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
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