diding.java

本程序是关于哲学家进餐问题的描述,具体可以在javabuilder上运行一下

package threadPhilosofor;

  class ChopStick {    //筷子类
      boolean available;
      ChopStick() {
          available=true;  //可以拿起
     }
     public synchronized void takeup() {  //拿起动作
         while(!available) {
             try {
                 wait(); 
                 System.out.println("哲学家等待另一根筷子");  
             } catch(InterruptedException e) { }
         }
         available=false;
     }
     
     public synchronized void putdown() {  //放下动作
         available=true;
         notify();
     }
 }
 
 
 class Philosopher extends Thread {   //哲学家类
     ChopStick left, right;  
     int philo_num;  //哲学家编号
     
     Philosopher (int num, ChopStick c1, ChopStick c2) {
         philo_num = num;
         left = c1;
         right = c2;
         setDaemon(true);  //此函数设true时，关闭主线程，子线程也跟着关闭
         //否则，关闭主线程，子线程继续执行
     }
     
     public void eat() {
         left.takeup();
         right.takeup();
         System.out.println("哲学家 " + (philo_num + 1) + " 正在进餐");
     }
     
     public void think() {
         left.putdown();
         right.putdown();
         System.out.println("哲学家 " + (philo_num + 1) + " 正在思考");
     }
     
     public void run() {
         while(true) {
             eat();
             
             try {
                 sleep(2000);  //吃的时间是2秒
             }
             catch (InterruptedException e) {}
 
             think();
             
             try {
                 sleep(2000);   //思考的时间也是2秒
             }
             catch (InterruptedException e) {}
         }
    }
 }
 
 
 public class DiDing {      
     static ChopStick[] chopsticks = new ChopStick[5];  
     static Philosopher[] philos = new Philosopher[5];
     
     public static void main(String args[]) {
         for (int i = 0; i < 5; i ++ ) {
             chopsticks[i] = new ChopStick();
         }
         
         for (int i = 0; i < 5; i ++ ) {
             philos[i] = new Philosopher(i, chopsticks[i], chopsticks[(i + 1) % 5]);
         }
         
         for (int i = 0; i < 5; i ++) {
             philos[i].start();
         }
         
         try
         {
             System.in.read(); //wait until Enter is pressed
             for (int i = 0; i < 5; i ++) {
             
                 philos[i].interrupt(); 
             }
         }
         catch(Exception e)
         { }
     }
  }