[rules-users] DAO call in LHS

[techy]

I tried following simple rule with dao call and still no luck. getting
"org.mvel.PropertyAccessException: unable to resolve property:
dao.getList()".  could not figure out what is wrong. some help please.

rule "Test DAo call"
when 
	count : List(size > 0) from dao.getList()
then 
	System.out.println("DAO call is successful!");
end

dao.getList() definition:


 public List<Integer> getList(){
        return Collections.EMPTY_LIST;
    }

Exception stackTRace:

org.mvel.PropertyAccessException: unable to resolve property: dao.getList()
	at
org.mvel.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:295)
	at
org.mvel.optimizers.impl.refl.ReflectiveAccessorOptimizer.optimizeAccessor(ReflectiveAccessorOptimizer.java:110)
	at
org.mvel.ast.VariableDeepPropertyNode.getReducedValueAccelerated(VariableDeepPropertyNode.java:26)
	at
org.mvel.ast.PropertyASTNode.initializePropertyNode(PropertyASTNode.java:70)
	at
org.mvel.ast.PropertyASTNode.getReducedValueAccelerated(PropertyASTNode.java:24)
	at org.mvel.MVELRuntime.execute(MVELRuntime.java:90)
	at org.mvel.CompiledExpression.getValue(CompiledExpression.java:111)
	at org.mvel.MVEL.executeExpression(MVEL.java:252)
	at
org.drools.base.dataproviders.MVELDataProvider.getResults(MVELDataProvider.java:55)
	at org.drools.reteoo.FromNode.assertTuple(FromNode.java:68)
	at
org.drools.reteoo.SingleTupleSinkAdapter.createAndPropagateAssertTuple(SingleTupleSinkAdapter.java:55)
	at
org.drools.reteoo.LeftInputAdapterNode.assertObject(LeftInputAdapterNode.java:116)
	at
org.drools.reteoo.SingleObjectSinkAdapter.propagateAssertObject(SingleObjectSinkAdapter.java:22)
	at org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:162)
	at org.drools.reteoo.Rete.assertObject(Rete.java:175)
	at org.drools.reteoo.ReteooRuleBase.assertObject(ReteooRuleBase.java:192)
	at
org.drools.reteoo.ReteooWorkingMemory$WorkingMemoryReteAssertAction.execute(ReteooWorkingMemory.java:181)
	at
org.drools.common.AbstractWorkingMemory.executeQueuedActions(AbstractWorkingMemory.java:1312)
	at
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:915)
	at
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:883)
	at
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:684)
	at
org.drools.reteoo.ReteooStatelessSession.execute(ReteooStatelessSession.java:160)
	at DAOCallTest.main()
Caused by: java.lang.NullPointerException
	at
org.mvel.optimizers.impl.refl.ReflectiveAccessorOptimizer.getMethod(ReflectiveAccessorOptimizer.java:530)
	at
org.mvel.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:261)
	... 22 more


Michal Bali-2 wrote:
> 
> this blog post may be of use
> http://blog.athico.com/2007/06/chained-from-accumulate-collect.html
> 
> 
> On Wed, Nov 26, 2008 at 9:08 PM, techy <techluver007 at gmail.com> wrote:
> 
>>
>> though I referred other thread about this topic, I'm not successful to
>> make
>> a
>> dao call.
>> I beg your pardon to ask again.
>>
>> 1. I want to pass the fact object to the dao function which returns
>> boolean.
>> I tried following rule and getting "
>> Unexpected token '$fact'" as eclipse compilation error. Please guide with
>> right syntax.
>> global RuleDAO dao;
>>
>> rule "test DAO call"
>>  $fact : Fact(some condition)
>>  fact : Fact(dao.isValid($fact))
>> then
>> #do something
>> end
>>
>> 2. Will be there any performance issue for above kind of rule?
>>
>> Thanks
>>
>> --
>> View this message in context:
>> http://www.nabble.com/DAO-call-in-LHS-tp20709043p20709043.html
>> Sent from the drools - user 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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> 

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