Re: [rules-users] Agenda events in a Stateless session

Hi, I guess the issue is that StatelessKnowledgeSession doesn't extend the WorkingMemory interface as David pointed out. So if you call event.getKnowledgeRuntime() you'll get *null* back.

Similar issue happens when you call drools.getKnowledgeRuntime() from within rule's consequence. However in this case it throws the following exception (running with snapshot from 07. 03. 2009): org.drools.runtime.rule.ConsequenceException: java.lang.ClassCastException: *org.drools.reteoo.**ReteooWorkingMemory cannot be cast to org.drools.reteoo.**ReteooStatefulSession* 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:1082) at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:682) at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:659) at org.drools.impl.StatelessKnowledgeSessionImpl.execute(StatelessKnowledgeSessionImpl.java:213) at com.sample.DroolsTest.main(DroolsTest.java:45) Caused by: java.lang.ClassCastException: org.drools.reteoo.ReteooWorkingMemory cannot be cast to org.drools.reteoo.ReteooStatefulSession at org.drools.base.DefaultKnowledgeHelper.getKnowledgeRuntime(DefaultKnowledgeHelper.java:222) at com.sample.Rule_Hello_World_0.consequence(Rule_Hello_World_0.java:7) at com.sample.Rule_Hello_World_0ConsequenceInvoker.evaluate(Rule_Hello_World_0ConsequenceInvoker.java:26) at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:934) ... 6 more for this rule: rule "Hello World" when Message( ) then System.out.println( drools.getKnowledgeRuntime() ); end Best Regards, Michal On Fri, Mar 6, 2009 at 6:45 AM, Mark Proctor <mproctor(a)codehaus.org <mailto:mproctor@codehaus.org>> wrote: David Boaz wrote: > Your answer refered to Statefull session. My question was regarding a > stateless session, that do not extend WorkingMemory. > you are using an event, that event exposes the knowledgeruntime in the event listener - stateless and stateful use the same event model and both expose the knowledgeruntime as a parameter. All events should extend KnowledgeRuntimeEvent which provides the method getKnowledgeRuntime. Mark > Currently, I did an ugly work-around. The Activation returns a > Collection<FactHandle>, and I noticed that in runtime, the FactHandle is > instanceof InternalFactHandle, that do have a getObject(). So, My code looks > like: > for(FactHandle handle:activation.getFactHandles()){ > assert(handle instanceof InternalFactHandle); > Object o=((InternalFactHandle)handle).getObject(); > ... > } > Im looking for the correct way to implement this functionality. > Thanks, David > > > Mark Proctor wrote: > >> David Boaz wrote: >> >>> Thanks Mark, >>> >>> The post bellow doesn't deal with the event listener registration. >>> Assuming >>> the registration was solved, now I have another issue. How to retrieve >>> the >>> Facts given Fact-handles? In a stateless session, I have no access to the >>> working memory. >>> >>> >> If you are using StatefulKnowledgeSession. Then the Activation has >> Collection< ? extends FactHandle> getFactHandles(); >> >> And the KnowledgeRuntime is always available, which extends the >> WorkingMemory. >> >> Mkar >> >>> David >>> >>> >>> Mark Proctor wrote: >>> >>> >>>> David Boaz wrote: >>>> >>>> >>>>> Hi all, >>>>> >>>>> Im trying to listen to the events fired during the evaluation of a >>>>> stateless >>>>> session. I implemented org.drools.event.rule.AgendaEventListener. The >>>>> events >>>>> fire as expected. From the event I can extract the Activation, the Rule >>>>> and >>>>> the list of FactHandles. Now, from each FactHandle I want to retrieve >>>>> the >>>>> associated fact (Object). For that, I need a WorkingMemory. But the WM >>>>> doesn't participate in the event signature. In addition, since Im using >>>>> a >>>>> stateless session, the working memory does not exist until I execute() >>>>> method. >>>>> >>>>> Can you please help? >>>>> >>>>> >>>>> >>>> The event listeners don't work in the last release, this is fixed in >>>> trunk, please give it a try in a snapshot: >>>> https://hudson.jboss.org/hudson/job/drools/lastSuccessfulBuild/artifact/t... >>>> >>>> >>>>> Thanks, David >>>>> >>>>> >>>>> >>>> _______________________________________________ >>>> rules-users mailing list >>>> rules-users(a)lists.jboss.org <mailto:rules-users@lists.jboss.org> >>>> https://lists.jboss.org/mailman/listinfo/rules-users >>>> >>>> >>>> >>>> >>> >>> >> _______________________________________________ >> rules-users mailing list >> rules-users(a)lists.jboss.org <mailto:rules-users@lists.jboss.org> >> https://lists.jboss.org/mailman/listinfo/rules-users >> >> >> > _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org <mailto:rules-users@lists.jboss.org> https://lists.jboss.org/mailman/listinfo/rules-users ------------------------------------------------------------------------ _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users