JUC-BlockingQueue阻塞队列

ArrayBlockingQueue ：一个由数组结构组成的有界阻塞队列
linkedBlockingQueue ：一个由链表结构组成的有界阻塞队列（常用）
PriorityBlockingQueue ：一个支持优先级排序的无界阻塞队列
DelayQueue： 一个使用优先级队列实现的无界阻塞队列
SynchronousQueue： 一个不存储元素的阻塞队列（常用）
linkedTransferQueue： 一个由链表结构组成的无界阻塞队列
linkedBlockingDeque： 一个由链表结构组成的双向阻塞队列

//阻塞队列4组API
public class BlockingQueue_ {

    @Test
    public void test1() {
        BlockingQueue bq = new ArrayBlockingQueue<>(3);

        System.out.println(bq.add("a"));
        System.out.println(bq.add("b"));
        System.out.println(bq.add("c"));
        System.out.println(bq.add("d"));//抛异常

        //Retrieves, but does not remove, the head of this queue.
        System.out.println(bq.element());

        System.out.println(bq.remove());
        System.out.println(bq.remove());
        System.out.println(bq.remove());
        System.out.println(bq.remove());//抛异常
    }

    @Test
    public void test2() {
        BlockingQueue bq = new ArrayBlockingQueue<>(3);

        System.out.println(bq.offer("d"));
        System.out.println(bq.offer("e"));
        System.out.println(bq.offer("f"));
        System.out.println(bq.offer("g"));//返回false

        System.out.println(bq.peek());

        System.out.println(bq.poll());
        System.out.println(bq.poll());
        System.out.println(bq.poll());
        System.out.println(bq.poll());//返回null
    }

    @Test
    public void test3() throws InterruptedException {
        BlockingQueue bq = new ArrayBlockingQueue<>(3);

        bq.put("h");
        bq.put("i");
        bq.put("j");
        //bq.put("k");//一直阻塞
        System.out.println(bq.take());
        System.out.println(bq.take());
        System.out.println(bq.take());
        System.out.println(bq.take());//一直阻塞
    }

    @Test
    public void test4() throws InterruptedException {
        BlockingQueue bq = new ArrayBlockingQueue<>(3);

        System.out.println(bq.offer("l", 2, TimeUnit.SECONDS));
        System.out.println(bq.offer("m", 2, TimeUnit.SECONDS));
        System.out.println(bq.offer("n", 2, TimeUnit.SECONDS));
        System.out.println(bq.offer("o", 2, TimeUnit.SECONDS));//等待定义的单位时间，如果还是无法入队列则返回false

        System.out.println(bq.poll(2, TimeUnit.SECONDS));
        System.out.println(bq.poll(2, TimeUnit.SECONDS));
        System.out.println(bq.poll(2, TimeUnit.SECONDS));
        System.out.println(bq.poll(2, TimeUnit.SECONDS));//等待定义的单位时间，如果还没有可取元素则返回null
    }

}