[rules-users] org.drools.RuntimeDroolsException when inserting into Knowledge Session

[Wolfgang Laun]

The global ao must be assigned to the ksession, from your Java code, by
calling
   ksession.setGlobal( "ao",  assertionObject )
before you do anything that triggers LHS evaluations. See Drools Expert,
section 4.5.2.

The WM and rule setup as you present it does not make sense (to me). If you
insert an AssertionObject as a WM fact, you shouldn't have it as a global.
If you want it as a fact, you'll need rules with patterns like
when
   AssertionObject(...)
And the same goes for BillingRecord

-W


2009/8/1 Abarna Ramachandran <rabarna at archstone.in>

> I am getting the following error when trying to insert my object into
> ksession. I have attached my rules and java object. Please help me in
> debugging why this is happening. I am using java 5 and drools 5.0
>
> thanks
>
> *error while inserting:*
>
> org.drools.RuntimeDroolsException:
> defaultpkg.Rule_CheckStationNumber_0Eval0Invoker at e4aea391 :
> java.lang.NullPointerException
>
> *rules.drl*
> import java.lang.*;
> import java.util.*;
> import ct.fw.rules.*;
> import ct.fw.utils.*;
> import ct.fw.rules.*;
> import ct.fw.logging.*;
> import ct.fw.pf.dbi.*;
> import ct.fw.pf.dao.*;
> import ct.fw.pf.seq.*;
> import ct.fw.pf.util.*;
> import ct.fw.pf.vo.*;
> import ct.fw.ex.*;
> import org.apache.commons.lang.*;
> import com.aa.gccp.domain.*;
>
>    global ct.fw.rules.AssertionObject ao
>    global ct.fw.logging.SmartLogger log
>
>     function BillingRecord getRecord(AssertionObject ao)
>         {
>             return (BillingRecord) ao.get(0);
>         }
>     function void debug(String msg,SmartLogger log)
>         {
>             log.debug(BusinessRulesValidator.class, msg);
>         }
>     function void error(String msg,SmartLogger log)
>         {
>             log.error(BusinessRulesValidator.class, msg);
>             System.out.println("Message from rules "+msg);
>         }
>
> rule CheckTrue
> when
>    eval(true)
> then
>     System.out.println("evaluating true");
> end
>
> rule CheckTrue2
> when
>    eval(true)
> then
>     error("evaluating from rules2",log);
> end
>
> rule CheckStationNumber
> when
>    eval(((getRecord(ao)).getStationNo()) == null)
> then
>     error("station number should not be null",log);
> end
>
> *part where i load the rules and insert the facts. There is no error when
> loading the rules.drl. That means no parsing errors. The error happens at
> ksessio.insert(assertionObject).*
>
> public void assertRulesObject(AssertionObject assertionObject) throws
> BusinessRuleException
>     {
>         long current = System.currentTimeMillis();
>         KnowledgeBase kbase = knowledgeBasesMap.get(rulesFileName);
>
>         if (kbase == null)
>         {
>             kbase = knowledgeBasesMap.get(rulesFileName + DRL);
>         }
>
>         if ((kbase == null) || ((current - lastRefreshedMilliseconds) >
> refreshTimeMilliseconds))
>         {
>             if (rulesFileName.toLowerCase().indexOf(DRL) == -1)
>             {
>                 kbase = load(rulesFileName + DRL);
>             }
>             else
>             {
>                 kbase = load(rulesFileName);
>             }
>
>             lastRefreshedMilliseconds = System.currentTimeMillis();
>         }
>         this.assertionObject = assertionObject;
>
>         List assertionobjectslist = new ArrayList();
> *// i am just doing this part just to make sure assertion object is not
> null and i will get some answer. this part runs fine.  *
>   if (assertionObject != null)
>         {
>             assertionobjectslist = assertionObject.getValidationObjects();
>             String StationNumber = ((BillingRecord)
> assertionObject.get(0)).getStationNo();
>             System.out.println("Station Number in assertion object is " +
> StationNumber);
>         }
>         else
>         {
>             System.out.println("Assertion Object is null");
>         }
>         System.out.println("The number of objects in assertionobject is " +
> assertionobjectslist.size());
>
>         try
>         {
>             StatefulKnowledgeSession ksession =
> kbase.newStatefulKnowledgeSession();
> *//the next line throws the exception*
>             ksession.insert(assertionObject);
>
>             ksession.fireAllRules();
>             ksession.dispose();
>
>         }
>         catch (RuntimeDroolsException e1)
>         {
>             throw new BusinessRuleException(e1.getMessage());
>         }
>
>         businessRulesErrors = assertionObject.getBusinessRulesErrors();
>
>         if (throwException)
>         {
>             if (!assertionObject.getBusinessRulesErrors().isEmpty())
>             {
>                 throw new BusinessRuleException(businessRulesErrors);
>             }
>         }
>     }
>
>
> Any help is appreciated. thanks
>
>
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