[jboss-user] [jBPM] - Re: How to Complete a WorkItem using REST API

[analamala]

analamala [http://community.jboss.org/people/analamala] created the discussion

"Re: How to Complete a WorkItem using REST API"

To view the discussion, visit: http://community.jboss.org/message/631358#631358

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Hello Chris,
Thanks a lot for your time. Let me step back and thank you sincerely for the information that you posted at  http://community.jboss.org/thread/166755?start=0&tstart=0 http://community.jboss.org/thread/166755?start=0&tstart=0. Really helped in many ways.

Coming back to this discussion, I made some progress on how to complete a workitem by extending the REST API. To answer your question, yes, the code that I modified, is running in the context of a jbpm engine. Here are my changes to "gwt-console-server\WEB-INF\classes\org\jboss\bpm\console\server\ProcessMgmtFacade.java"

@POST
    @Path("definition/{id}/ctr_component_complete")
    @Produces("application/json")
    public Response ctrComponentComplete(@PathParam("id") String definitionId,
            @FormParam("sessionID") String sessionID,
            @FormParam("workitemID") String workItemID) {
        try {
            EntityManagerFactory emf = Persistence
                    .createEntityManagerFactory("org.jbpm.persistence.jpa");
            Environment env = KnowledgeBaseFactory.newEnvironment();
            env.set(EnvironmentName.ENTITY_MANAGER_FACTORY, emf);
            env.set(EnvironmentName.TRANSACTION_MANAGER,
                    TransactionManagerServices.getTransactionManager());
            UserTransaction ut = (UserTransaction) new InitialContext()
                    .lookup("java:comp/UserTransaction");
            env.set(EnvironmentName.TRANSACTION, ut);
            StatefulKnowledgeSession ksession = JPAKnowledgeService
                    .loadStatefulKnowledgeSession(
                            new Integer(sessionID).intValue(),
                            readKnowledgeBase(), null, env);
            ksession.getWorkItemManager().completeWorkItem(
                    new Long(workItemID).longValue(), null);

            ksession.dispose();

            return createJsonResponse("SUCCESS");
        } catch (Throwable t) {
            throw new WebApplicationException(t, 500);
        }
    }


private KnowledgeBase readKnowledgeBase() throws Exception {
        KnowledgeBuilder kbuilder = KnowledgeBuilderFactory
                .newKnowledgeBuilder();
        kbuilder.add(ResourceFactory.newClassPathResource("CTRWorkflow.bpmn"),
                ResourceType.BPMN2);
        KnowledgeBase kbase = kbuilder.newKnowledgeBase();
        kbase.addKnowledgePackages(kbuilder.getKnowledgePackages());
        return kbase;
}

As you can see, I am creating a new KnowledgeBase and using the parameters, 'sessionID' and 'workitemID' to accomplish this. Everything seems to be working as per the process design. However, in the jbpm-console web application's 'Process Overview' tab, the process instance is still showing up as 'RUNNING', eventhough I can see from the logs that the process has reached the end state. To confirm that the state is not changing, I clicked on the 'Diagram' button to bring up the process image. The image is coming up but not updating with the latest state. 


I have a feeling that this issue may be related to creating a new KnowledgeBase rather than using the existing KnowledgeBase that JBPM engine and the jbpm-console web application share. To mitigate this problem, I tried to get a reference to the KnowledgeBase by trying several alternate approaches. But by these alternate approaches, I am not able to even complete the workitem. Here is one of the approaches that I tried.

private KnowledgeBase readKnowledgeBase() throws Exception {
        KnowledgeBase kbase = null;
        try {
            ResourceChangeScannerConfiguration sconf = ResourceFactory.getResourceChangeScannerService().newResourceChangeScannerConfiguration();
            sconf.setProperty( "drools.resource.scanner.interval", "10" );
            ResourceFactory.getResourceChangeScannerService().configure( sconf );
            ResourceFactory.getResourceChangeScannerService().start();
            ResourceFactory.getResourceChangeNotifierService().start();
            KnowledgeAgentConfiguration aconf = KnowledgeAgentFactory.newKnowledgeAgentConfiguration();
            aconf.setProperty("drools.agent.newInstance", "false");
            KnowledgeAgent kagent = KnowledgeAgentFactory.newKnowledgeAgent("Guvnor default", aconf);
            kagent.applyChangeSet(ResourceFactory.newClassPathResource("ChangeSet.xml"));
            kbase = kagent.getKnowledgeBase();
            for (org.drools.definition.process.Process process: kbase.getProcesses()) {
                log.debug("Loading process from Guvnor: " + process.getId());
            }
        } catch (Throwable t) {
            if (t instanceof RuntimeException
                    && "KnowledgeAgent exception while trying to deserialize".equals(t.getMessage())) {
                log.error("Could not connect to guvnor");
                if (t.getCause() != null) {
                    System.out.println(t.getCause().getMessage());
                }
            }
            log.error("Could not load processes from guvnor: " + t.getMessage());
            t.printStackTrace();
        }
        if (kbase == null) {
            System.out.println("kbase is NULL");
            kbase = KnowledgeBaseFactory.newKnowledgeBase();
        }
        return kbase;
    }

Here is my process image. Note that both the domain specific service tasks, 'Extraction' & 'Validation' operate in asynchronous mode, by EXCLUDING the "manager.completeWorkItem(workItem.getId(), null);" call.

 http://community.jboss.org/servlet/JiveServlet/showImage/2-631358-17153/CTRworkflow.png  http://community.jboss.org/servlet/JiveServlet/downloadImage/2-631358-17153/450-144/CTRworkflow.png 
I really apreciate your time on this and hope this discussion helps few more community members out there.

Thank you.
-Ajay
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