Hi Davide,
I've got a null pointer exception with defeasible. My test case is:
package com.sample
declare Fact
fact: String @key
end
rule init
when
then
System.out.println("inserting initial facts");
insert( new Fact( "one" ) );
insert( new Fact( "two" ) );
insert( new Fact( "two" ) );
end
rule rule1
@Defeasible
enabled true
when
Fact( "one"; )
then
System.out.println("one causes wibble");
insertLogical( new Fact( "wibble") );
end
rule rule2
@Defeasible
when
Fact( "two"; )
then
System.out.println("two causes wibble");
insertLogical( new Fact( "wibble") );
end
rule rule3
@Defeater
@Defeats( "rule2" )
when
Fact( "two"; )
then
System.out.println("two negates wibble");
insertLogical( new Fact( "wibble"), "neg" );
end
The output I get is
inserting initial facts
one causes wibble
two causes wibble
two causes wibble
two negates wibble
two negates wibble
Exception executing consequence for rule "rule3" in com.sample:
java.lang.NullPointerException
at
org.drools.core.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)
at
org.drools.core.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1057)
at org.drools.core.phreak.RuleExecutor.fire(RuleExecutor.java:152)
at
org.drools.core.phreak.RuleExecutor.evaluateNetworkAndFire(RuleExecutor.java:94)
at
org.drools.core.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:964)
at
org.drools.core.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1234)
at
org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1239)
at
org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1212)
at com.sample.DroolsTest.main(DroolsTest.java:21)
Caused by: java.lang.NullPointerException
at
org.drools.core.beliefsystem.defeasible.DefeasibleBeliefSet.removeUndefeated(DefeasibleBeliefSet.java:295)
at
org.drools.core.beliefsystem.defeasible.DefeasibleBeliefSet.add(DefeasibleBeliefSet.java:126)
at
org.drools.core.beliefsystem.jtms.JTMSBeliefSystem.insert(JTMSBeliefSystem.java:52)
at
org.drools.core.beliefsystem.defeasible.DefeasibleBeliefSystem.insert(DefeasibleBeliefSystem.java:45)
at
org.drools.core.common.TruthMaintenanceSystem.addLogicalDependency(TruthMaintenanceSystem.java:136)
at
org.drools.core.common.TruthMaintenanceSystem.addLogicalDependency(TruthMaintenanceSystem.java:107)
at
org.drools.core.common.NamedEntryPoint.insert(NamedEntryPoint.java:234)
at
org.drools.core.impl.StatefulKnowledgeSessionImpl.insert(StatefulKnowledgeSessionImpl.java:1430)
at
org.drools.core.base.DefaultKnowledgeHelper.insertLogical(DefaultKnowledgeHelper.java:275)
at
org.drools.core.base.DefaultKnowledgeHelper.insertLogical(DefaultKnowledgeHelper.java:247)
at
com.sample.Rule_rule32132126114.defaultConsequence(Rule_rule32132126114.java:8)
at
com.sample.Rule_rule32132126114DefaultConsequenceInvokerGenerated.evaluate(Unknown
Source)
at
com.sample.Rule_rule32132126114DefaultConsequenceInvoker.evaluate(Unknown
Source)
at
org.drools.core.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1046)
... 7 more
I believe I am using snapshot 6.1.0.201407170510 but I suspect the
precise version doesn't matter too much.
In the above example, if you disable rule1 then the NPE doesn't happen.
Only doing one "two" fact insertion in the init rule likewise means the
NPE doesn't happen. I think the issue is something like rule3 does more
than one defeat on rule2's scoring on "wibble" fact, but rule1 still has
a say in the continuing existence of the "wibble" fact.
Should I get a Jira log in and enter these well qualified bugs directly?
Regards,
Borris
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