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 <[email protected]
<mailto:[email protected]>> 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
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