cardbuffer.java

这是一个Java编写的发牌小程序

//【例7.8】  发牌程序。

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class CardBuffer                    //加互斥锁的缓冲区
{
    private int value;
    private boolean isEmpty = true;        //value是否为空的信号量
    private int order=0;                   //信号量，约定取牌线程的次序
    
    synchronized void put(int i)
    {
        while (!isEmpty)                   //当value不空时，等待
        {
            try
            {
                 this.wait();              //等待
            }
            catch(InterruptedException e) {}
        }
        
        value = i;                         //当value空时，value获得值
        isEmpty = false;                   //设置value为不空状态
        notifyAll();                       //唤醒所有其他等待线程
    }
    
    synchronized int get(int order)        //order是取牌线程约定的次序
    {
        while (isEmpty || (this.order!=order))   //当value空或取牌次序不符时等待
        {                                  
            try
            {
                 this.wait();
            }
            catch(InterruptedException e) {}
        }
        
        isEmpty = true;                    //设置value为空状态，并返回值
        notifyAll();
        this.order = (this.order+1)%4;     //加1使取牌次序轮转
        return value;                      
    }
}

class Sender extends Thread               //发牌线程类
{
    private CardBuffer cardbuffer;
    private int count;
    
    public Sender(CardBuffer cardbuffer,int count)
    {
        this.cardbuffer = cardbuffer;
        this.count = count;
    }
    
    public void run()
    {
        for (int i=1;i<=this.count;i++)
            cardbuffer.put(i);
    }
}

class Receiver extends Thread             //取牌线程类
{
    private CardBuffer cardbuffer;
    private JTextArea text;
    private int order;                    //信号量，约定取牌线程的次序
    
    public Receiver(CardBuffer cardbuffer,JTextArea text,int order)
    {
        this.cardbuffer = cardbuffer ;
        this.text = text ;
        this.order = order;
    }
    
    public void run()
    {
        while(true)
        {
            text.append(" "+cardbuffer.get(this.order));
            try
            {
                 this.sleep(100);
            }
            catch(InterruptedException e) {}
        }
    }
}

class CardJFrame extends JFrame
{
    public CardJFrame()
    {
        super("发牌程序");
        
        this.setSize(430,200);
        this.setLocation(300,240);
        this.setDefaultCloseOperation(EXIT_ON_CLOSE);
        this.setLayout(new GridLayout(3,3,5,5));           //3行3列网格布局，间隔为5
        
        JTextArea text_north,text_east,text_south,text_west;  //获得牌的4个文本区
        text_north = new JTextArea();
        text_east = new JTextArea();
        text_south = new JTextArea();
        text_west = new JTextArea();
        
        text_north.setLineWrap(true);                      //设置文本区自动换行
        text_east.setLineWrap(true); 
        text_south.setLineWrap(true); 
        text_west.setLineWrap(true); 
        
        text_north.setEditable(false);
        text_east.setEditable(false);
        text_south.setEditable(false);
        text_west.setEditable(false);
        
        Font font = new Font("Helvetica", Font.PLAIN, 16);
        text_north.setFont(font);
        text_east.setFont(font);
        text_south.setFont(font);
        text_west.setFont(font);
        
        this.add(new JPanel());                            //网格布局的第1行
        this.add(text_north);
        this.add(new JPanel());
        
        this.add(text_west);                               //网格布局的第2行
        this.add(new JPanel());
        this.add(text_east);
        
        this.add(new JPanel());                            //网格布局的第3行
        this.add(text_south);
        this.add(new JPanel());
        this.setVisible(true);
        
        CardBuffer cardbuffer = new CardBuffer();
        Sender s = new Sender(cardbuffer,52);
        s.setPriority(10);                                 //设置最高优先级
        s.start();                                         //启动发牌线程
        
        (new Receiver(cardbuffer,text_north,0)).start();   //创建并启动4个取牌线程，优先级为5
        (new Receiver(cardbuffer,text_east,1)).start();
        (new Receiver(cardbuffer,text_south,2)).start();
        (new Receiver(cardbuffer,text_west,3)).start();
    }

    public static void main(String arg[])
    {
        new CardJFrame();
    }
}