code: public void advanceClock(final int offset) {
      this.currentTime += offset;
      final Iterator<Alarm> iter = this.alarmList.iterator();
      while (iter.hasNext()) {
        final Alarm alarm = iter.next();
        if (alarm.getTimestamp() <= this.currentTime) {
          alarm.run();
          iter.remove();
        }
      }
    }
docs: Advances the clock by the offset amount.
  @param offset amount to advance clock