task.java

/*
 * When a Task is aborted, it should b aborted in the taskQueue and its state should be
 * persisted to taskStorage. There is also a start method with similar requirements.
 *
 * Below are different implementation alternatives for a REST method.
 */


// Alt. 1 -- Task knows about taskStorage and taskQueue:
taskStorage.getTask( id ).abort().save();

// ------------------------

// Alt. 2:
taskStorage.getTask( id ).abort();
taskStorage.save( t );
taskQueue.abort( e );

// ------------------------

// Alt. 3
taskStorage.abort( id );
taskQueue.abort( id );

// ------------------------

// Alt. 4 -- Task knows about taskQueue. A callback that updates taskStorage
// has been registered using Task.setOnAborted:
taskStorage.getTask( id ).abort();

// ------------------------

// Alt. 5 -- Similar to alt. 4, but Task doesn't know about taskQueue.
taskQueue.abort( id );

// ------------------------

// Alt. 6 -- Aspect Oriented Programming
// This annotation would only be used once in the codebase.
class TaskQueue {
  @PersistState
  void abort( Task t )
}