[rules-users] Combined OR/NOT Rules results in NullPointerException

[Wolfgang Laun]

If you mean

when
   ( $value1: Value(...)
     not Input(...)
   or
     $value2: Value(...)
     not Input(...)  )

  $solution: SolutionInput(...)
then
...

you'll have to use parentheses. If not, what *do* you mean?
-W


On 3/29/10, Sebastian Furth <sebastian.furth at googlemail.com> wrote:
> Hello,
>
> i've already mailed last week with the same problem and with your help I was
> able to locate the source of the following NullPointerException which
> happens if we try to insert the Fact "knocking" (@see Source Code of the
> Java Class here: http://www.pastie.org/private/juv7hh7rxahpluo5agu3q) :
>
> *java.lang.NullPointerException
>     at org.drools.reteoo.LeftTuple.get(LeftTuple.java:265)
>     at org.drools.reteoo.LeftTuple.get(LeftTuple.java:300)
>     at
> org.drools.rule.VariableRestriction$ObjectVariableContextEntry.updateFromTuple(VariableRestriction.java:320)
>     at
> org.drools.common.SingleBetaConstraints.updateFromTuple(SingleBetaConstraints.java:119)
>     at org.drools.reteoo.NotNode.assertLeftTuple(NotNode.java:98)
>     at
> org.drools.reteoo.SingleLeftTupleSinkAdapter.doPropagateAssertLeftTuple(SingleLeftTupleSinkAdapter.java:117)
>     at
> org.drools.reteoo.SingleLeftTupleSinkAdapter.propagateAssertLeftTuple(SingleLeftTupleSinkAdapter.java:34)
>     at org.drools.reteoo.NotNode.assertLeftTuple(NotNode.java:123)
>     at
> org.drools.reteoo.CompositeLeftTupleSinkAdapter.doPropagateAssertLeftTuple(CompositeLeftTupleSinkAdapter.java:145)
>     at
> org.drools.reteoo.CompositeLeftTupleSinkAdapter.createAndPropagateAssertLeftTuple(CompositeLeftTupleSinkAdapter.java:57)
>     at
> org.drools.reteoo.LeftInputAdapterNode.assertObject(LeftInputAdapterNode.java:142)
>     at
> org.drools.reteoo.SingleObjectSinkAdapter.propagateAssertObject(SingleObjectSinkAdapter.java:42)
>     at org.drools.reteoo.AlphaNode.assertObject(AlphaNode.java:147)
>     at
> org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateAssertObject(CompositeObjectSinkAdapter.java:360)
>     at
> org.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject(CompositeObjectSinkAdapter.java:344)
>     at
> org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:185)
>     at
> org.drools.reteoo.EntryPointNode.assertObject(EntryPointNode.java:146)
>     at
> org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:1046)
>     at
> org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:1001)
>     at
> org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:788)
>     at
> org.drools.impl.StatefulKnowledgeSessionImpl.insert(StatefulKnowledgeSessionImpl.java:216)
>     at de.d3web.we.drools.DroolsAction.addFacts(DroolsAction.java:334)
> *
>
> The source of the problem is the following rule:
>
> *rule "R50"
>   when
>     $value1 : Value(value == "knocking")
>     not Input(name == "Engine noises" && values contains $value1)
>     or
>     $value2 : Value(value == "ringing")
>     not Input(name == "Engine noises" && values contains $value2)
>     $solution : SolutionInput(name == "Bad ignition timing")
>   then
>     $solution.setValue(N3);
> end
> *
>
> Could you please tell me how I have to formulate the rule to avoid the
> NullPointerException while inserting the fact?
>
> Thank you in advance for your help.
>
> Best regards
>
> Sebastian Furth
>