Thinking in java部分答案

//package number27; import java.util.concurrent.*; import java.util.concurrent.locks.Condition; import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReentrantLock; class Meal { private final int orderNum; public Meal(int orderNum) { this.orderNum = orderNum; } public String toString() { return "Meal " + orderNum; } } class WaitPerson implements Runnable { private Restaurant restaurant; public WaitPerson(Restaurant r) { restaurant = r; } public Lock lock = new ReentrantLock(); public Condition condition=lock.newCondition(); public void run() { try { while(!Thread.interrupted()) { lock.lock(); try { while(restaurant.meal == null) condition.await(); // ... for the chef to produce a meal } finally { lock.unlock(); } System.out.println("Waitperson got " + restaurant.meal); restaurant.chef.lock.lock(); try { restaurant.meal = null; restaurant.chef.condition.signalAll(); } finally { restaurant.chef.lock.unlock(); } } } 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; } public Lock lock = new ReentrantLock(); public Condition condition=lock.newCondition(); public void run() { try { while(!Thread.interrupted()) { lock.lock(); try { while(restaurant.meal != null) condition.await(); // ... for the meal to be taken } finally { lock.unlock(); } if(++count == 10) { System.out.println("Out of food, closing"); restaurant.exec.shutdownNow(); } System.out.println("Order up! "); restaurant.waitPerson.lock.lock(); try { restaurant.meal = new Meal(count); restaurant.waitPerson.condition.signalAll(); } finally { restaurant.waitPerson.lock.unlock(); } TimeUnit.MILLISECONDS.sleep(100); } } 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(); } }