[rules-users] Exception executing consequence for rule xxx in yyy: java.lang.RuntimeException: unable to access field

[Chang Liu]

A rule to repro this situation:

The rule:
...
rule "Assignment In Action Test"
    when
    	obj : Foo()
    then
    	obj.x = 1;
        System.out.println("Rule Fired!");
end
...

Definition of class Foo:
public class Foo {
	public int x;
	public int getX() {
		return x;
	}
	public void setX(int x) {
		this.x = x;
	}
}

Objects been inserted:
Foo foo1 = new Foo();
foo1.x = 0;
Foo foo2 = new Foo();
Foo2.x = 1000;

Note that if only one Foo object is inserted, things work fine. If more than one Foo objects are inserted, we see this Exception:

Exception executing consequence for rule "Assignment In Action Test" in com.sample: java.lang.RuntimeException: unable to access field
	at org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)
	at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1283)
	at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:1209)
	at org.drools.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1442)
	at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:710)
	at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:674)
	at org.drools.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:230)
	at com.sample.AssignmentInActionTestMain.main(AssignmentInActionTestMain.java:37)
Caused by: java.lang.RuntimeException: unable to access field
	at org.mvel2.optimizers.impl.refl.nodes.DynamicFieldAccessor.setValue(DynamicFieldAccessor.java:66)
	at org.mvel2.optimizers.impl.refl.nodes.IndexedVariableAccessor.setValue(IndexedVariableAccessor.java:43)
	at org.mvel2.compiler.CompiledAccExpression.setValue(CompiledAccExpression.java:59)
	at org.mvel2.ast.DeepAssignmentNode.getReducedValueAccelerated(DeepAssignmentNode.java:92)
	at org.mvel2.MVELRuntime.execute(MVELRuntime.java:85)
	at org.mvel2.compiler.CompiledExpression.getValue(CompiledExpression.java:126)
	at org.mvel2.MVEL.executeExpression(MVEL.java:930)
	at org.drools.base.mvel.MVELConsequence.evaluate(MVELConsequence.java:101)
	at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1273)
	... 6 more
Caused by: java.lang.NullPointerException
	at org.mvel2.DataConversion.convert(DataConversion.java:118)
	at org.mvel2.optimizers.impl.refl.nodes.DynamicFieldAccessor.setValue(DynamicFieldAccessor.java:61)
	... 14 more

-----Original Message-----
From: rules-users-bounces at lists.jboss.org [mailto:rules-users-bounces at lists.jboss.org] On Behalf Of Wolfgang Laun
Sent: Wednesday, January 16, 2013 10:35 AM
To: Rules Users List
Subject: Re: [rules-users] Exception executing consequence for rule xxx in yyy: java.lang.RuntimeException: unable to access field

What's the type of $billingOutputRuleContext.retroPreviousBillAmount?

On 16/01/2013, magaram <magaram at deltadentalmi.com> wrote:
> The behavior stated seems very erratic as other similar rules are 
> executing.
> Also note that the fields in the consequence have a visibility of public.
> Are there any known issues surrounding this?
>
>
>
> --
> View this message in context:
> http://drools.46999.n3.nabble.com/Exception-executing-consequence-for-
> rule-xxx-in-yyy-java-lang-RuntimeException-unable-to-access-field-tp40
> 21553p4021576.html Sent from the Drools: User forum mailing list 
> archive at Nabble.com.
> _______________________________________________
> rules-users mailing list
> rules-users at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users
>
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