java Java实现的生产者和消费者问题

Posted 2021-05-07

import java.util.concurrent.*;

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) throws ExecutionException, InterruptedException {
        new Restaurant();
    }
}

interface StupidPrint {
    default void print(String s) {
        System.out.print(s+" ");
    }

    default void printnb(String s) {
        System.out.println(s);
    }
}

class Meal implements StupidPrint {
    private final int orderNum;

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

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

class WaitPerson implements Runnable, StupidPrint {
    private Restaurant restaurant;

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

    public void run() {
        try {
            while (!Thread.interrupted()) {
                synchronized (this) {
                    while (restaurant.meal == null) wait();
                }
                print("Waitperson got " + restaurant.meal);
                synchronized (restaurant.chef) {
                    restaurant.meal = null;
                    restaurant.chef.notifyAll();
                }
            }
        } catch (InterruptedException e) {
            print("WaitPerson interrupted");
        }
    }
}

class Chef implements Runnable, StupidPrint {
    private Restaurant restaurant;
    private int count = 0;

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

    public void run() {
        try {
            while (!Thread.interrupted()) {
                synchronized (this) {
                    while (restaurant.meal != null) wait();
                }
                if (++count == 10) {
                    printnb("Out of food, closing");
                    restaurant.exec.shutdownNow();
                    TimeUnit.MILLISECONDS.sleep(100); // in order to show the message of Chef interrupted
                }
                printnb("Order up! ");
                synchronized (restaurant.waitPerson) {
                    restaurant.meal = new Meal(count);
                    restaurant.waitPerson.notifyAll();
                }
                TimeUnit.MILLISECONDS.sleep(100);
            }
        } catch (InterruptedException e) {
            print("Chef interrupted");
        }
    }
}