[rules-users] Question about custom accumulation functions
Edson Tirelli
ed.tirelli at gmail.com
Thu Sep 8 11:17:23 EDT 2011
Bruno,
Can you please test it with latest snapshot? If it is still a problem,
then please open a JIRA and provide the test to reproduce it...
https://hudson.jboss.org/jenkins/view/Drools%20jBPM/job/drools/lastSuccessfulBuild/artifact/drools-distribution/target/
Thanks,
Edson
2011/9/8 Bruno Freudensprung <bruno.freudensprung at temis.com>
> **
>
> 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 at 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 at 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.
>>>
>>> _______________________________________________
>>> rules-users mailing list
>>> rules-users at lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/rules-users
>>>
>>
>>
>>
>> --
>> Edson Tirelli
>> JBoss Drools Core Development
>> JBoss by Red Hat @ www.jboss.com
>>
>>
>> _______________________________________________
>> rules-users mailing listrules-users at lists.jboss.orghttps://lists.jboss.org/mailman/listinfo/rules-users
>>
>>
>>
>> _______________________________________________
>> rules-users mailing list
>> rules-users at lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/rules-users
>>
>>
>
>
> --
> Edson Tirelli
> JBoss Drools Core Development
> JBoss by Red Hat @ www.jboss.com
>
>
> _______________________________________________
> rules-users mailing listrules-users at lists.jboss.orghttps://lists.jboss.org/mailman/listinfo/rules-users
>
>
>
> _______________________________________________
> rules-users mailing list
> rules-users at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users
>
>
--
Edson Tirelli
JBoss Drools Core Development
JBoss by Red Hat @ www.jboss.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.jboss.org/pipermail/rules-users/attachments/20110908/769b49c6/attachment.html
More information about the rules-users
mailing list