android/guava/src/com/google/common/util/concurrent/Monitor.java
@GuardedBy("lock")
  private boolean awaitNanos(Guard guard, long nanos, boolean signalBeforeWaiting)
      throws InterruptedException {
    boolean firstTime = true;
    try {
      do {
        if (nanos <= 0L) {
          return false;
        }
        if (firstTime) {
          if (signalBeforeWaiting) {
            signalNextWaiter();
          }
          beginWaitingFor(guard);
          firstTime = false;
        }
        nanos = guard.condition.awaitNanos(nanos);
      } while (!guard.isSatisfied());
      return true;
    } finally {
      if (!firstTime) {
        endWaitingFor(guard);
      }
    }
  }
@GuardedBy("lock")
  private boolean awaitNanos(Guard guard, long nanos, boolean signalBeforeWaiting)
      throws InterruptedException {
    boolean firstTime = true;
    try {
      do {
        if (nanos <= 0L) {
          return false;
        }
        if (firstTime) {
          if (signalBeforeWaiting) {
            signalNextWaiter();
          }
          beginWaitingFor(guard);
          firstTime = false;
        }
        nanos = guard.condition.awaitNanos(nanos);
      } while (!guard.isSatisfied());
      return true;
    } finally {
      if (!firstTime) {
        endWaitingFor(guard);
      }
    }
  }
Caller should check before calling that guard is not satisfied.