public RunnableScheduledFuture<?> take() throws InterruptedException {
final ReentrantLock lock = this.lock;
lock.lockInterruptibly();
try {
for (; ; ) {
RunnableScheduledFuture<?> first = queue[0];
if (first == null) available.await();
else {
long delay = first.getDelay(NANOSECONDS);
if (delay <= 0) return finishPoll(first);
else if (leader != null) available.await();
else {
Thread thisThread = Thread.currentThread();
leader = thisThread;
try {
available.awaitNanos(delay);
} finally {
if (leader == thisThread) leader = null;
}
}
}
}
} finally {
if (leader == null && queue[0] != null) available.signal();
lock.unlock();
}
}
public RunnableScheduledFuture<?> poll(long timeout, TimeUnit unit)
throws InterruptedException {
long nanos = unit.toNanos(timeout);
final ReentrantLock lock = this.lock;
lock.lockInterruptibly();
try {
for (; ; ) {
RunnableScheduledFuture<?> first = queue[0];
if (first == null) {
if (nanos <= 0) return null;
else nanos = available.awaitNanos(nanos);
} else {
long delay = first.getDelay(NANOSECONDS);
if (delay <= 0) return finishPoll(first);
if (nanos <= 0) return null;
if (nanos < delay || leader != null) nanos = available.awaitNanos(nanos);
else {
Thread thisThread = Thread.currentThread();
leader = thisThread;
try {
long timeLeft = available.awaitNanos(delay);
nanos -= delay - timeLeft;
} finally {
if (leader == thisThread) leader = null;
}
}
}
}
} finally {
if (leader == null && queue[0] != null) available.signal();
lock.unlock();
}
}
public RunnableScheduledFuture<?> poll() {
final ReentrantLock lock = this.lock;
lock.lock();
try {
RunnableScheduledFuture<?> first = queue[0];
if (first == null || first.getDelay(NANOSECONDS) > 0) return null;
else return finishPoll(first);
} finally {
lock.unlock();
}
}
/**
* Return first element only if it is expired. Used only by drainTo. Call only when holding
* lock.
*/
private RunnableScheduledFuture<?> peekExpired() {
// assert lock.isHeldByCurrentThread();
RunnableScheduledFuture<?> first = queue[0];
return (first == null || first.getDelay(NANOSECONDS) > 0) ? null : first;
}
