code: @Override
      public void observe(int age) throws InterruptedException {
          if (System.currentTimeMillis() >= _limit) {
              throw new InterruptedException("Time{" + System.currentTimeMillis() + "}HasPassed{" + _limit + '}');
          }
      }
docs: Checks the current system time against the time limit, throwing an InterruptedException if the time is up.