[rules-users] could not access property ('=')

Thu Aug 16 02:59:38 EDT 2007

Hi.

Jira Bug created. http://jira.jboss.com/jira/browse/JBRULES-1089

BTW, the work around works just fine. 

Thanks!

--Arsalan

________________________________

From: rules-users-bounces at lists.jboss.org
[mailto:rules-users-bounces at lists.jboss.org] On Behalf Of Edson Tirelli
Sent: 13 August 2007 22:16
To: Rules Users List
Subject: Re: [rules-users] could not access property ('=')

   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:1
97 )

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

      at
org.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject(Compo
siteObjectSinkAdapter.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.jav
a:848 )

      at
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.jav
a:822 )

      at
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.jav
a: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.compileGetChai
n(ReflectiveAccessorOptimizer.java:137 )

      at
org.mvel.optimizers.impl.refl.ReflectiveAccessorOptimizer.optimizeAccess
or(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(MVELPredicateExpre
ssion.java:36 )

      at
org.drools.rule.PredicateConstraint.isAllowed(PredicateConstraint.java:1
91 )

      ... 10 more

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

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

      at
org.mvel.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChai
n(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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