[jboss-jira] [JBoss JIRA] Created: (JBRULES-1089) Getting "could not access property ('=')" for a valid rule.

Thu Aug 16 02:59:01 EDT 2007

Getting "could not access property ('=')" for a valid rule.
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                 Key: JBRULES-1089
                 URL: http://jira.jboss.com/jira/browse/JBRULES-1089
             Project: JBoss Rules
          Issue Type: Bug
      Security Level: Public (Everyone can see)
          Components: Drl Parser/Builder
    Affects Versions:  4.0.0.GA
         Environment: WinXP, Java 1.6.0 (Sun), running within Eclipse 3.2.2
            Reporter: Arsalan Zaidi
         Assigned To: Mark Proctor

From: rules-users-bounces at lists.jboss.org on behalf of Edson Tirelli [tirelli at post.com]
Sent: 13 August 2007 22:16
To: Rules Users List
Subject: Re: [rules-users] could not access property ('=')

Attachments: ATT426765.txt

   This looks like an MVEL issue, since your expression is being converted into an MVEL predicate. May I ask you please to open a JIRA for that bug?

   Meanwhile, a workaround that shall work for you and may give you improved perf is to split your pattern into 2 patterns using the from keyword: 

when

           $dto : DTO( )

           W250_4_1( value in ("0" ,"1" ,"6" ,"7" ,"A" ,"C" ,"D" ,"G" ,"L" ,"M" ,"P" ,"Q" ,"S" ,"V" ,"Z" ) ) from $dto.w250_4_1

then

   Thanks, and hope it helps.

   Edson

2007/8/13, Arsalan S. Zaidi < arsalan.zaidi at capgemini.com>:
  Hi.

  I've currently evaluating Drools 4.0 for a project of ours and I'm running into some problems.

  I have a rule which looks like this:

  rule "W250.42 Editable"

        when

              DTO(w250_4_1.value in ("0" ,"1" ,"6" ,"7" ,"A" ,"C" ,"D" ,"G" ,"L" ,"M" ,"P" ,"Q" ,"S" ,"V" ,"Z" ) )

        then

              System.out.println ("0" );

              Action action = createAction("W250.42" , false , true );

              retList.add(action); 

  end 

  both DTO and w250_4_1 are extremely simple beans. w250_4_1 just has 1 property 'value' which is a String and DTO has one property w250_4_1 which is the bean w250_4_1 .

  Now when I put "0" into w250_4_1 then everything works fine. The rule is true and the 'then' portion is executed. However, if I set w250_4_1 to "6" (which is also present in the in (...)) then I get the following error.

  org.drools.RuntimeDroolsException : Exception executing predicate org.drools.base.mvel.MVELPredicateExpression at 118fa47

        at org.drools.rule.PredicateConstraint.isAllowed(PredicateConstraint.java:197 )

        at org.drools.reteoo.AlphaNode.assertObject(AlphaNode.java:122 )

        at org.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject(CompositeObjectSinkAdapter.java:317 )

        at org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:168 )

        at org.drools.reteoo.Rete.assertObject(Rete.java:168 )

        at org.drools.reteoo.ReteooRuleBase.assertObject( ReteooRuleBase.java:190) 

        at org.drools.reteoo.ReteooWorkingMemory.doInsert(ReteooWorkingMemory.java:70 )

        at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:848 )

        at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:822 )

        at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:623 )

        at com.sample.DroolsTest.main( DroolsTest.java:34)

  Caused by: org.mvel.PropertyAccessException: failed to access property: <<==>> in: class com.sample.DTOShadowProxy

        at org.mvel.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:137 )

        at org.mvel.optimizers.impl.refl.ReflectiveAccessorOptimizer.optimizeAccessor(ReflectiveAccessorOptimizer.java:96 )

        at org.mvel.ASTNode.getReducedValueAccelerated(ASTNode.java:194 )

        at org.mvel.ast.Or.getReducedValueAccelerated(Or.java:18 )

        at org.mvel.MVELRuntime.execute( MVELRuntime.java:87)

        at org.mvel.CompiledExpression.getValue( CompiledExpression.java:98) 

        at org.mvel.MVEL.executeExpression( MVEL.java:202)

        at org.drools.base.mvel.MVELPredicateExpression.evaluate(MVELPredicateExpression.java:36 )

        at org.drools.rule.PredicateConstraint.isAllowed(PredicateConstraint.java:191 )

        ... 10 more

  Caused by: org.mvel.PropertyAccessException: could not access property ('=') 

        at org.mvel.optimizers.impl.refl.ReflectiveAccessorOptimizer.getBeanProperty(ReflectiveAccessorOptimizer.java:252 )

        at org.mvel.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:106 )

        ... 18 more

  If I keep w250_4_1 as "0", but move "0" in the rule to any other place place in the in() list (e.g. in ("1","0",...), then I get a similar error.

  I get similar errors when trying to use 'not in' in the same circumstance, except that then the property is ('!')

  What seems to be the issue?

  Thanks in advance!

  Regards,

  --Arsalan

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-- 
  Edson Tirelli
  Software Engineer - JBoss Rules Core Developer
  Office: +55 11 3529-6000
  Mobile: +55 11 9287-5646
  JBoss, a division of Red Hat @ www.jboss.com 

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