[rules-users] Getting facts from external source using 'from' and parametrized method call

[Przemysław Różycki]

Of course, you can get rid of 'pre rule'. I forgot to delete it.

Best regards,
Przemek

Przemysław Różycki pisze:
> Hi,
> 
> I mean, I checked the global and it was set.
> 
> I'm attaching the code, that causes the problem (Java and DRL). You need 
> just to set a proper path to DRL file while setting file property in 
> Java file. I think, the global is set in proper way.
> In DRL, depending which rule is commented/uncommented, the code works or 
> not.
> 
> Best regards,
> Przemek
> 
> Jaroslaw Kijanowski pisze:
>> And did the stack trace change? Can you post more details (drl, java 
>> src)?
>>
>> Przemysław Różycki wrote:
>>> Yes, I did. This was the first thing I've checked.
>>>
>>> Best regards,
>>> Przemek
>>>
>>> Jaroslaw Kijanowski pisze:
>>>> Did you set the global on your session?
>>>>
>>>> http://downloads.jboss.com/drools/docs/4.0.7.19894.GA/html_single/index.html#d0e948 
>>>>
>>>>
>>>> Cheers
>>>>
>>>> Przemysław Różycki wrote:
>>>>> Sorry for responsing myself, but I'm still working on it and found 
>>>>> that when factSource is a fact, not global, the rule works very 
>>>>> well. I mean, this rule works fine:
>>>>>
>>>>> rule "My Rule"
>>>>>   when
>>>>>     $factSrc : FactSource(  )
>>>>>     $fact : Fact(  ) from $factSrc.getSomeFacts("a","b","c")
>>>>>   then
>>>>>     // do something
>>>>> end
>>>>>
>>>>> so what's the difference between invocation on global object and 
>>>>> invocation on fact object? Why the first one doesn't work and the 
>>>>> second one works?
>>>>>
>>>>> Best regards,
>>>>> Przemek
>>>>>
>>>>>
>>>>> Przemysław Różycki pisze:
>>>>>> Hi,
>>>>>>
>>>>>> could I ask for some advice, please, how to use a parametrized 
>>>>>> method call to get some data using 'from' element in LHS.
>>>>>>
>>>>>> To be more precise, I would like to do something like this:
>>>>>>
>>>>>> rule "My Rule"
>>>>>>   when
>>>>>>     $fact : Fact(  ) from factSource.getSomeFacts("a","b","c")
>>>>>>   then
>>>>>>     // do something
>>>>>> end
>>>>>>
>>>>>> where factSource is for example some global and 
>>>>>> getSomeFacts(String,String,String) is a parametrized method that 
>>>>>> returns some array of Fact objects.
>>>>>>
>>>>>> Unfortunately, when I try to launch the following rule I have an 
>>>>>> error:
>>>>>>
>>>>>> Exception in thread "main" org.mvel.PropertyAccessException: 
>>>>>> unable to resolve property: factSource.getSomeFacts("a","b","c")
>>>>>>     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 com.sample.DroolsTest6.main(DroolsTest6.java:29)
>>>>>> 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) 
>>>>>>
>>>>>>     ... 21 more
>>>>>>
>>>>>> Documentation says:
>>>>>>
>>>>>> "The from Conditional Element allows users to specify a source for 
>>>>>> patterns to reason over. This allows the engine to reason over 
>>>>>> data not in the Working Memory. This could be a sub-field on a 
>>>>>> bound variable or the results of a method call."
>>>>>>
>>>>>> so I assume that it is possible to do what I want. If not, could I 
>>>>>> ask for an advice of some workaround, please?
>>>>>>
>>>>>> Best regards,
>>>>>
>>>>> _______________________________________________
>>>>> rules-users mailing list
>>>>> rules-users at lists.jboss.org
>>>>> https://lists.jboss.org/mailman/listinfo/rules-users
>>>>>
>>>>
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