topic Re: What is the process variable scope for? in Alfresco Archive

What is the process variable scope for?

goto_tony — Sun, 16 Sep 2012 02:07:35 GMT

I am using the activiti REST, before my process instance was initiated, I have to set values for the variables. And in next step, I use a user to login and check out his/her task, before "complete" command is fired, I have to set the previous variable value again,otherwise I can't retrieve the varia

Re: What is the process variable scope for?

jbarrez — Mon, 17 Sep 2012 15:03:29 GMT

How do you set your process variables, ie which method do you use?
variables are normally process-scope, and you have to take care to make them task-scoped. So it should work as you describe.

Re: What is the process variable scope for?

goto_tony — Tue, 18 Sep 2012 01:00:07 GMT

hi,
I just use REST api to perform task operations.

http://activiti.org/userguide/index.html#N12B83
Performs an operation (claim or complete) on a task. For the "complete" operation additional variables (from a form) may be passed in the body. To read more about additional variables from forms, visit the Start Process Instance section

Request: PUT /task/{taskId}/[claim|complete]
{}
API: ProcessEngines.getProcessEngine(configuredProcessEngineName).getTaskService().xxx(taskId …)
Response:
{
"success": true
}

If I didn't set variables value by JSON input, the following task will discard the original variable's value. So it seems strange for me according to your description.

Re: What is the process variable scope for?

jbarrez — Tue, 18 Sep 2012 09:11:30 GMT

I checked the code, and as far as I can see, all the input variables are stored as process variables, as the rest layer is just calling the complete() method on the taskService


@Put
  public ObjectNode executeTaskOperation(Representation entity) {
    if(authenticate() == false) return null;
    
    String taskId = (String) getRequest().getAttributes().get("taskId");
    String operation = (String) getRequest().getAttributes().get("operation");
    try {
      String startParams = entity.getText();
      JsonNode startJSON = new ObjectMapper().readTree(startParams);
      Iterator<String> itName = startJSON.getFieldNames();
      Map<String, Object> variables = new HashMap<String, Object>();
      while(itName.hasNext()) {
        String name = itName.next();
        JsonNode valueNode = startJSON.path(name);
        if (valueNode.isBoolean()) {
          variables.put(name, valueNode.getBooleanValue());
        } else if (valueNode.isLong()) {
          variables.put(name, valueNode.getLongValue());
        } else if (valueNode.isDouble()) {
          variables.put(name, valueNode.getDoubleValue());
        } else if (valueNode.isTextual()) {
          variables.put(name, valueNode.getTextValue());
        } else if("true".equals(valueNode.getTextValue()) || "false".equals(valueNode.getTextValue())) {
          variables.put(name, Boolean.valueOf(valueNode.getTextValue()));
        } else {
          variables.put(name, valueNode.getValueAsText());
        }
      }
      
      if ("claim".equals(operation)) {
        ActivitiUtil.getTaskService().claim(taskId, loggedInUser);
      } else if ("complete".equals(operation)) {
        variables.remove("taskId");
        [b]ActivitiUtil.getTaskService().complete(taskId, variables);[/b]
      } else {
        throw new ActivitiException("'" + operation + "' is not a valid operation");
      }
      
    } catch(Exception e) {
      throw new ActivitiException("Did not receive the operation parameters", e);
    }
    
    ObjectNode successNode = new ObjectMapper().createObjectNode();
    successNode.put("success", true);
    return successNode;
  }
}

If you follow that call, you'll see it ends up calling (in the CompleteTaskCmd class)


    if (variables!=null) {
      task.setExecutionVariables(variables);
    }
    
    completeTask(task);