Re: [rules-users] Manuel's Analysis of JBRULES-2887 (NPE in AccumulateNode.java:967)

Thanks a lot, and I've added your analysis as a comment to JBRULES-2887. Wolfgang 2011/4/3 Manuel Ortiz <manuel.ortizramos(a)gmail.com&gt; > Hi Wolfgang: > > I write to you concerning JIRA > https://issues.jboss.org/browse/JBRULES-2887, which the SampleAlarmRules > scenario which was attached to this discussion was added in. > > I've executed several times the SampleAlarmRules scenario and found that > the problem in that scenario is the existence of a JoinNode (Node 18) which > feeds two nodes, a JoinNode (Node 20) and an AccumlateNode (Node 25, the one > in which NPE occurs). I've seen that the child tuples of a join node are > interconnected via pointers and that those connections must be updated every > time a parent tuple of the join node is modified, via reAddLeft and > reAddRight tuple methods. When a JoinNode feeds two or more nodes, the child > tuples are interconnected in a ordered way that mixes tuples with different > sinks. > > In the SampleAlarmRules scenario, when JoinNode18 is right modified, the > CompositeLeftTupleSinkAdapter processes several child tuples, but only the > last one is returned and reAddLeft'ed, hence breaking the child tuple > relations which it seems necessary to keep rete coherence. After this right > modify, the next left modify fails because a child tuple related to one node > of the composite sink is used to check the next operation to do in another > sink node different from the first one. This leads to a chain of incorrect > assertions which ends in the AccumulateNode NPE. > > I've rewriten my rules in order to JoinNode18 feeds only AccumulateNode25 > thus avoiding the NPE and returning to my user role. However I am not sure > if any CompositeSink starting at a JoinNode will have this or other problems > when being left or right modified. I hope this information helps to solve > this problem. > > Best regards, > > Manuel Ortiz. > > > 2011/3/31 Wolfgang Laun <wolfgang.laun(a)gmail.com&gt; > >> >> >> 2011/3/31 Manuel Ortiz <manuel.ortizramos(a)gmail.com&gt; >> >>> Hi Wofgang: >>> >>> Thank youvery much for your response. I was replaying to Mauricio when >>> your email has arrived. I hope the test case is useful. >>> >>> >> Thanks. Files are attached to the JIRA and JIRA is now at "critical". >> -W >> >> >>> Best regards, >>> >>> Manuel Ortiz. >>> >>> >>> 2011/3/31 Wolfgang Laun <wolfgang.laun(a)gmail.com&gt; >>> >>>> Manuel, >>>> >>>> I have reported this (or a very similar) problem >>>> https://issues.jboss.org/browse/JBRULES-2887 with a small example to >>>> reproduce. >>>> >>>> The stack trace is not identical, so please try to reproduce this with >>>> a small test case; it is bound to happen with a rule (Test Negativo Alarma >>>> Acceso Portal Ubicacion UM) that modifies some fact that is used in an >>>> "accumulate" phrase, (If this pattern is different from the one I gave, I'll >>>> raise the issue priority to "critical".) >>>> >>>> Cheers >>>> Wolfgang >>>> >>>> >>>> 2011/3/30 Manuel Ortiz <manuel.ortizramos(a)gmail.com&gt; >>>> >>>>> Hello all! >>>>> >>>>> I am new in Drools but day by day, test by test, I think I get a bit >>>>> more knowledge of how the rule engine works from user point of view. I've >>>>> been adding rules to an alarm system, increasing the complexity and >>>>> functionality in several steps. Unfortunately in the last step I found the >>>>> following NullPointerException inside the rule engine... >>>>> >>>>> java.lang.NullPointerException >>>>> at >>>>> org.drools.reteoo.AccumulateNode.getFirstMatch(AccumulateNode.java:967) >>>>> at >>>>> org.drools.reteoo.AccumulateNode.modifyLeftTuple(AccumulateNode.java:329) >>>>> at >>>>> org.drools.reteoo.SingleLeftTupleSinkAdapter.propagateModifyChildLeftTuple(SingleLeftTupleSinkAdapter.java:239) >>>>> at >>>>> org.drools.reteoo.AccumulateNode.evaluateResultConstraints(AccumulateNode.java:640) >>>>> at >>>>> org.drools.reteoo.AccumulateNode.assertObject(AccumulateNode.java:270) >>>>> at org.drools.reteoo.BetaNode.modifyObject(BetaNode.java:312) >>>>> at >>>>> org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject(CompositeObjectSinkAdapter.java:460) >>>>> at >>>>> org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject(CompositeObjectSinkAdapter.java:428) >>>>> at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:160) >>>>> at >>>>> org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject(CompositeObjectSinkAdapter.java:460) >>>>> at >>>>> org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject(CompositeObjectSinkAdapter.java:428) >>>>> at >>>>> org.drools.reteoo.ObjectTypeNode.modifyObject(ObjectTypeNode.java:263) >>>>> at >>>>> org.drools.reteoo.EntryPointNode.modifyObject(EntryPointNode.java:172) >>>>> at >>>>> org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1442) >>>>> at >>>>> org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1349) >>>>> at >>>>> org.drools.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:183) >>>>> at >>>>> org.drools.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:196) >>>>> at >>>>> es.simcasva.alarmas.rules.Rule_Test_Negativo_Alarma_Acceso_Portal_Ubicacion_UM_0.defaultConsequence(Rule_Test_Negativo_Alarma_Acceso_Portal_Ubicacion_UM_0.java:18) >>>>> at >>>>> es.simcasva.alarmas.rules.Rule_Test_Negativo_Alarma_Acceso_Portal_Ubicacion_UM_0DefaultConsequenceInvoker.evaluate(Rule_Test_Negativo_Alarma_Acceso_Portal_Ubicacion_UM_0DefaultConsequenceInvoker.java:44) >>>>> at >>>>> org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:917) >>>>> at >>>>> org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:856) >>>>> at >>>>> org.drools.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1071) >>>>> at >>>>> org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:785) >>>>> at >>>>> org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:751) >>>>> at >>>>> org.drools.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:218) >>>>> >>>>> I've been trying to find the problem, and found a strange interaction >>>>> between three rules that makes the null pointer to appear. The alarm system >>>>> has many rules now and it is difficult to simplify the scenario, so I just >>>>> would like to know what is the funcion of AccumulateNode object in order to >>>>> have an idea of the NullPointerException possible cause. >>>>> >>>>> Can anyone help me? >>>>> >>>>> Thank you in advance for your time. >>>>> >>>>> Regards, >>>>> >>>>> Manuel Ortiz. >>>>> >>>>> >>>>> _______________________________________________ >>>>> 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 >>>> >>>> >>> >>> _______________________________________________ >>> 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 >> >> > > _______________________________________________ > 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