signalAll方法

public final void signalAll() {
	if (!isHeldExclusively())
		throw new IllegalMonitorStateException();
	Node first = firstWaiter;
	if (first != null)
		// 如果condition链表不为空，唤醒链表中所有的节点，并且放入AQS链表中
		doSignalAll(first);
}

private void doSignalAll(Node first) {
	lastWaiter = firstWaiter = null;
	do {
		Node next = first.nextWaiter;
		first.nextWaiter = null;
		transferForSignal(first);
		first = next;
	} while (first != null);
}

final boolean transferForSignal(Node node) {
	/*
	 * If cannot change waitStatus, the node has been cancelled.
	 */
	if (!compareAndSetWaitStatus(node, Node.CONDITION, 0))
		return false;

	/*
	 * Splice onto queue and try to set waitStatus of predecessor to
	 * indicate that thread is (probably) waiting. If cancelled or
	 * attempt to set waitStatus fails, wake up to resync (in which
	 * case the waitStatus can be transiently and harmlessly wrong).
	 */
	Node p = enq(node);
	int ws = p.waitStatus;
	if (ws > 0 || !compareAndSetWaitStatus(p, ws, Node.SIGNAL))
		LockSupport.unpark(node.thread);
	return true;
}