介绍

与synchronized类似，Lock中的为 await() , signal , signalAll()。await()将线程添加到对应的条件队列，signal是将对应的条件队列中等待时间最长的节点放入等待队列中，signalAll()是将条件队列中的所有节点放入等待队列中

使用

来简单使用下，实现一个阻塞队列

class BoundedBlockingQueue {
    private final Lock lock = new ReentrantLock();
    private final Condition empty = lock.newCondition();
    private final Condition full = lock.newCondition();
    private final int CAPACITY;
    private Queue<Integer>  q = new LinkedList<>();
    public BoundedBlockingQueue(int capacity) {
        this.CAPACITY = capacity;
    }
    public void enqueue(int element) throws InterruptedException {
        lock.lock();
        try{
            while(q.size() == CAPACITY){
                full.await();
            }
            q.offer(element);
            empty.signalAll();
        }finally {
            lock.unlock();
        }
    }
    public int dequeue() throws InterruptedException {
        lock.lock();
        try{
            while(q.isEmpty()){
                empty.await();
            }
            int res = q.poll();
            full.signalAll();
            return res;
        }finally {
            lock.unlock();
        }
    }
    public int size() {
        lock.lock();
        try{
            return q.size();
        }finally {
            lock.unlock();
        }
    }
}