8:36 a.m.
I am using Drools 5.1.1.
Do you want me to package a small maven project exhibiting that error,
and post a Jira?
Bruno.
Le 08/09/2011 15:04, Edson Tirelli a écrit :
It looks like a bug, as it should not raise a NPE no matter
what.... which version of Drools are you using?
Edson
2011/9/8 Bruno Freudensprung <bruno.freudensprung(a)temis.com
<mailto:bruno.freudensprung@temis.com>>
Hi Edson, hi all,
To stick to the subject, I have a strange problem (stack trace in
PS) with a rule containing two accumulate calls, the result of the
first one is re-injected as the input of the second one. Those
accumulate functions are "home made".
The first one (tokenize) returns an ArrayList of Token objects
built by tokenizing the "text" of the Sentence objects.
The second one (build10windows) returns an ArrayList of Window
objects, each one them containing 10 consecutive tokens.
Here is the rule
when
$budget : ManualAnnotation(text == "something")
*$tokens* : java.util.ArrayList() *from accumulate *($s :
Sentence(), *tokenize*($s))
$windows : java.util.ArrayList() *from accumulate *($t :
Token() *from $tokens*, *build10windows*($t))
# removed a part here but the problem occurs even without
this part
then
retract($budget);
Is there anything else one should be aware of when implementing
their own accumulate function? I mean things related to the fact
that "classical" accumulate functions (sum, average) return an
immutable object that does not share anything with the context object.
Although accumulate, reverse, and getResult methods of my
functions are unit tested, I suspect something that could be
related to stateless/stateful considerations.
What do you think?
Many thanks,
Bruno.
PS :
The stack trace is:
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.command.runtime.rule.FireAllRulesCommand.execute(FireAllRulesCommand.java:99)
at
org.drools.command.runtime.rule.FireAllRulesCommand.execute(FireAllRulesCommand.java:33)
at
org.drools.command.runtime.BatchExecutionCommandImpl.execute(BatchExecutionCommandImpl.java:159)
at
org.drools.command.runtime.BatchExecutionCommandImpl.execute(BatchExecutionCommandImpl.java:81)
at
org.drools.impl.StatelessKnowledgeSessionImpl.execute(StatelessKnowledgeSessionImpl.java:262)
... 5 more
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.ObjectTypeNode.retractObject(ObjectTypeNode.java:240)
at
org.drools.reteoo.EntryPointNode.retractObject(EntryPointNode.java:231)
at
org.drools.common.AbstractWorkingMemory.retract(AbstractWorkingMemory.java:1288)
at
org.drools.base.DefaultKnowledgeHelper.retract(DefaultKnowledgeHelper.java:201)
at
org.drools.base.DefaultKnowledgeHelper.retract(DefaultKnowledgeHelper.java:214)
at
defaultpkg.Rule_Display_windows_0.defaultConsequence(Rule_Display_windows_0.java:21)
at
defaultpkg.Rule_Display_windows_0DefaultConsequenceInvoker.evaluate(Rule_Display_windows_0DefaultConsequenceInvoker.java:29)
at
org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:917)
... 15 more
Bruno.
Le 24/08/2011 16:21, Edson Tirelli a écrit :
>
> Yes, evaluation is incremental, so for every new fact, it will
> call accumulate() and getResult().
>
> We do want to reduce the calls to getResult(), improving
> performance, but it is not easy to figure out a way, as from an
> engine perspective, it never knows when the application is done
> inserting facts and it is time to calculate the final result.
>
> Edson
>
> 2011/8/24 Bruno Freudensprung <bruno.freudensprung(a)temis.com
> <mailto:bruno.freudensprung@temis.com>>
>
> Hi,
>
> While testing my custom accumulation function I noticed an
> unexpected
> behavior (th'ats of course a personal point of view).
> It seems that Drools 5.1 calls accumulate(...) and
> getResult(...) as
> many times as the number of accumulated facts (accumulate,
> getResult,
> accumulate, getResult, etc...).
> Is it supposed to work like this?
>
> Best regards,
>
> Bruno.
>
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>
>
>
> --
> Edson Tirelli
> JBoss Drools Core Development
> JBoss by Red Hat @ www.jboss.com <http://www.jboss.com>
>
>
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JBoss Drools Core Development
JBoss by Red Hat @ www.jboss.com <http://www.jboss.com>
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