Kris
Quoting PremKumar s <
premkumar.sivanandan@gmail.com>:
> Kris,
>
> I am new to drools flow am not aware of other better ways to
> pass
> ProcessInstance to drools rule (DRL) When conditions. Based on few
> examples in the forum and sample testing code with out inserting
> processInstance to working memory rule constraints not able get to
> process
> instance in drools rule drl file.
>
> If would be great if could suggest better approach to pass the
> process
> instance to drools rule (DRL) conditions. I with try that out and
> update
> you.
>
> Thanks
> Prem
>
> On Fri, Oct 9, 2009 at 7:12 AM, Kris Verlaenen <
>
kris.verlaenen@cs.kuleuven.be> wrote:
>
> > You can register a custom strategy like this:
> >
> > Environment env = KnowledgeBaseFactory.newEnvironment();
> > env.set(EnvironmentName.ENTITY_MANAGER_FACTORY, emf);
> > env.set(EnvironmentName.TRANSACTION_MANAGER,
> > TransactionManagerServices.getTransactionManager());
> > ObjectMarshallingStrategy[] objectMarshalingStrategies = new
> > ObjectMarshallingStrategy[] {
> > new ProcessInstanceMarshallingStrategy(env)
> > };
> > env.set(EnvironmentName.OBJECT_MARSHALLING_STRATEGIES,
> > objectMarshalingStrategies);
> > StatefulKnowledgeSession ksession =
> > JPAKnowledgeService.newStatefulKnowledgeSession(kbase, null, env);
> >
> > ... and then define the strategy as ...
> >
> > private static class ProcessInstanceMarshallingStrategy implements
> > ObjectMarshallingStrategy {
> > private Environment environment;
> > public ProcessInstanceMarshallingStrategy(Environment environment)
> {
> > this.environment = environment;
> > }
> > public boolean accept(Object o) {
> > return o instanceof ProcessInstance;
> > }
> > public Object read(ObjectInputStream ois) throws IOException,
> > ClassNotFoundException {
> > long id = ois.readLong();
> > return ((ProcessRuntime)
> > environment.get("ksession")).getProcessInstance(id);
> > }
> > public void write(ObjectOutputStream oos, Object o) throws
> IOException {
> > oos.writeLong(((ProcessInstance) o).getId());
> > }
> > }
> >
> > Note that this strategy only works for active process instances (so
> you
> > need to make sure they are removed from the working memory before
> ending
> > the process instance, for example by using an on-entry/exit action.
> I
> > think we will probably build in this strategy by default in the
> future.
> >
> > Could you clarify why you need the processInstance in the working
> > memory? As there might be an easier alternative?
> >
> > Kris
> >
> >
> > Quoting PremKumar s <
premkumar.sivanandan@gmail.com>:
> >
> > > Thanks Kris for your input. It would be great if you could share
> us
> > > on
> > > sample code snippet how to acheive this
> ObjectMarshallingStrategy
> > > for
> > > ProcessInstances .
> > >
> > > Also confirm us by using this approach the process is avialable
> for
> > > drools
> > > rule constraints to take decisions.
> > >
> > > Thanks
> > > Prem
> > >
> > > On Thu, Oct 8, 2009 at 4:07 PM, Kris Verlaenen <
> > >
kris.verlaenen@cs.kuleuven.be> wrote:
> > >
> > > > This is indeed a special case. Process instances are already
> > > stored as
> > > > part of the session runtime state, so no need to store them
> again
> > > as
> > > > part of the working memory. You need to register a custom
> > > > ObjectMarshallingStrategy for ProcessInstances in the working
> > > memory
> > > > that simply retrieves them from the session state.
> > > >
> > > > Kris
> > > >
> > > > Quoting PremKumar s <
premkumar.sivanandan@gmail.com>:
> > > >
> > > > > Hi,
> > > > >
> > > > >
> > > > >
> > > > > I am evaluating the drools expert with drool flow
> using
> > > > > TimeManagement
> > > > > System. I am inserting the process instance into working
> memory
> > > of
> > > > > drools
> > > > > [session.insert(workflowProcessInstance)] So that the rules
> can
> > > use
> > > > > the
> > > > > process instance as part of Rule constraints to enable the
> rules
> > > to
> > > > > make
> > > > > more sophisticated decisions based on the state of the
> current
> > > > > process
> > > > > instance.
> > > > >
> > > > >
> > > > >
> > > > > Rule snippet
> > > > >
> > > > >
> > > > >
> > > > > rule "Submit Time" ruleflow-group "Submit Time"
> > > > > dialect "java"
> > > > > when
> > > > >
> > > > > processInstance:WorkflowProcessInstance()
> > > > >
> > > > > tkRequest:TKRequest ()
> > > > > tkRequestDAO:TKRequestDAO()
> > > > > then
> > > > >
> > > > > // check the current processInstance
> state
> > > as
> > > > > Active
> > > > > then do that
> > > > >
> > > > > //Do custom operation, status change,
> > > > > persistence
> > > > > update
> > > > >
> > > > > end
> > > > >
> > > > >
> > > > >
> > > > > The approach is works fine with using
> > > > > KnowledgeBuilder.newStatefulKnowledgeSession() that is no
> > > > > persistence. But
> > > > > once i have enabled the Persistence using
> > > > > JPAKnowledgeService.newStatefulKnowledgeSession(know, null,
> > > > > getEnvironment()) it throws stack over flow error due the
> > > > > workflowProcessInstance is not serialized while trying to
> persist
> > > the
> > > > > newly
> > > > > added workflowProcessInstance to working memory.
> > > > >
> > > > >
> > > > >
> > > > > Once i have commented the
> > > > > session.insert(workflowProcessInstance)
> > > > > the stack overflow error is gone but none of my rules are
> not
> > > > > executed.
> > > > >
> > > > >
> > > > >
> > > > > Can some one provide guidance on how to pass this
> > > > > workflowProcessInstance to
> > > > > rule constriant with persistence JPAKnowledgeSession
> enabled.
> > > > >
> > > > >
> > > > >
> > > > > Thanks
> > > > >
> > > > > Prem
> > > > >
> > > >
> > > >
> > > >
> > > >
> > > > Disclaimer:
http://www.kuleuven.be/cwis/email_disclaimer.htm
> > > >
> > >
> >
> >
> >
> >
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> >
>
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