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

Michal Bali wrote: > 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. when in an event or in a consequence, whether using a stateless or stateful session it should return a knowledgeruntime instance - if it's not, it's a bug. I'll look into it.

> > 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 > ------------------------------------------------------------------------ _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users