[rules-users] Fusion: Null pointer exception when using sliding windows

[burmanator]

The missing ":" was just a typo in my transcribing. I'm running my code in a
virtual machine so I couldn't copy and paste and have to hand type
everything out.  I go through and check the knowledge builder for errors by
checking the size of KnowledgeBuilder.getErrors() and if the size is greater
then 0, display the error. However nothing comes up.

I'm running Drools 5.5.0.Final that I just downloaded recently.

the DRL I'm using consists of:

package testing2;

import test2.*; 
import java.util.*;
import org.drools.*;

declare Foo
@role(event)
@timestamp(Start)
@duration(Duration)
end

rule test
when
$primary : Foo($name : Name) over window:length(24)
$prev : ArrayList(size<1) from collect ( Foo(Name == $name, this before
$primary)) 
then
System.out.println("Found name: " + $name);
end


The error in the console that gets spit back out is:

java.land.NullPointerException
   at org.drools.core.util.index.RightTupleIndexHashTable.remove
(RightTupleIndexHashTable.java : 363)
   at org.drools.reteoo.AccumulateNode.retractRightTuple
(AccumulateNode.java : 318)
   at org.drools.rule.SlidingLengthWindow.assertFact
(SlidingLengthWindow.java : 116)
   at org.drools.rule.BehaviorManager.assertFact (BehaviorManager.java : 94)
   at org.drools.reteoo.WindowNode.assertObject (WindowNode.java : 167)
   at org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateAssertObject
(CompositeObjectSinkAdapter.java : 497)
   at org.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject
(CompositeObjectSinkAdapter.java : 382)
   at org.drools.reteoo.ObjectTypeNode.assertObject (ObjectTypeNode.java :
235)
   at org.drools.reteoo.EntryPointNode.assertObject (EntryPointNode.java :
240)
   at org.drools.common.NamedEntryPoint.insert (NamedEntryPoint.java : 350)
   at org.drools.common.NamedEntryPoint.insert (NamedEntryPoint.java : 311)
   at org.drools.common.AbstractWorkingMemory.insert
(AbstractWorkingMemory.java : 903)
   at org.drools.common.AbstractWorkingMemory.insert
(AbstractWorkingMemory.java : 847)
   at
org.drools.impl.StatefulKnowledgeSessionImpl.insert(StatefulKnowledgeSessionImpl.java
: 269)
   at test2.Engine2.main (ngine2.java : 78)

that last line points to my main class where I add the events into the
knowledge session.

When I change "over window:length(24)" to "over window:time(21d)" (my sample
data is about 22 days old now) I get the error:

org.drools.RuntimeDroolsException : Unexpected exception executing action
org.drools.rule.SlidingTimeWIndow$BehaviorExpireWMAction at 491cc367
   at org.drools.common.AbstractWorkingMemory.executeQueuedActions
(AbstractWorkingMemory.java : 995)
   at org.drools.common.NamedEntryPoint.insert (NamedEntryPoint.java : 362)
   at org.drools.common.NamedEntryPoint.insert (NamedEntryPoint.jaba : 311)
   at org.drools.common.AbstractWorkingMemory.insert
(AbstractWorkingMemory.java : 903)
   at org.drools.common.AbstractWorkingMemory.insert
(AbstractWorkingMemory.java : 847)
   at org.drools.impl.StatefulKnowledgeSessionImpl.insert
(StatefulKnowledgeSessionImpl.java : 269)
   at test2.Engine2.main (Engine2.java : 78)
Caused by: java.lang.NullPointerException
   at
org.drools.core.util.index.RightTupleIndexHashTable.remove(RightTupleIndexHashTable.java
: 363)
   at org.drools.reteoo.AccumulateNode.retractRightTuple
(AccumulateNode.java : 318)
   at org.drools.rule.SlidingTimeWindow.expireFacts(SlidingTimeWindow.java :
189)
   at org.drools.rule.SlidingTimeWindow$BehaviorExpireWMAction.execute
(SlidingTimeWindow.java : 471)
   at org.drools.common.AbstractWorkingMemory.executeQueuedActions
(AbstractWorkingMemory.java : 993)
... 6 more


When I get rid of any over window statements, everything runs just fine.



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