[rules-users] Drool Rule Error with "or not" condition

[Shah, Malay]

Thanks Mark. I removed the binding and the rule is compiled now, but while firing the rule over set of objects, I get a Null pointer exception.
Here is the updated Drool rule:

dialect "mvel"
rule "Legacy ETSDB Rule"
when
        EtsExecutionOrderHist_core0:EtsExecutionOrderHist_core(customerOrFirm != "0")
        EtsExecutionOrderXref_core00:EtsExecutionOrderXref_core
        (
            entityOID == EtsExecutionOrderHist_core0.entityOID,
            entityRID == EtsExecutionOrderHist_core0.entityRID,
            entityVID == EtsExecutionOrderHist_core0.entityVID,
            referenceID != "2" && referenceIDType == "orderSubCapacity"
        )
        or
        not(EtsExecutionOrderXref_core
                (
                    entityOID == EtsExecutionOrderHist_core0.entityOID,
                    entityRID == EtsExecutionOrderHist_core0.entityRID,
                    entityVID == EtsExecutionOrderHist_core0.entityVID,
                    referenceIDType == "orderSubCapacity"
                )
            )
then
    System.out.println("Rule fired");
end

and here is the stack trace:

Exception in thread "main" org.drools.runtime.rule.ConsequenceException: java.lang.NullPointerException
 at org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:23)
 at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:943)
 at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:885)
 at org.drools.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1086)
 at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:660)
 at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:637)
 at org.drools.reteoo.ReteooStatelessSession.execute(ReteooStatelessSession.java:203)
 at com.ms.ruleutils.RuleProcessor.process(RuleProcessor.java:142)
 at com.ms.ruleutils.RuleProcessor.process(RuleProcessor.java:73)
 at com.ms.ieddata.dataQuality.dqWithRR.DQCommandLineMain.performDQ(DQCommandLineMain.java:291)
 at com.ms.ieddata.dataQuality.dqWithRR.DQCommandLineMain.runEngine(DQCommandLineMain.java:196)
 at com.ms.ieddata.dataQuality.dqWithRR.DQCommandLineMain.main(DQCommandLineMain.java:170)
Caused by: java.lang.NullPointerException
 at org.drools.base.mvel.DroolsMVELFactory.getTupleObjectFor(DroolsMVELFactory.java:182)
 at org.drools.base.mvel.DroolsMVELFactory.setContext(DroolsMVELFactory.java:176)
 at org.drools.base.mvel.MVELConsequence.evaluate(MVELConsequence.java:57)
 at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:934)
 ... 10 more

After debugging through, DroolMVELFactory class object is looking for Declaration definition for "EtsExecutionOrderXref_core00", not finding it, and hence giving a null pointer exception. I am using Drools 5.0.1. Any idea about why this would happen? Does the rule seem right now?
Thanks

Malay Shah


________________________________
From: rules-users-bounces at lists.jboss.org [mailto:rules-users-bounces at lists.jboss.org] On Behalf Of Mark Proctor
Sent: Tuesday, December 01, 2009 6:56 PM
To: Rules Users List
Subject: Re: [rules-users] Drool Rule Error with "or not" condition

You are binding the result of the 'or' to EtsExecutionOrderXref_core00 as the second part is a 'not' which returns nothing, how would it be bound to?

Shah, Malay wrote:
Hi All,

I have the following drool rule that has "or not" under Entity Block. Basically, the rule tries to check if there either exists an entity object EtsExecutionOrderXref_core00 with the given conditions, or the entity does not exist at all with some other conditions.

dialect "mvel"
rule "Legacy ETSDB Rule"
when
EtsExecutionOrderHist_core0:EtsExecutionOrderHist_core(customerOrFirm != "0")
EtsExecutionOrderXref_core00:
(
 EtsExecutionOrderXref_core
 (
  entityOID == EtsExecutionOrderHist_core0.entityOID , entityRID == EtsExecutionOrderHist_core0.entityRID , entityVID == EtsExecutionOrderHist_core0.entityVID , referenceID != "2" && referenceIDType == "orderSubCapacity"
 )
 or not(EtsExecutionOrderXref_core
 (
  entityOID == EtsExecutionOrderHist_core0.entityOID , entityRID == EtsExecutionOrderHist_core0.entityRID , entityVID == EtsExecutionOrderHist_core0.entityVID , referenceIDType == "orderSubCapacity"
 ))
)
then
end

But, while compiling the rule, I am getting the following errors:

org.drools.compiler.DroolsParserException: [ERR 101] Line 22:16 no viable alternative at input 'entityOID' in rule "Legacy ETSDB Rule" in pattern not,

org.drools.compiler.DroolsParserException: [ERR 102] Line 22:68 mismatched input ',' expecting '(' in rule "Legacy ETSDB Rule" in pattern EtsExecutionOrderHist_core0.entityOID,

org.drools.compiler.DroolsParserException: [ERR 102] Line 22:122 mismatched input ',' expecting '(' in rule "Legacy ETSDB Rule" in pattern EtsExecutionOrderHist_core0.entityOID in pattern EtsExecutionOrderHist_core0.entityRID,

org.drools.compiler.DroolsParserException: [ERR 102] Line 22:176 mismatched input ',' expecting '(' in rule "Legacy ETSDB Rule" in pattern EtsExecutionOrderHist_core0.entityOID in pattern EtsExecutionOrderHist_core0.entityRID in pattern EtsExecutionOrderHist_core0.entityVID]

I think the rule is correct, but am not able to figure out these compilation errors. Could anybody please comment on why this would happen?

Thanks

Malay Shah
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