I have encountered the following issue when running a rule that has more than 1 collect from a same collection.

I have the following two rules:

rule "filter sentences based on existence of attributes"

                when

                                IPhoneQueryCmd(State.POPULATE == state, $tidt: targetId)                     

                                $attributeFilteredSentences:     ArrayList()          

                                                                                                from collect (IPhoneSentences.Sentence(                                                                                                                                                                                            

                                                                                                                                ( (descriptor.targetPrivatename == false) || (descriptor.targetPrivatename == $cmt.sentenceFilters.targetPrivatename)  ) &&

                                                                                                                                ( (descriptor.targetSurename == false) || (descriptor.targetSurename == $cmt.sentenceFilters.targetSurename)  ) &&

                                                                                                                                ( (descriptor.targetFullname == false) || (descriptor.targetFullname == $cmt.sentenceFilters.targetFullname)  ) &&

                                                                                                                                ( (descriptor.requesterPrivatename == false) || (descriptor.requesterPrivatename == $cmt.sentenceFilters.requesterPrivatename)  ) &&

                                                                                                                                ( (descriptor.requesterSurename == false) || (descriptor.requesterSurename == $cmt.sentenceFilters.requesterSurenamename)  ) &&

                                                                                                                                ( (descriptor.requesterFullname == false) || (descriptor.requesterFullname == $cmt.sentenceFilters.requesterFullname)  ) &&

                                                                                                                                ( (descriptor.time == false) || (descriptor.time == $cmt.sentenceFilters.time)  ) &&

                                                                                                                                ( (descriptor.subject == false) || (descriptor.subject == $cmt.subject)  )

                                                                                                                                ))

                then                                                                                     

end       

rule "Iphone targets information update - QUERY_AVAILABILITY" extends "filter sentences based on existence of attributes"

when

            $qc:              IPhoneQueryCmd(State.POPULATE == state, $tid: targetId)

            $cm:              ConditionMatrix($taskId: taskId,

                                                            targetId == $tid,

                                                            contextIntention == EContextIntention.QUERY_AVAILABILITY,

                                                            $timeConstraintType: requesterConstraint.constraintRequestType)

            $targetResponse:        ArrayList()

from collect (IPhoneSentences.Sentence(descriptor.intentions.intention contains EContextIntention.QUERY_AVAILABILITY.name)

from  $attributeFilteredSentences)                                                                       

then

//do something

End

This works fine but once I wish to add a second filtered ArrayList using $attributeFilteredSentences I get a null pointer exception.

For example I will add an exact similar filter condition but change the result var name (I called it $dummyVar)

rule "Iphone targets information update - QUERY_AVAILABILITY" extends "filter sentences based on existence of attributes"

when

            $qc:              IPhoneQueryCmd(State.POPULATE == state, $tid: targetId)

            $cm:              ConditionMatrix($taskId: taskId,

                                                            targetId == $tid,

                                                            contextIntention == EContextIntention.QUERY_AVAILABILITY,

                                                            $timeConstraintType: requesterConstraint.constraintRequestType)

            $targetResponse:        ArrayList()

from collect (IPhoneSentences.Sentence(descriptor.intentions.intention contains EContextIntention.QUERY_AVAILABILITY.name)

from  $attributeFilteredSentences)                                                                       

            $dummyVar:        ArrayList()

from collect (IPhoneSentences.Sentence(descriptor.intentions.intention contains EContextIntention.QUERY_AVAILABILITY.name)

from  $attributeFilteredSentences)                                                                      

then

//do something

End

In this case I get the following exception stack:

org.drools.runtime.rule.ConsequenceException: rule: Iphone dialog sentence - QUERY_AVAILABILITY

      at org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)

      at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:927)

      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)

      at org.drools.impl.StatelessKnowledgeSessionImpl.execute(StatelessKnowledgeSessionImpl.java:302)

      at com.delegatecom.task.TaskStatelessSession.testRunRules(TaskStatelessSession.java:122)

      at com.delegatecom.task.TaskStatelessSession.internalTestNextStep(TaskStatelessSession.java:98)

      at com.delegatecom.task.TaskStatelessSession.testNextStep(TaskStatelessSession.java:76)

      at com.delegatecom.test.AtoB.testStatelessRule(AtoB.java:99)

      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

      at java.lang.reflect.Method.invoke(Method.java:597)

      at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)

      at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)

      at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)

      at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)

      at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)

      at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)

      at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)

      at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)

      at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)

      at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)

      at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)

      at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)

      at org.junit.runners.ParentRunner.run(ParentRunner.java:236)

      at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46)

      at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)

      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)

      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)

      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)

      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

Caused by: java.lang.NullPointerException

      at org.drools.reteoo.AccumulateNode.getFirstMatch(AccumulateNode.java:967)

      at org.drools.reteoo.AccumulateNode.splitList(AccumulateNode.java:920)

      at org.drools.reteoo.AccumulateNode.removePreviousMatchesForLeftTuple(AccumulateNode.java:874)

      at org.drools.reteoo.AccumulateNode.retractLeftTuple(AccumulateNode.java:205)

      at org.drools.reteoo.CompositeLeftTupleSinkAdapter.doPropagateRetractLeftTuple(CompositeLeftTupleSinkAdapter.java:238)

      at org.drools.reteoo.CompositeLeftTupleSinkAdapter.propagateRetractLeftTupleDestroyRightTuple(CompositeLeftTupleSinkAdapter.java:138)

      at org.drools.reteoo.AccumulateNode.retractLeftTuple(AccumulateNode.java:212)

      at org.drools.reteoo.CompositeLeftTupleSinkAdapter.doPropagateRetractLeftTuple(CompositeLeftTupleSinkAdapter.java:238)

      at org.drools.reteoo.CompositeLeftTupleSinkAdapter.propagateRetractLeftTuple(CompositeLeftTupleSinkAdapter.java:122)

      at org.drools.reteoo.JoinNode.retractLeftTuple(JoinNode.java:163)

      at org.drools.reteoo.SingleLeftTupleSinkAdapter.doPropagateRetractLeftTuple(SingleLeftTupleSinkAdapter.java:217)

      at org.drools.reteoo.SingleLeftTupleSinkAdapter.propagateRetractLeftTuple(SingleLeftTupleSinkAdapter.java:91)

      at org.drools.reteoo.JoinNode.retractLeftTuple(JoinNode.java:163)

      at org.drools.reteoo.SingleLeftTupleSinkAdapter.doPropagateRetractLeftTuple(SingleLeftTupleSinkAdapter.java:217)

      at org.drools.reteoo.SingleLeftTupleSinkAdapter.propagateRetractLeftTupleDestroyRightTuple(SingleLeftTupleSinkAdapter.java:107)

      at org.drools.reteoo.AccumulateNode.retractLeftTuple(AccumulateNode.java:212)

      at org.drools.reteoo.CompositeLeftTupleSinkAdapter.doPropagateRetractLeftTuple(CompositeLeftTupleSinkAdapter.java:238)

      at org.drools.reteoo.CompositeLeftTupleSinkAdapter.propagateRetractLeftTuple(CompositeLeftTupleSinkAdapter.java:122)

      at org.drools.reteoo.JoinNode.retractLeftTuple(JoinNode.java:163)

      at org.drools.reteoo.ModifyPreviousTuples.retractTuples(ModifyPreviousTuples.java:111)

      at org.drools.reteoo.EntryPointNode.modifyObject(EntryPointNode.java:176)

      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 com.delegatecom.rules.drl.Rule_Iphone_dialog_sentence___QUERY_AVAILABILITY_0.defaultConsequence(Rule_Iphone_dialog_sentence___QUERY_AVAILABILITY_0.java:27)

      at com.delegatecom.rules.drl.Rule_Iphone_dialog_sentence___QUERY_AVAILABILITY_0DefaultConsequenceInvoker.evaluate(Rule_Iphone_dialog_sentence___QUERY_AVAILABILITY_0DefaultConsequenceInvoker.java:65)

      at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:917)

      ... 33 more

Any idea what this can be?

Regards,

Hezi