example09_synchronized_ticket.java

这是我java课程第九章的作业,也是实现多线程的技术.

package example.ch09;

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

public class Example09_Synchronized_Ticket extends JFrame implements ActionListener
{
	JButton newBuyer;
	JTextArea list;
	Saler saler;
	int no;
	
	public Example09_Synchronized_Ticket()
	{
		super("Synchronized");
		setDefaultCloseOperation(EXIT_ON_CLOSE);
		
		Font font = new Font("宋体", Font.BOLD, 20);
		
		newBuyer = new JButton("创建一个买票者");
		newBuyer.setFont(font);
		newBuyer.addActionListener(this);
		
		list = new JTextArea("waiting for buyer ...\n");
		list.setFont(font);
		list.setEditable(false);

		Container con = getContentPane();
		con.add(newBuyer, "North");
		con.add(new JScrollPane(list), "Center");
		
		setExtendedState(MAXIMIZED_BOTH);
		setVisible(true);
		
		saler = new Saler(list);
		no = 1;
	}
	
	public void actionPerformed(ActionEvent evt)
	{
		Buyer buyer = new Buyer(saler, no ++);
		buyer.start();
	}
	
	public static void main(String[] args)
	{
		new Example09_Synchronized_Ticket();
	}
}

class Saler
{
	JTextArea list;
	int count, n5, n10;
	
	public Saler(JTextArea list)
	{
		this.list = list;
		count = n5 = n10 = 0;
	}
	
	public synchronized void saleTicket(int no, int giveMoney)
	{
		list.append("\nThe buyer No." + no + " holds " + giveMoney + " 元买票 ...\n");

		if (giveMoney == 5)
		{
			n5 ++;
		}
		
		if (giveMoney == 10)
		{
			while (n5 < 1)
			{
				try
				{
					wait();
				}
				catch (InterruptedException e)
				{
					e.printStackTrace();
				}
			}
			
			n5 --;
			n10 ++;
		}
		
		count ++;
		list.append("\nThe buyer No." + no + " 买票成功！\n");
		list.append(getResult() + "\n");
			
		notifyAll();
	}
	
	public String getResult()
	{
		int money = n5 * 5 + n10 * 10;
		
		String result = "Total = " + money + " ; " + 
						"Count = " + count + " ; " + 
						"n5 = " + n5 + " ; " + 
						"n10 = " + n10;
		
		return result;
	}
}

class Buyer extends Thread
{
	Saler saler;
	int no;
	
	public Buyer(Saler saler, int no)
	{
		this.saler = saler;
		this.no = no;
	}
	
	public void run()
	{
		int giveMoney = (int)(1 + Math.random() * 2) * 5;
		
		saler.saleTicket(no, giveMoney);
	}
}Money = (int)(1 + Math.random() * 2) * 5;
		
		saler.saleTicket(no, giveMoney);
	}
}