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

Did you set the global on your session? http://downloads.jboss.com/drools/docs/4.0.7.19894.GA/html_single/index.h... 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(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users