@Override
  public String toString() { 
    return appendTo(new StringBuilder(TASK)).toString();
  }
@Test
  public void testToString() {
    JobID jobId = new JobID("1234", 1);

    for (TaskType type : TaskType.values()) {
      TaskID taskId = new TaskID(jobId, type, 0);
      String str = String.format("task_1234_0001_%c_000000",
          TaskID.getRepresentingCharacter(type));

      assertEquals("The toString() method returned the wrong value",
          str, taskId.toString());
    }
  }