[rules-users] peephole technique -> cast to java.lang.Number problem
Wolfgang Laun
wolfgang.laun at gmail.com
Mon Nov 4 01:43:04 EST 2013
You never know what an expression suffers when it is thrown into
the MVEL machinery, (Mario's continuing efforts notwithstanding).
Documentation is sparse...
To be on the safe side, I'd probably have written
rule "count old"
when
$le : LastEvent($ev: event )
$last: Event( this == $ev )
$old : Event( this before [1ms , 5s] $last )
then
System.out.println($old);
end
-W
On 03/11/2013, Alexander Wolf <mail at alexander-wolf.net> wrote:
> Okey I got a little further: This works:
>
> rule "count old"
> when
> $le : LastEvent($ts : event.timestamp)
> $old : Event(this before [1ms , 5s] $ts)
> then
> System.out.println($old);
> end
>
> but then why does this not work ?!
>
> rule "count old"
> when
> $le : LastEvent($event : event)
> $old : Event(this before [1ms , 5s] $event.timestamp)
> then
> System.out.println($old);
> end
>
> To me this seems to be a bug, that occurs as soon as I set an event as
> member of a fact (the LastEvent) -> implementing the peephole technique.
> At least I got it to do what I want...but not as "niceley..." as expected.
>
> -
>
>
> On 02 Nov 2013, at 18:11, Alexander Wolf <mail at alexander-wolf.net> wrote:
>
>> Drools 5.5.0 + Fusion / stateful session / STREAM mode
>>
>> Hi,
>>
>> I try to improve my rules using peephole technique (Thanks @W)
>> I think I got it right, but now I am stuck with a problem.
>>
>> I want to keep a reference to my latest inserted event. Problem: the rule
>> "print old" gives me an Exception (see below).
>> I think the peephole itself works pretty well, but somehow my Event Object
>> (POJO with: Date timestamp, int value) is making problems when I try to
>> use "before". (see marked line, when commenting it out, the rules run
>> alright)
>>
>> dialect "mvel"
>>
>> import java.util.Date
>> import com.testmodel.Event
>>
>>
>> //declarations
>> declare Event
>> @role(event)
>> @timestamp( timestamp )
>> end
>>
>> declare LastEvent
>> event: Event
>> end
>>
>>
>> rule "init"
>> when
>> //once...
>> then
>> System.out.println("init");
>> LastEvent l = new LastEvent();
>> Event e = new Event();
>> e.timestamp = new Date();
>> e.value = 0;
>> l.event = e;
>> insert(l);
>> end
>>
>> rule "update LastEvent"
>> no-loop
>> salience 99
>> when
>> $event : Event()
>> $last : LastEvent()
>> then
>> System.out.println("update LastEvent");
>> retract ($last)
>> LastEvent l = new LastEvent();
>> l.event = $event;
>> insert(l);
>> end
>>
>>
>> rule "count old"
>> when
>> LastEvent($last : event)
>> $old : Event(this before [0 , 5s] $last) //<<<<<<<<<< THIS IS EVIL?!
>> then
>> System.out.println($old);
>> end
>>
>> My test code looks like this:
>>
>> Event event = new Event(new Date(), 1);
>> ksession.insert(event);
>> ksession.fireAllRules();
>>
>> //sleep 1+ sec
>> Thread.sleep(1001);
>>
>> Event event2 = new Event(new Date(), 2);
>> ksession.insert(event2);
>> ksession.fireAllRules();
>>
>>
>> And this is the Exception I get:
>>
>> Exception executing consequence for rule "init" in testEasierLife: [Error:
>> drools.insert(l): com.testmodel.Event cannot be cast to java.lang.Number]
>> [Near : {... System.out.println("init"); ....}]
>> ^
>> [Line: 1, Column: 1]
>> at
>> org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)
>> at
>> org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1297)
>> at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:1221)
>> at org.drools.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1456)
>> 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.Test.test(PeepholeTest.java:65)
>> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>> at
>> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
>> at
>> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
>> at java.lang.reflect.Method.invoke(Method.java:597)
>> at
>> org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
>> at
>> org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
>> at
>> org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
>> at
>> org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
>> at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
>> at
>> org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
>> at
>> org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
>> at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
>> at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
>> at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
>> at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
>> at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
>> at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
>> at
>> org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
>> at
>> org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
>> at
>> org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
>> at
>> org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
>> at
>> org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
>> at
>> org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
>> Caused by: [Error: drools.insert(l): com.testmodel.Event cannot be cast to
>> java.lang.Number]
>> [Near : {... System.out.println("init"); ....}]
>> ^
>> [Line: 1, Column: 1]
>> at
>> org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:416)
>> at
>> org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.optimizeAccessor(ReflectiveAccessorOptimizer.java:143)
>> at org.mvel2.ast.ASTNode.optimize(ASTNode.java:159)
>> at org.mvel2.ast.ASTNode.getReducedValueAccelerated(ASTNode.java:115)
>> at org.mvel2.MVELRuntime.execute(MVELRuntime.java:85)
>> at
>> org.mvel2.compiler.CompiledExpression.getDirectValue(CompiledExpression.java:123)
>> at
>> org.mvel2.compiler.CompiledExpression.getValue(CompiledExpression.java:119)
>> at
>> org.mvel2.compiler.CompiledExpression.getValue(CompiledExpression.java:113)
>> at org.mvel2.MVEL.executeExpression(MVEL.java:930)
>> at
>> org.drools.base.mvel.MVELConsequence.evaluate(MVELConsequence.java:104)
>> at
>> org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1287)
>> ... 29 more
>> Caused by: java.lang.reflect.InvocationTargetException
>> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>> at
>> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
>> at
>> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
>> at java.lang.reflect.Method.invoke(Method.java:597)
>> at
>> org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.getMethod(ReflectiveAccessorOptimizer.java:1104)
>> at
>> org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.getMethod(ReflectiveAccessorOptimizer.java:987)
>> at
>> org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:377)
>> ... 39 more
>> Caused by: java.lang.ClassCastException: com.testmodel.Event cannot be
>> cast to java.lang.Number
>> at
>> org.drools.base.evaluators.BeforeEvaluatorDefinition$BeforeEvaluator.evaluateCachedLeft(BeforeEvaluatorDefinition.java:337)
>> at
>> org.drools.rule.constraint.EvaluatorConstraint.isAllowedCachedLeft(EvaluatorConstraint.java:67)
>> at
>> org.drools.common.SingleBetaConstraints.isAllowedCachedLeft(SingleBetaConstraints.java:125)
>> at org.drools.reteoo.JoinNode.propagateFromLeft(JoinNode.java:105)
>> at org.drools.reteoo.JoinNode.assertLeftTuple(JoinNode.java:95)
>> at
>> org.drools.reteoo.SingleLeftTupleSinkAdapter.doPropagateAssertLeftTuple(SingleLeftTupleSinkAdapter.java:196)
>> at
>> org.drools.reteoo.SingleLeftTupleSinkAdapter.createAndPropagateAssertLeftTuple(SingleLeftTupleSinkAdapter.java:145)
>> at
>> org.drools.reteoo.LeftInputAdapterNode.assertObject(LeftInputAdapterNode.java:154)
>> at
>> org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateAssertObject(CompositeObjectSinkAdapter.java:497)
>> at
>> org.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject(CompositeObjectSinkAdapter.java:382)
>> at
>> org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:235)
>> at
>> org.drools.reteoo.EntryPointNode.assertObject(EntryPointNode.java:240)
>> at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:350)
>> at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:311)
>> at
>> org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:903)
>> at
>> org.drools.base.DefaultKnowledgeHelper.insert(DefaultKnowledgeHelper.java:192)
>> at
>> org.drools.base.DefaultKnowledgeHelper.insert(DefaultKnowledgeHelper.java:186)
>> ... 46 more
>>
>>
>>
>>
>
>
More information about the rules-users
mailing list