Re: [rules-users] Using KnowledgeAgent with Stateful session

Greetings: Nobody seems to be replying and I'm not really "qualified" to reply but I might be able to point you in the right direction. Long, long ago in a land far, far away we did a really cool project using Intelligent Agents and employed most of the technology from FIPA, The Foundation for Intelligent Physical Agents; see http://www.fipa.org/ for more information. SDG James Owen Founder October Rules Fest Senior Consultant / Architect KBSC http://www.kbsc.com http://www.OctoberRulesFest.org Twitter: OctRulesFest Blogs: http://JavaRules.blogspot.com [Rulebased Systems Blog] http://ORF2009.blogspot.com [October Rules Fest Blog] http://exscg.blogspot.com/ [Expert Systems Consulting Group Blog] "If I have seen a little further it is by standing on the shoulders of giants." Sir Isaac Newton in a letter to Robert Hooke, 5 Feb 1676 Come to October Rules Fest and stand on the shoulders of the Giants of the industry; if only for a week. On Aug 26, 2009, at 11:34 AM, 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/Using-KnowledgeAgent-with-Stateful-session-tp251514... > Sent from the drools - user mailing list archive at Nabble.com. > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users