[rules-users] Issue with literals in Drools Verifier 5.1.1

Nathan Bell Nathan.Bell at pharmacyonesource.com
Wed Nov 10 15:45:05 EST 2010


Using org.drools.verifier found in "drools-verifier-5.1.1.jar" I get an
org.drools.RuntimeDroolsException if a pattern in a rule LHS contains a
comparison to a literal value using the equals operator.

 

Please consider the following rule I created solely for the purposes of
isolating this issue.

 

package com.simple.test.rule

 

import com.p1s.mps.rulevalidator.TestFact;

 

rule "TestRule"

when

      $fact : TestFact(value == 1)

then

      System.out.println($fact.getValue());

end

 

 

The following class definition for the TestFact.

 

package com.p1s.mps.rulevalidator;

 

public class TestFact 

{

      private int value;

 

      public TestFact(int value) {

            this.value = value;

      }

      

      public int getValue() {

            return value;

      }

 

      public void setValue(int value) {

            this.value = value;

      }

 

      @Override

      public int hashCode() {

            final int prime = 31;

            int result = 1;

            result = prime * result + value;

            return result;

      }

 

      @Override

      public boolean equals(Object obj) {

            if (this == obj)

                  return true;

            if (obj == null)

                  return false;

            if (getClass() != obj.getClass())

                  return false;

            TestFact other = (TestFact) obj;

            if (value != other.value)

                  return false;

            return true;

      }     

}

 

The following unit test which attempts to use Verifier.

 

      @Test

      public final void testVerifierOnLiteral()

      {

            VerifierBuilder verBuilder  =
VerifierBuilderFactory.newVerifierBuilder();

        Verifier ver = verBuilder.newVerifier();

        String ruleText = getRuleFromResource(TEST_RULE);

        ver.addResourcesToVerify( ResourceFactory.newReaderResource( 

                  new StringReader( ruleText ) ), ResourceType.DRL );

        

        Assert.assertTrue(ver.fireAnalysis());       

      }

 

 

Running the test with JUnit produces the following exception.

java.lang.RuntimeException: org.drools.RuntimeDroolsException: Exception
executing ReturnValue constraint
org.drools.rule.ReturnValueRestriction at 589f81 : [Error: cannot convert
<1> to a numeric type: class java.lang.Integer [0]]

[Near : {... Unknown ....}]

             ^

[Line: 1, Column: 0]

                at
org.drools.verifier.builder.VerifierImpl.analyse(VerifierImpl.java:148)

                at
org.drools.verifier.builder.VerifierImpl.fireAnalysis(VerifierImpl.java:
117)

                at
com.p1s.mps.rulevalidator.NumericConversionTest.testVerifierOnLiteral(Nu
mericConversionTest.java:64)

                at sun.reflect.NativeMethodAccessorImpl.invoke0(Native
Method)

                at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown
Source)

                at
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

                at java.lang.reflect.Method.invoke(Unknown Source)

                at
org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMet
hod.java:44)

                at
org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallab
le.java:15)

                at
org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMetho
d.java:41)

                at
org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod
.java:20)

                at
org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.jav
a:28)

                at
org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:
31)

                at
org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner
.java:73)

                at
org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner
.java:46)

                at
org.junit.runners.ParentRunner.runChildren(ParentRunner.java:180)

                at
org.junit.runners.ParentRunner.access$000(ParentRunner.java:41)

                at
org.junit.runners.ParentRunner$1.evaluate(ParentRunner.java:173)

                at
org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.jav
a:28)

                at
org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:
31)

                at
org.junit.runners.ParentRunner.run(ParentRunner.java:220)

                at
org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4Tes
tReference.java:46)

                at
org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.ja
va:38)

                at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTe
stRunner.java:467)

                at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTe
stRunner.java:683)

                at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRun
ner.java:390)

                at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRu
nner.java:197)

Caused by: org.drools.RuntimeDroolsException: Exception executing
ReturnValue constraint org.drools.rule.ReturnValueRestriction at 589f81 :
[Error: cannot convert <1> to a numeric type: class java.lang.Integer
[0]]

[Near : {... Unknown ....}]

             ^

[Line: 1, Column: 0]

                at
org.drools.rule.ReturnValueConstraint.isAllowedCachedRight(ReturnValueCo
nstraint.java:168)

                at
org.drools.common.TripleBetaConstraints.isAllowedCachedRight(TripleBetaC
onstraints.java:211)

                at
org.drools.reteoo.NotNode.assertObject(NotNode.java:140)

                at
org.drools.reteoo.SingleObjectSinkAdapter.propagateAssertObject(SingleOb
jectSinkAdapter.java:59)

                at
org.drools.reteoo.AlphaNode.assertObject(AlphaNode.java:145)

                at
org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateAssertObject(Com
positeObjectSinkAdapter.java:450)

                at
org.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject(Compo
siteObjectSinkAdapter.java:378)

                at
org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:190)

                at
org.drools.reteoo.EntryPointNode.assertObject(EntryPointNode.java:145)

                at
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.jav
a:1174)

                at
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.jav
a:1123)

                at
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.jav
a:917)

                at
org.drools.impl.StatefulKnowledgeSessionImpl.insert(StatefulKnowledgeSes
sionImpl.java:251)

                at
org.drools.verifier.builder.VerifierImpl.analyse(VerifierImpl.java:136)

                ... 26 more

Caused by: org.drools.RuntimeDroolsException: [Error: cannot convert <1>
to a numeric type: class java.lang.Integer [0]]

[Near : {... Unknown ....}]

             ^

[Line: 1, Column: 0]

                at
org.drools.rule.ReturnValueRestriction.isAllowed(ReturnValueRestriction.
java:236)

                at
org.drools.rule.ReturnValueConstraint.isAllowedCachedRight(ReturnValueCo
nstraint.java:162)

                ... 39 more

Caused by: [Error: cannot convert <1> to a numeric type: class
java.lang.Integer [0]]

[Near : {... Unknown ....}]

             ^

[Line: 1, Column: 0]

                at
org.mvel2.math.MathProcessor.getInternalNumberFromType(MathProcessor.jav
a:577)

                at
org.mvel2.math.MathProcessor._doOperations(MathProcessor.java:155)

                at
org.mvel2.math.MathProcessor.doOperations(MathProcessor.java:79)

                at
org.mvel2.ast.BinaryOperation.getReducedValueAccelerated(BinaryOperation
.java:102)

                at org.mvel2.MVELRuntime.execute(MVELRuntime.java:85)

                at
org.mvel2.compiler.CompiledExpression.getValue(CompiledExpression.java:1
04)

                at org.mvel2.MVEL.executeExpression(MVEL.java:978)

                at
org.drools.base.mvel.MVELReturnValueExpression.evaluate(MVELReturnValueE
xpression.java:92)

                at
org.drools.rule.ReturnValueRestriction.isAllowed(ReturnValueRestriction.
java:226)

                ... 40 more

 

 

However, if I use the following version of the same rule where I have
added parentheses it works.

 

package com.simple.test.rule

 

import com.p1s.mps.rulevalidator.TestFact;

 

rule "TestRule"

when

      $fact : TestFact(value == (1))

then

      System.out.println($fact.getValue());

end

 

 

Note that both versions of the DRL file compile, run, and produce the
correct results.

 

Thank You,

Nathan Bell

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