Re: [rules-users] Some Problem with drools-persistence-jpa Library
Hi,
If you use persistence, you should use ksession.signalEvent(type, event,
processInstanceId) instead of signaling the process instance itself.
The reason is that, if you're using persistence, the state of the
process instance is stored in the database after processing and the
process instance is disconnected (that is why the working memory is
null). The process instance object that you are receiving is just a
value object (and can for example be sent to a remote machine like the
client side). If you use the signalEvent method on the session, the
process instance will be reloaded and reconnect again, so I think that
should solve your issue.
Kris
tangrui.cn(a)gmail.com wrote:
And another tip is that after ksession.startProcess, I get a
ProcessInstance pi, but
ProcessInstance pi = ksession.startProcess("com.zyeeda.system.TestFlow");
org.drools.process.instance.ProcessInstance pi2 =
(org.drools.process.instance.ProcessInstance) pi;
pi2.getWorkingMemory() // this one returns null
Is this a bug or my usage problem?
On Sun, Nov 7, 2010 at 5:51 PM, tangrui.cn
<http://tangrui.cn>@gmail.com <http://gmail.com> <tangrui.cn
<http://tangrui.cn>@gmail.com <http://gmail.com>> wrote:
Hi list,
The attachment is a very simple test case to demonstrate an
application using Drools Persistence JPA (5.1.1).
Usage:
1. set up a mysql database called framework
2. set the user/password are root/root (or change the
bitronix-datasources.properties file)
3. run maven test
The core lines are as following:
StatefulKnowledgeSession ksession =
JPAKnowledgeService.newStatefulKnowledgeSession(kbase, conf, env);
ProcessInstance pi =
ksession.startProcess("com.zyeeda.system.TestFlow");
pi.signalEvent("signal", "goon");
When executing the 3rd line, an exception occurred
java.lang.NullPointerException
at
org.drools.process.instance.impl.ProcessInstanceImpl.getProcess(ProcessInstanceImpl.java:67)
at
org.drools.workflow.instance.impl.WorkflowProcessInstanceImpl.getWorkflowProcess(WorkflowProcessInstanceImpl.java:185)
at
org.drools.workflow.instance.impl.WorkflowProcessInstanceImpl.signalEvent(WorkflowProcessInstanceImpl.java:346)
at com.zyeeda.test.AppTest.testProcessPersistence(AppTest.java:84)
I've headed into the code and find that some working memory
related to the ProcessInstanceImpl is null.
(drools-core/src/main/java/org/drools/process/instance/impl/ProcessInstanceImpl.java)
But I cannot get why this does happen. Please give me some tips.
I tried to google some solutions, but find only this one
(http://drools-java-rules-engine.46999.n3.nabble.com/Drools-Flow-Events-No...),
but it seems that he solved this problem by using a custom command.
Thank you!
--
唐睿
--
唐睿
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