I'm afraid this bug is not resolved and doesn't have nothing to do with lazy evaluation.<br><br>We've been able to get to the source of the problem and this are the facts:<br><br> - Drools and JBPM have different persistence managers.<br>
- Drools uses JTA for persistence and JBPM does not.<br> - When any JPA enabled object is persisted in Drools, a transaction begins, it's EntityManager ( Hibernate ) joins the transaction and the entity gets persisted. <br>
- When any JPA enabled object ( in this case a ProcessInstanceInfo ) is persisted in JBPM, there are no transactions involved, and so the EntityManager ( Hibernate ) decides to delay the insert ( queuing it as there's no transaction in progress ). Then the processId never gets updated and the NPE arises.<br>
<br>The problem here seems to be that both Drools and JBPM manage persistence in different and incompatible ways. We've been able to modify jbpm-persistence-jpa to open a JTA transaction before persisting ProcessInstanceInfo, getting the EntityManager joining that transaction and using the current Bitronix implementation already running in Drools ( to assist persistence for their objects ) .. like so:<br>
<br> public void setKnowledgeRuntime(InternalKnowledgeRuntime kruntime) {<br> this.kruntime = kruntime;<br> Environment env = kruntime.getEnvironment();<br> Object tm = env.get( EnvironmentName.TRANSACTION_MANAGER );<br>
if (!(tm instanceof javax.transaction.TransactionManager)) {<br> try {<br> // get Bitronix instance inside ...<br> java.lang.reflect.Field field = tm.getClass().getDeclaredField("tm");<br>
// who says private in Java is really private ... xD<br> field.setAccessible(true);<br> tm = field.get(tm);<br> } catch (Exception e){<br> e.printStackTrace();<br>
}<br> }<br> this.txm = new JtaTransactionManager( env.get( EnvironmentName.TRANSACTION ), env.get( EnvironmentName.TRANSACTION_SYNCHRONIZATION_REGISTRY ), tm );<br> }<br><br> public void addProcessInstance(ProcessInstance processInstance) {<br>
ProcessInstanceInfo processInstanceInfo = new ProcessInstanceInfo( processInstance, this.kruntime.getEnvironment() );<br> ProcessPersistenceContext context = ((ProcessPersistenceContextManager) this.kruntime.getEnvironment().get( EnvironmentName.PERSISTENCE_CONTEXT_MANAGER )).getProcessPersistenceContext();<br>
this.txm.begin();<br> context.persist( processInstanceInfo );<br> this.txm.commit();<br><br><br><br>I think we can agree that the previous lines of code are not the most elegant solution ( at least not for me ).<br>
<br>So, Is there any timeline for merging DROOLS and JBPM 5 persistence managers? <br><br>If someone gives me advice and architectural hints ( and if it is doable in a reasonable ammount of time ) I would be eager to submit a patch for this ....<br>
<br><br clear="all">Alberto R. Galdo<br><a href="mailto:argaldo@gmail.com">argaldo@gmail.com</a><br><br><br><div class="gmail_quote">On Wed, Mar 14, 2012 at 13:56, Alberto R. Galdo <span dir="ltr"><<a href="mailto:argaldo@gmail.com">argaldo@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Great news!<br><br>We were in the process of debugging JBPM trying to find the source of the bug ... and maybe days away from the solution ...<br>
<br>Is
there any bug report in Jira and/or a patch we can apply without having
to wait for the next release so we can quick-patch our systems?<span class="HOEnZb"><font color="#888888"><br><br><br clear="all">Alberto R. Galdo<br><a href="mailto:argaldo@gmail.com" target="_blank">argaldo@gmail.com</a></font></span><div class="HOEnZb">
<div class="h5"><br><br><br><div class="gmail_quote">On Wed, Mar 14, 2012 at 13:09, Marco Rietveld <span dir="ltr"><<a href="mailto:mrietvel@redhat.com" target="_blank">mrietvel@redhat.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<br>
Hi Alberto, <br>
<br>
This is a bug that has been fixed in jBPM. It had to do with lazy
initialization of a <font face="Default Sans
Serif,Verdana,Arial,Helvetica,sans-serif">JPAProcessInstanceManager</font>
field. <br>
<br>
We'll be releasing a new jBPM version sometime soon (synchronous
with Drools, I think). The bug is fixed in there. <br>
<br>
Regards,<br>
Marco<br>
<br>
03/08/2012 11:32 AM, Alberto R. Galdo:
<blockquote type="cite"><div><div><font face="Default Sans
Serif,Verdana,Arial,Helvetica,sans-serif">
<div>Hi, </div>
<div><br>
</div>
<div> We're running an application that uses Drools + JBPM 5 +
Drools integration our set-up can be seen as: </div>
<div>
<br>
</div>
<div> Some rule fires and creates a JBPM process ( a fact gets
inserted into drools using
"kcontext.getKnowledgeRuntime().startProcess("testProcess")"
). We have a problem with the persistence of this processes.
Persistence is implemented with JPA and JTA. Our application
runs with fireUntilHalt() and when a process is launched from
the consequence of any of the rules the persistence of the
process fails. If the application runs with fireAllRules(),
the persistence works like a charm.</div>
<div> </div>
<div> The error shown is as follow:</div>
<div> </div>
<div> Exception in thread "Thread-5" Exception executing
consequence for rule "Run Process" in com.sample:
java.lang.NullPointerException</div>
<div><span style="white-space:pre-wrap"> </span>at
org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)</div>
<div><span style="white-space:pre-wrap"> </span>at
org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1101)</div>
<div><span style="white-space:pre-wrap"> </span>at
org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:1029)</div>
<div><span style="white-space:pre-wrap"> </span>at
org.drools.common.DefaultAgenda.fireUntilHalt(DefaultAgenda.java:1229)</div>
<div><span style="white-space:pre-wrap"> </span>at
org.drools.common.AbstractWorkingMemory.fireUntilHalt(AbstractWorkingMemory.java:754)</div>
<div><span style="white-space:pre-wrap"> </span>at
org.drools.common.AbstractWorkingMemory.fireUntilHalt(AbstractWorkingMemory.java:730)</div>
<div><span style="white-space:pre-wrap"> </span>at
org.drools.command.runtime.rule.FireUntilHaltCommand$1.run(FireUntilHaltCommand.java:50)</div>
<div><span style="white-space:pre-wrap"> </span>at
java.lang.Thread.run(Thread.java:662)</div>
<div>Caused by: java.lang.NullPointerException</div>
<div><span style="white-space:pre-wrap"> </span>at
org.jbpm.persistence.processinstance.JPAProcessInstanceManager.addProcessInstance(JPAProcessInstanceManager.java:44)</div>
<div><span style="white-space:pre-wrap"> </span>at
org.jbpm.process.instance.AbstractProcessInstanceFactory.createProcessInstance(AbstractProcessInstanceFactory.java:36)</div>
<div><span style="white-space:pre-wrap"> </span>at
org.jbpm.process.instance.ProcessRuntimeImpl.startProcess(ProcessRuntimeImpl.java:182)</div>
<div><span style="white-space:pre-wrap"> </span>at
org.jbpm.process.instance.ProcessRuntimeImpl.createProcessInstance(ProcessRuntimeImpl.java:154)</div>
<div><span style="white-space:pre-wrap"> </span>at
org.jbpm.process.instance.ProcessRuntimeImpl.startProcess(ProcessRuntimeImpl.java:135)</div>
<div><span style="white-space:pre-wrap"> </span>at
org.jbpm.process.instance.ProcessRuntimeImpl.startProcess(ProcessRuntimeImpl.java:130)</div>
<div><span style="white-space:pre-wrap"> </span>at
org.drools.common.AbstractWorkingMemory.startProcess(AbstractWorkingMemory.java:1074)</div>
<div><span style="white-space:pre-wrap"> </span>at
org.drools.impl.StatefulKnowledgeSessionImpl.startProcess(StatefulKnowledgeSessionImpl.java:301)</div>
<div><span style="white-space:pre-wrap"> </span>at
com.sample.Rule_Run_Process.defaultConsequence(Rule_Run_Process.java:9)</div>
<div><span style="white-space:pre-wrap"> </span>at
com.sample.Rule_Run_ProcessDefaultConsequenceInvoker.evaluate(Unknown
Source)</div>
<div><span style="white-space:pre-wrap"> </span>at
org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1091)</div>
<div><span style="white-space:pre-wrap"> </span>... 6 more</div>
<div><span style="white-space:pre-wrap"> </span></div>
<div><span style="white-space:pre-wrap"> </span>The problem is
in this function:</div>
<div><span style="white-space:pre-wrap"> </span></div>
<div><span style="white-space:pre-wrap"> </span>public void
addProcessInstance(ProcessInstance processInstance) {</div>
<div> ProcessInstanceInfo processInstanceInfo = new
ProcessInstanceInfo( processInstance,
this.kruntime.getEnvironment() );</div>
<div> ProcessPersistenceContext context </div>
<div> = ((ProcessPersistenceContextManager)
this.kruntime.getEnvironment()</div>
<div> .get(
EnvironmentName.PERSISTENCE_CONTEXT_MANAGER ))</div>
<div> .getProcessPersistenceContext();</div>
<div> // @PrePersist added to ProcessInstanceInfo because
of this</div>
<div> context.persist( processInstanceInfo );</div>
<div> ((org.jbpm.process.instance.ProcessInstance)
processInstance).setId( processInstanceInfo.getId() );</div>
<div> processInstanceInfo.updateLastReadDate();</div>
<div> internalAddProcessInstance(processInstance);</div>
<div> }</div>
<div><span style="white-space:pre-wrap"> </span></div>
<div><span style="white-space:pre-wrap"> </span>We think after
that persist sentence, the entity manager would have to run a
flush sentence for the process instance is inserted into
database and get the ID.</div>
<div><span style="white-space:pre-wrap"> </span></div>
<div><span style="white-space:pre-wrap"> </span>Greets.</div>
</font>
<br>
<fieldset></fieldset>
<br>
</div></div><div><pre>_______________________________________________
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</div></blockquote><span><font color="#888888">
<br>
<br>
<pre cols="72">--
jBPM/Drools developer
Utrecht, the Netherlands</pre>
</font></span></div>
</blockquote></div><br>
</div></div></blockquote></div><br>