实验题目：用Java的等待/通知机制实现“厨师—食 者”问题。假设分别有4位厨师和6位食者。厨师做一盘 菜的时间为4s，食者吃一盘菜的时间为3s。编程实现这 一功能，参考“生产者—消费者”问题。

Food类

package cook_eat;

public class Food {

}

Cook类

package cook_eat;

public class Cook extends Thread{

        private Table table;
        
        public Cook(Table table) {
                this.table = table;
        }

        @Override
        public void run() {
                while(true) {
                        // 做菜
                        Food food = new Food();
                        // 需要四秒
                        try {
                                Thread.sleep(4000);
                        } catch (Exception e) {
                                e.printStackTrace();
                        }
                        // 上菜
                        table.putFood(food);
                }
        }
        
}

Eater类

package cook_eat;

public class Eater extends Thread{

        private Table table;
        
        public Eater(Table table) {
                this.table = table;
        }
        
        @Override
        public void run() {
                while(true) {
                        // 吃菜
                        Food food = table.getFood();
                        // 需要三秒
                        try {
                                Thread.sleep(3000);
                        } catch (Exception e) {
                                e.printStackTrace();
                        }
                }
        }

}

Table类

package cook_eat;

import java.util.LinkedList;

class Table extends LinkedList<Object> {
        int maxSize; // 容器的最大容量
 
        public Table(int maxSize) {
                this.maxSize = maxSize;
        }
        public synchronized void putFood(Food f) { // 向容器内放置食品
                
                while (this.size() >= this.maxSize) {
                        try {
                                System.out.println("The table is too full,wait a moment!");
                                wait();
                        } catch (Exception e) {
                        }
                }
                this.addLast(f);
                System.out.println("厨师上一份菜，现在桌上还有有"+this.size()+"份菜");
                notifyAll();
        }
 
        public synchronized Food getFood() { // 从容器内取食品
                Food f;
                while (this.size() <= 0) {
                        try {
                                System.out.println("There is no food now ,come here later!");
                                wait();
                        } catch (Exception e) {
                        }
                }
                f = (Food) this.getFirst();
                this.remove(f);
                System.out.println("食客吃了一份菜，现在桌上有"+this.size()+"份菜");
                notifyAll();
                return f;
        }
}

Test类

package cook_eat;

public class Test {

        public static void main(String[] args) {
                // 假定一开始桌上有六道菜
                Table table = new Table(6);
                // 厨师开始做菜
                new Cook(table).start();
                new Cook(table).start();
                new Cook(table).start();
                new Cook(table).start();
                // 食客开始吃菜
                new Eater(table).start();
                new Eater(table).start();
                new Eater(table).start();
                new Eater(table).start();
                new Eater(table).start();
                new Eater(table).start();
        }

}