public void rotateF() {
   try {
     queue.rotateF();
   } catch (EmptyQueueException e) {
     throw new EmptyClockException(e.getMessage());
   }
 }
 public S value() {
   try {
     return queue.value();
   } catch (EmptyQueueException e) {
     throw new EmptyClockException(e.getMessage());
   }
 }