Java多线程之Wait()和Notify()

1.Wait()和Notify、NotifyAll都是Object的方法

2.多线程的协作是通过控制同一个对象的Wait()和Notify()完成

3.当调用Wait()方法时，当前线程进入阻塞状态，直到有另一线程调用了该对象的Notify()方法

package Thread.Wait;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

class Car {
    private boolean waxOn = false;

    //上蜡
    public synchronized void waxed() {
        waxOn = true;
        notifyAll();
    }

    //抛光
    public synchronized void buffed() {
        waxOn = false;
        notifyAll();
    }

    public synchronized void waitForWaxing() throws InterruptedException {
        while (waxOn == false)
            wait();
    }

    public synchronized void waitForBuffing() throws InterruptedException {
        while (waxOn == true)
            wait();
    }
}

class WaxOn implements Runnable {
    private Car car;

    public WaxOn(Car c) {
        car = c;
    }

    @Override
    public void run() {
        try {
            while (!Thread.interrupted()) {
                System.out.println("Wax On!");
                TimeUnit.MILLISECONDS.sleep(200);
                car.waxed();//上完蜡  waxOn = true;notifyAll();
                car.waitForBuffing();//等待抛光while (waxOn == true) wait();
            }
        } catch (Exception e) {
            System.out.println("Exiting via interrupt");
        }
        System.out.println("Ending Wax On task");
    }
}

class WaxOff implements Runnable {
    private Car car;

    public WaxOff(Car c) {
        car = c;
    }

    @Override
    public void run() {
        try {
            while (!Thread.interrupted()) {
                car.waitForWaxing();//等待上蜡   while (waxOn == false) wait();
                System.out.println("Wax Off!");
                TimeUnit.MILLISECONDS.sleep(200);
                car.buffed();//已经抛光  waxOn = false;    notifyAll();
            }
        } catch (Exception e) {
            System.out.println("Exiting via interrupt");
        }
        System.out.println("Ending Wax Off task");
    }
}

public class WaxOMatic {
    public static void main(String[] args) throws Exception {
        Car car = new Car();
        ExecutorService exec = Executors.newCachedThreadPool();
        exec.execute(new WaxOff(car));
        exec.execute(new WaxOn(car));
        TimeUnit.SECONDS.sleep(5);
        exec.shutdownNow();
    }
}