Flush variables set through BusinessProcess

Question

When I set a process variable through org.camunda.bpm.engine.cdi.BusinessProcess.setVariable() it seems the value is not automatically flushed.

Is there a way to flush the variables without completing the current user task? I thought BusinessProcess.signalExecution() would be the solution but it seems to complete the current task just as BusinessProcess.completeTask() does.

What exactly is the difference between signalExecution and completeTask?

Answer 1

Variables are cached in the Request or Conversation until the unit of work is ended, for example by calling completeTask(). There is currently no out-of-the-box solution for manually flushing the cached variables. You could work around this by writing a Cdi Bean which injects the ContextAssociationManager and performs the flush:

@Inject
private ContextAssociationManager contextAssociationManager;

@Inject 
private TaskService taskService;

public void flushCachedVariables() {
  String taskId = contextAssociationManager.getTask().getId();
  taskService.setVariables(taskId, contextAssociationManager.getCachedVariables());
}

The difference between signalExecution and completeTask is as follows:

• completeTask: will complete the currently associated task using the TaskService
• signalExecution: is more abstract: it sends a signal to the currently associated execution to continue execution. In this case the effect is the same: the task is completed and execution continue. But signalExecution will also work in situations where there is no Human Task involved (ie. a ReceiveTask).