[rules-dev] Drools Core Error?

[Nestor Tarin Burriel]

Hi Michael,

Attached a eclipse project with 2 sample apps showing my problem.

There are 2 main classes, 1 for CEP and STREAM enviroment and other without
them.

The extrange behavior is that the engine keeps the Working Memory correctly
and does the changes correctly in the nonTemporal enviroment
(ksession.insert()) but at the Temporal enviroment
(ksession.getWorkingMemoryEntryPoint("MyEntryPoint").insert(fact)) keeps the
WM and doesnt change the RuleBase.

Both main classes have 1 parameter setting the drl path:
file:src/main/resources/cepRule.drl
file:src/main/resources/nonCepRule.drl

Try execute both enviroments, do changes inside the DRLs and see if the
kagent updates the KSession correctly.

Thanks,

Nestor

PD: Actually I use both enviroments using the Guvnor PKG repository, in the
post I wrote the error thrown if I use Guvnor instead DRL files but is the
same problem as the attached project, the ksession doesnt refresh the
KnowledgeBase in my Temporal enviroment.

2009/9/1 Michael Neale <michael.neale at gmail.com>

> Hi Nestor - that is a tough one.
>
> I have a suspicion this is related to another issue I have seen with
> deserliasation of rulebases when the MVEL JIT kicks in... (from that
> strack trace it isn't getting the TypeDeclaration back...) - its a
> stretch, but might be related to:
> https://jira.jboss.org/jira/browse/JBRULES-2253
>
> As there are a few moving parts, if you could create a unit test that
> starts up a agent and shows this behaviour, that would be appreciated
> (confused about the interaction with entry points).
>
> Thanks,
>
> Michael.
>
>
>
> On Mon, Aug 31, 2009 at 8:38 PM, nestabur<nestabur at gmail.com> wrote:
> >
> > Any suggestions? I have my project in stand-by due to that problem ...
> >
> > Nestor
> >
> >
> > nestabur wrote:
> >>
> >> Does anyone tried to use the knowledgeAgent with statefulSessions?
> >>
> >> I've tried to configure my rule engine obtaining unexpected behaviour.
> >>
> >> I configure my statefulSession as follows:
> >>
> >> wm = (ReteooStatefulSession) ((KnowledgeBaseImpl) kagent
> >>
> >> .getKnowledgeBase()).ruleBase.newStatefulSession(
> >>                                 (SessionConfiguration) sessionConf,
> env);
> >> ksession = new StatefulKnowledgeSessionImpl(wm,
> >> kagent.getKnowledgeBase());
> >>
> >> And after updating the KnowledgeBase in the agent I update my ksession:
> >>
> >> wm.setRuleBase((InternalRuleBase) ((KnowledgeBaseImpl) kagent
> >>
> >> .getKnowledgeBase()).ruleBase);
> >> ksession = new StatefulKnowledgeSessionImpl(wm,
> >> kagent.getKnowledgeBase());
> >>
> >> Without using entry-points this approach works as expected, but using
> them
> >> it fails after the first update throwing the error:
> >>
> >> Exception while processing message: java.lang.NullPointerException
> >> java.lang.NullPointerException
> >>         at
> >>
> org.drools.reteoo.ReteooFactHandleFactory.newFactHandle(ReteooFactHandleFactory.java:54)
> >>         at
> >>
> org.drools.common.AbstractFactHandleFactory.newFactHandle(AbstractFactHandleFactory.java:79)
> >>         at
> >>
> org.drools.common.AbstractFactHandleFactory.newFactHandle(AbstractFactHandleFactory.java:66)
> >>         at
> >> org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:109)
> >>         at
> >> org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:80)
> >>         at
> >> org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:28)
> >>
> >> Browsing the drools core code I found the line that was throwing the
> >> exception and tried to get the same result by implementing:
> >>
> >> if (!((InternalRuleBase) ((KnowledgeBaseImpl)
> >> ksession.getKnowledgeBase()).ruleBase)
> >>                                 .getTypeDeclaration(fact.getClass()) ==
> >> null)
> >>         log.info (((InternalRuleBase) ((KnowledgeBaseImpl)
> >> ksession.getKnowledgeBase()).ruleBase)
> >>
> >>
> .getTypeDeclaration(fact.getClass()).getTimestampExtractor().toString());
> >>
> >> after updating my ksession. The result was the same, again the same
> >> exception thrown but my logger wrote:
> >> 18:01:50,232 INFO [ClassFieldExtractor class=MyPackage.MyFact
> >> field=myTimestampField]
> >>
> >> So I dont know why the core is throwing that exception, is that
> >> implementation correct?, any ideas?
> >>
> >>
> >> Thanks,
> >>
> >> Nestor
> >>
> >
> > --
> > View this message in context:
> http://www.nabble.com/Drools-Core-Error--tp25188219p25221364.html
> > Sent from the drools - dev mailing list archive at Nabble.com.
> >
> > _______________________________________________
> > rules-dev mailing list
> > rules-dev at lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/rules-dev
> >
>
>
>
> --
> Michael D Neale
> home: www.michaelneale.net
> blog: michaelneale.blogspot.com
>
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