[rules-users] java.lang.NullPointerException when using a custom operator

[Wolfgang Laun]

This seems to be a bug in Drools, a regression introduced into 5.5.0;
it compiles in 5.[34].0

The rule uses the custom operator supersetOf, both operands are
java.util.Collection.

    //Results in a null pointer exception: Error: java.lang.NullPointerException
    $test2:    ArrayList()
            from collect (DummyTest (sentence.intentions supersetOf
external.intentions))

The stack trace:
Exception in thread "main" java.lang.NullPointerException
	at org.drools.rule.builder.MVELConstraintBuilder.buildVariableConstraint(MVELConstraintBuilder.java:90)
	at org.drools.rule.builder.PatternBuilder.addConstraintToPattern(PatternBuilder.java:823)
	at org.drools.rule.builder.PatternBuilder.addConstraintToPattern(PatternBuilder.java:736)
	at org.drools.rule.builder.PatternBuilder.buildRelationalExpression(PatternBuilder.java:721)
	at org.drools.rule.builder.PatternBuilder.buildExpression(PatternBuilder.java:673)
	at org.drools.rule.builder.PatternBuilder.buildCcdDescr(PatternBuilder.java:657)
	at org.drools.rule.builder.PatternBuilder.build(PatternBuilder.java:629)
	at org.drools.rule.builder.PatternBuilder.processConstraintsAndBinds(PatternBuilder.java:477)
	at org.drools.rule.builder.PatternBuilder.build(PatternBuilder.java:302)
	at org.drools.rule.builder.PatternBuilder.build(PatternBuilder.java:123)
	at org.drools.rule.builder.CollectBuilder.build(CollectBuilder.java:43)
	at org.drools.rule.builder.CollectBuilder.build(CollectBuilder.java:32)
	at org.drools.rule.builder.PatternBuilder.build(PatternBuilder.java:293)
	at org.drools.rule.builder.PatternBuilder.build(PatternBuilder.java:123)
	at org.drools.rule.builder.GroupElementBuilder.build(GroupElementBuilder.java:67)
	at org.drools.rule.builder.RuleBuilder.build(RuleBuilder.java:84)
	at org.drools.compiler.PackageBuilder.addRule(PackageBuilder.java:2830)
	at org.drools.compiler.PackageBuilder.compileRules(PackageBuilder.java:970)
	at org.drools.compiler.PackageBuilder.compileAllRules(PackageBuilder.java:879)
	at org.drools.compiler.PackageBuilder.addPackage(PackageBuilder.java:871)
	at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:466)
	at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:694)
	at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:51)
	at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:40)
	at hezi.Main.setup(Main.java:77)
	at hezi.Main.main(Main.java:129)

Cheers
-W



On 03/08/2013, hezis <hezis at delegatecom.com> wrote:
> the error I describes in a compilation error in the IDE and not in runtime
> so
> there is no stack trace other than the Error:
> java.lang.NullPointerException
> error indicated in the eclipse markers tab.
> If testing this in runtime can spread light on the matter i will do so (it
> will take some time to get it set)
>
>
>
> --
> View this message in context:
> http://drools.46999.n3.nabble.com/rules-users-java-lang-NullPointerException-when-using-a-custom-operator-tp4025287p4025290.html
> Sent from the Drools: User forum mailing list archive at Nabble.com.
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