Java併發——Exchanger

Exchanger

Exchanger的功能可以使2個線程之間傳輸數據,它比生產者/消費者模式使用的 wait/notify要更加方便。

exchange()阻塞的特性：

public class ThreadA extends Thread{
    private Exchanger<String> exchanger;

    public ThreadA(Exchanger<String> exchanger) {
        this.exchanger = exchanger;
    }

    @Override
    public void run() {
        try {
            System.out.println("在線程A中得到線程B的值=" + exchanger.exchange("A"));
            System.out.println("A end!");
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        Exchanger<String> exchanger = new Exchanger<>();
        ThreadA a = new ThreadA(exchanger);
        a.start();
        System.out.println("main end");
    }
}

exchange()傳遞數據：

public class ThreadA extends Thread{
    private Exchanger<String> exchanger;

    public ThreadA(Exchanger<String> exchanger) {
        this.exchanger = exchanger;
    }

    @Override
    public void run() {
        try {
            System.out.println("在線程A中得到線程B的值=" + exchanger.exchange("A"));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

public class ThreadB extends Thread {
    private Exchanger<String> exchanger;

    public ThreadB(Exchanger<String> exchanger) {
        this.exchanger = exchanger;
    }

    @Override
    public void run() {
        try {
            System.out.println("在線程B中得到線程A的值=" + exchanger.exchange("B"));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        Exchanger<String> exchanger = new Exchanger<>();
        ThreadA a = new ThreadA(exchanger);
        ThreadB b = new ThreadB(exchanger);
        a.start();
        b.start();
    }
}

exchange(V x, long timeout, TimeUnit unit)與超時：

當調用 exchange(Vx, long timeout, TimeUnit unit)方法後在指定的時間內沒有其他線程獲取數據,則出現超時異常。

public class ThreadA extends Thread{
    private Exchanger<String> exchanger;

    public ThreadA(Exchanger<String> exchanger) {
        this.exchanger = exchanger;
    }

    @Override
    public void run() {
        try {
            System.out.println("在線程A中得到線程B的值=" + exchanger.exchange("A", 5, TimeUnit.SECONDS));
            System.out.println("A end!");
        } catch (InterruptedException | TimeoutException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        Exchanger<String> exchanger = new Exchanger<>();
        ThreadA a = new ThreadA(exchanger);
        a.start();
        System.out.println("main end");
    }
}