How to get the activity instance id and process id

Question

Dear All,
For my case, my boss require the workflow program processor can be runtime assigned . After research, I found the coding example like below:
// dynamically assign a user to a role
rtm.addRuntimeDefinedUserToRole(
                  // process instance
                  prInstance,
                  // role name
                  "Processor",
                  // user that is assigned (IUser)
                  user,
                  // user context (IGPUserContext)
                  userContext);
// dynamically change the user assigned to a role for a particular task
String prInstanceID = prInstance.getID();
rtm.changeTaskProcessor(
                  // process instance ID
                  prInstanceID,
                  // activity instance ID
                  activityInstanceID,
                  // current user (IGPUserContext)
                  currentProcessorContext,
                  // new user (IGPUserContext)
                  newProcessorContext);
But I don't know how to get the process instance ID and activity instance ID before I can apply this api in my webdynpro application.
Any gentllement can give me an idea.
Thank you.
Regards
Eric

Answer 1

process =  GPProcessFactory.getDesigntimeManager().getActiveTemplate(
                              // by specifying its ID "CCD2C3F1BED111DD9DFA005056A9416C",/
                                             /* and the user accessing it */ userContext);
     //          retrieve the Runtime Manager
     IGPRuntimeManager rtm = GPProcessFactory.getRuntimeManager();
     // create an empty role assignment list
     IGPProcessRoleInstanceList roles = rtm.createProcessRoleInstanceList();
     //Initialising the input params
     IGPStructure params =GPStructureFactory.getStructure(process.getInputParameters());
     params.setAttributeValue("Name",value);
     //Starting the process
     IGPProcessInstance prInstance = rtm.startProcess(process,"Process Name","Process name",user,roles,params,user);