[jboss-user] [jBPM] - Re: Getting process instance variables

Sandra Renaud do-not-reply at jboss.com
Fri Mar 22 06:07:05 EDT 2013

Sandra Renaud [https://community.jboss.org/people/joploya] created the discussion

"Re: Getting process instance variables"

To view the discussion, visit: https://community.jboss.org/message/804237#804237


I try this solution to retrieve processInstance varaibles but I got a NullPointerException.

Before I tried this solution :  https://community.jboss.org/message/798123#798123 https://community.jboss.org/message/798123 without success.

Eric how can you do to have a not null processInstance please?

Here my code :
           * This method allow to access object store in
           * process instance variables
           * @return an object link to the processInstance
          public Object getProcessVariable(Long processInstanceId, Long taskId, String key){
                    final Long piId = processInstanceId;
                    Object retObj = null;
                    WorkflowProcessInstance wpi = (WorkflowProcessInstance)kSession.getProcessInstance(processInstanceId);
                    if((wpi == null) || (wpi.getVariable(key) == null)){

                              //method1 : retrieve content map variables
                              Task task = getTaskService().getTask(taskId);
                              TaskData tData = task.getTaskData();
                              Long docContentId = tData.getDocumentContentId();
                              System.out.println("process instance is null, doc contentId = "+docContentId);
                              Content content = getTaskService().getContent(docContentId);
                              Map<?, ?> variables = ((Map<?, ?>) ContentMarshallerHelper.unmarshall(content.getContent(), null));

                              //display keys
                              System.out.println("content map keys :");
                              for(Object o : variables.keySet()){
                              System.out.println("and key search is "+key);
                              content map keys :

                              key search is formId
                              retObj = variables.get(key);

                              //method 2 : retrieve the the variable Scope
                              Map<String, Object> variables2 = kSession.execute(new GenericCommand<Map<String, Object>>(){

                                        public Map<String, Object> execute(Context context) {
                                                  StatefulKnowledgeSession ksession = ((KnowledgeCommandContext) context).getStatefulKnowledgesession();
                                                  ProcessInstanceImpl processInstance = (ProcessInstanceImpl) ksession.getProcessInstance(piId);
                                                  VariableScopeInstance variableScope = (VariableScopeInstance) processInstance.getContextInstance(VariableScope.VARIABLE_SCOPE); // ==> NullPointerException
                                                  Map<String, Object> variables = variableScope.getVariables();
                                                  return variables;

                              //display keys
                              System.out.println("variables keys :");
                              for(Object o : variables2.keySet()){
                              System.out.println("key search is "+key);

                              retObj = variables2.get(key);
                              retObj = wpi.getVariable(key);
                    return retObj;

Thanks and Best Regards.

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