java多线程之生存者与消费者(Java编程思想)

package Produce;

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

class Meal {

    private final int orderNum;

    public Meal(int orderNum) {
        this.orderNum = orderNum;
    }

    @Override
    public String toString() {
        return "Meal " + orderNum;
    }
}

class WaitPerson implements Runnable {
    private Restaurant restaurant;

    public WaitPerson(Restaurant r) {
        restaurant = r;
    }

    @Override
    public void run() {
        try {
            while (!Thread.interrupted()) {
                synchronized (this) {
                    while (restaurant.meal == null)
                        wait(); // 等待chef生产meal
                }
                System.out.println("Waitperson got " + restaurant.meal);
                synchronized (restaurant.chef) {
                    restaurant.meal = null;
                    restaurant.chef.notifyAll();// 通知chef继续生产
                }
            }
        } catch (InterruptedException e) {
            System.out.println("WaitPerson interrupted");
        }
    }
}

class Chef implements Runnable {

    private Restaurant restaurant;
    private int count = 0;

    public Chef(Restaurant r) {
        restaurant = r;
    }

    @Override
    public void run() {
        try {
            while (!Thread.interrupted()) {
                synchronized (this) {
                    while (restaurant.meal != null)
                        wait();// 等待meal被拿走
                }
                if (++count == 10) {
                    System.out.println("Out of food,closing");
                    restaurant.exec.shutdownNow();//向每个线程发送Interrupt
                     return;//如果没有直接return 将多执行了下面的 Order up ,所以一般情况下都要直接return
                }

                System.out.println("Order up! ");
                synchronized (restaurant.waitPerson) {
                    // 对notifyAll()的调用必须先获得waitPerson的锁
                    restaurant.meal = new Meal(count);
                    restaurant.waitPerson.notifyAll();
                }
                TimeUnit.MILLISECONDS.sleep(500);//休眠一下是为了给shutdownNow留出时间
            }
        } catch (InterruptedException e) {
            System.out.println("Chef interrupted");
        }
    }
}

public class Restaurant {
    Meal meal;
    ExecutorService exec = Executors.newCachedThreadPool();
    WaitPerson waitPerson = new WaitPerson(this);
    Chef chef = new Chef(this);

    public Restaurant() {
        exec.execute(chef);
        exec.execute(waitPerson);
    }

    public static void main(String[] args) {
        new Restaurant();
    }
}

package Produce;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

class Car {
    private Lock lock = new ReentrantLock();
    private Condition condition = lock.newCondition();
    private boolean waxOn = false;

    public void waxed() {
        lock.lock();
        try {
            waxOn = true;// Ready to buff
            condition.signalAll();
        } finally {
            lock.unlock();
        }
    }

    public void buffed() {
        lock.lock();
        try {
            waxOn = false;// Ready for another coat of wax
            condition.signalAll();
        } finally {
            lock.unlock();
        }
    }

    public void waitForWaxing() throws InterruptedException {
        lock.lock();
        try {
            while (waxOn == false)
                condition.await();
        } finally {
            lock.unlock();
        }
    }

    public void waitForBuffing() throws InterruptedException {
        lock.lock();
        try {
            while (waxOn == true)
                condition.await();
        } finally {
            lock.unlock();
        }
    }
}

class WaxOn implements Runnable {
    private Car car;

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

    @Override
    public void run() {
        try {
            while (!Thread.interrupted()) 
//            while (true) //与使用这行效果一样
            {
                System.out.println("Wax On!");
                TimeUnit.MILLISECONDS.sleep(200);
                car.waxed();
                car.waitForBuffing();
            }
        } catch (InterruptedException 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()) 
//                while (true) 
                    
            {
                car.waitForWaxing();
                System.out.println("Wax Off!");
                TimeUnit.MILLISECONDS.sleep(200);
                car.buffed();
            }
        } catch (InterruptedException e) {
            System.out.println("Exiting via interrupt");
        }
        System.out.println("Ending Wax Off task");
    }
}

public class WaxOMatic2 {
    public static void main(String[] args) throws InterruptedException {
        Car car = new Car();
        ExecutorService exec = Executors.newCachedThreadPool();
        exec.execute(new WaxOff(car));
        exec.execute(new WaxOn(car));
        TimeUnit.SECONDS.sleep(5);
        exec.shutdownNow();
    }
}