阻塞队列-BlockingQueue

Queue队列

阻塞队列-BlockingQueue 是一个接口。

BlockingQueue 不是新的东西

四组API

api演示

import java.util.Collection;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.TimeUnit;
public class Test {
    public static void main(String[] args) throws InterruptedException {
        test4();
    }
    /**
     * 抛出异常
     */
    public static void test1(){
        // 队列的大小
        ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);
        System.out.println(blockingQueue.add("a"));
        System.out.println(blockingQueue.add("b"));
        System.out.println(blockingQueue.add("c"));
        // IllegalStateException: Queue full 抛出异常！
        // System.out.println(blockingQueue.add("d"));
        System.out.println("=-===========");
        System.out.println(blockingQueue.element()); // 查看队首元素是谁
        System.out.println(blockingQueue.remove());
        System.out.println(blockingQueue.remove());
        System.out.println(blockingQueue.remove());
        // java.util.NoSuchElementException 抛出异常！
        // System.out.println(blockingQueue.remove());
    }
    /**
     * 有返回值，没有异常
     */
    public static void test2(){
        // 队列的大小
        ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);
        System.out.println(blockingQueue.offer("a"));
        System.out.println(blockingQueue.offer("b"));
        System.out.println(blockingQueue.offer("c"));
        System.out.println(blockingQueue.peek());
        // System.out.println(blockingQueue.offer("d")); // false 不抛出异常！
        System.out.println("============================");
        System.out.println(blockingQueue.poll());
        System.out.println(blockingQueue.poll());
        System.out.println(blockingQueue.poll());
        System.out.println(blockingQueue.poll()); // null  不抛出异常！
    }
    /**
     * 等待，阻塞（一直阻塞）
     */
    public static void test3() throws InterruptedException {
        // 队列的大小
        ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);
        // 一直阻塞
        blockingQueue.put("a");
        blockingQueue.put("b");
        blockingQueue.put("c");
        // blockingQueue.put("d"); // 队列没有位置了，一直阻塞
        System.out.println(blockingQueue.take());
        System.out.println(blockingQueue.take());
        System.out.println(blockingQueue.take());
        System.out.println(blockingQueue.take()); // 没有这个元素，一直阻塞
    }
    /**
     * 等待，阻塞（等待超时）
     */
    public static void test4() throws InterruptedException {
        // 队列的大小
        ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);
        blockingQueue.offer("a");
        blockingQueue.offer("b");
        blockingQueue.offer("c");
        // blockingQueue.offer("d",2,TimeUnit.SECONDS); // 等待超过2秒就退出
        System.out.println("===============");
        System.out.println(blockingQueue.poll());
        System.out.println(blockingQueue.poll());
        System.out.println(blockingQueue.poll());
        blockingQueue.poll(2,TimeUnit.SECONDS); // 等待超过2秒就退出
    }
}