[jboss-jira] [JBoss JIRA] (DROOLS-163) NPE when updating a fact of a FromNode
Andreas Volz (JIRA)
jira-events at lists.jboss.org
Wed Jun 5 03:52:54 EDT 2013
Andreas Volz created DROOLS-163:
-----------------------------------
Summary: NPE when updating a fact of a FromNode
Key: DROOLS-163
URL: https://issues.jboss.org/browse/DROOLS-163
Project: Drools
Issue Type: Bug
Security Level: Public (Everyone can see)
Affects Versions: 6.0.0.Beta2, 5.5.0.Final
Environment: Windows7, JDK 1.6.26
Reporter: Andreas Volz
Assignee: Mark Proctor
A NullPointerException is thrown when updating a fact of a FromNode.
Here is the corresponding stack trace:
{code}
Exception executing consequence for rule "update_TestObjects_from_TestObjectContainer" in de.avo: java.lang.NullPointerException
at org.drools.core.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)
at org.drools.core.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1424)
at org.drools.core.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:1343)
at org.drools.core.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1561)
at org.drools.core.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:637)
at org.drools.core.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:601)
at de.avo.Builder.fireAllRules(Builder.java:47)
at de.avo.NPETest.testWrongFiringOrder(NPETest.java:37)
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.internal.runners.TestMethod.invoke(TestMethod.java:59)
at org.junit.internal.runners.MethodRoadie.runTestMethod(MethodRoadie.java:98)
at org.junit.internal.runners.MethodRoadie$2.run(MethodRoadie.java:79)
at org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters(MethodRoadie.java:87)
at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:77)
at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:42)
at org.junit.internal.runners.JUnit4ClassRunner.invokeTestMethod(JUnit4ClassRunner.java:88)
at org.junit.internal.runners.JUnit4ClassRunner.runMethods(JUnit4ClassRunner.java:51)
at org.junit.internal.runners.JUnit4ClassRunner$1.run(JUnit4ClassRunner.java:44)
at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:27)
at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:37)
at org.junit.internal.runners.JUnit4ClassRunner.run(JUnit4ClassRunner.java:42)
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: java.lang.NullPointerException
at org.drools.core.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:374)
at org.drools.core.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:439)
at org.drools.core.base.ModifyInterceptor.doAfter(ModifyInterceptor.java:79)
at org.mvel2.ast.InterceptorWrapper.getReducedValueAccelerated(InterceptorWrapper.java:40)
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.core.base.mvel.MVELConsequence.evaluate(MVELConsequence.java:100)
at org.drools.core.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1414)
... 28 more
{code}
By debugging the Drools code (version 6.0.0.Beta2) I've found out that in the class FromNode FactHandles are created; e.g. in the method createRightTuple:
{code:title=FromNode#createRightTuple}
...
if( _handle != null ) {
// create a handle with the given id
handle = workingMemory.getFactHandleFactory().newFactHandle( _handle.getId(),
object,
_handle.getRecency(),
null, // set this to null, otherwise it uses the driver fact's entrypoint
workingMemory,
null );
} else {
handle = workingMemory.getFactHandleFactory().newFactHandle( object,
null, // set this to null, otherwise it uses the driver fact's entrypoint
workingMemory,
null );
}
...
{code}
As one can see in the code snippet above, the EntryPoint of the FactHandle is set to null. The newly created FactHandles are stored in the field {{identityMap}} of a knowledge helper (its type is DefaultKnowledgeHelper).
When the fact that corresponds to the newly created FactHandle has to be updated, the method {{update(FactHandle handle, long mask, Class<?> modifiedClass)}} is called. In this method the EntryPoint of the FactHandle is used to issue the update. Since this EntryPoint has been set to null by the class FromNode, a NPE is thrown. Here is the code snippet where the NPE is thrown:
{code:title=DefaultKnowledgeHelper}
public void update(final FactHandle handle, long mask, Class<?> modifiedClass) {
InternalFactHandle h = (InternalFactHandle) handle;
((InternalWorkingMemoryEntryPoint) h.getEntryPoint()).update( h,
((InternalFactHandle)handle).getObject(),
mask,
modifiedClass,
this.activation );
...
{code}
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