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@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/trunk/target/
    
        
Thanks, David
  
      
          
_______________________________________________
rules-users mailing list
rules-users@lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users


    
        
  
      
_______________________________________________
rules-users mailing list
rules-users@lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users


_______________________________________________
rules-users mailing list
rules-users@lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users



_______________________________________________
rules-users mailing list
rules-users@lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users