problem?
Also keep in mind, that timers are special case and there are scenarios, where you cannot
use session per process instance pattern - as I said timer cannot trigger in disposed
session.
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11:49 a.m.
New subject: [jBPM] - Re: timer job issues when disposing session in embedded j2ee process
umberto maguolo [https://community.jboss.org/people/umb71] created the discussion
"Re: timer job issues when disposing session in embedded j2ee process"
To view the discussion, visit: https://community.jboss.org/message/824826#824826
--------------------------------------------------------------
Hi Jiri,
you're right, i ain't been so clear: i've modified the Maciej's
CMTDisposeCommand class, in the afterCompletion method i've introduced the
registration on the ProcessEventListener interface and implemented the
afterProcessCompleted method, as a mechanism to wait for process completion. As i said,
the timer in the process and the process itself are terminated when i enter in the
afterProcessCompleted method, so i don't think that's the problem. But you have
given me a correct suggestion when you said that the events listeners are part of the
session, so it's probably not correct dispose the session when i'm in the
afterProcessCompleted. I will try to wait for process completion directly in the
afterCompletion method, using another strategy, and let you know the results.
In the mean time i thank you very much your help.
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5:22 a.m.
New subject: [jBPM] - Re: timer job issues when disposing session in embedded j2ee process
umberto maguolo [https://community.jboss.org/people/umb71] created the discussion
"Re: timer job issues when disposing session in embedded j2ee process"
To view the discussion, visit: https://community.jboss.org/message/824964#824964
--------------------------------------------------------------
Hi,
ok, i've found a solution. In my EJB project, in the method exposed, i create a
knowledge session per call, and a single process instance:
1. create the process instance:
logger.debug(">>> create a process instance");
ProcessInstance procInstance =
ksession.createProcessInstance("test.TestComplete", params);
2. register transaction manager synchronization using Maciej's original
CMTDisposeCommand (in the afterCompletion method i dispose the ksession):
<code>
logger.debug(">>> register transaction synchronization");
ksession.execute(new CMTDisposeCommand());
</code>
3. create and register a new class, CMTProcessEventListener, to listen for the process
complete event (code attached below)
<code>
CMTProcessEventListener procEventListener = new
CMTProcessEventListener(procInstance.getId(),ejbName);
logger.debug(">>> add process events listener");
ksession.addEventListener(procEventListener);
</code>
4. start the process instance execution:
<code>
logger.debug(">>> start the process instance");
ksession.startProcess(procInstance.getProcessId());
</code>
5. at this point, i've implemented a cycle in my code to wait until the
procEventListener.isProcessCompleted() is true before terminate the ejb method.
The jBPM engine notify the CMTProcessEventListener after the process complete, timer
included, the EJB method ends so the ejb container commits the transaction and call the
afterCompletion method so i can dispose che session.
Thank you very much Jiri, hope this help someone else too.
Umberto
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umberto maguolo