example09_synchronized_business.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_Business extends JFrame implements ActionListener
{
	JTextField inputMoney;
	JButton setMoney;
	JButton getMoney;
	JTextArea list;
	Account account;
	
	public Example09_Synchronized_Business()
	{
		super("Synchronized");
		setDefaultCloseOperation(EXIT_ON_CLOSE);
		
		inputMoney = new JTextField(8);
		
		setMoney = new JButton("购货商存款");
		setMoney.addActionListener(this);
		
		getMoney = new JButton("供货商取款");
		getMoney.addActionListener(this);
		
		list = new JTextArea(20, 30);
		list.setEditable(false);
		
		JPanel p = new JPanel();
		p.add(new JLabel("请输入应付款"));
		p.add(inputMoney);
		p.add(setMoney);
		p.add(getMoney);
		
		Container con = getContentPane();
		con.add(p, "North");
		con.add(new JScrollPane(list), "Center");
		
		setVisible(true);
		pack();

		account = new Account(list);
	}
	
	public void actionPerformed(ActionEvent evt)
	{
		if (evt.getSource() == setMoney)
		{
			String mstr = JOptionPane.showInputDialog(this, "请输入存款金额");
			int m = Integer.parseInt(mstr);
			account.setMoney(m);
		}
		
		if (evt.getSource() == getMoney)
		{
			int m = Integer.parseInt(inputMoney.getText());
			account.getMoney(m);
		}
	}
	
	public static void main(String[] args)
	{
		new Example09_Synchronized_Business();
	}
}

class Account
{
	int money = 0;
	JTextArea list;
	
	public Account(JTextArea list)
	{
		this.list = list;
		this.list.append("当前帐户余额为：" + money + "（元）\n");
	}
	
	public void setMoney(int m)
	{
		synchronized(this)
		{
			money += m;
			list.append("购货商存入：" + m + "（元），当前余额为：" + money + "（元）\n");
		}
	}
	
	public boolean getMoney(int m)
	{
		synchronized(this)
		{
			while (m > money)
			{
				list.append("余额不足，交易不能完成，等待中...！\n");
				return false;
			}
			
			money -= m;
			list.append("交易完成，当前余额为：" + money + "（元）\n");
			return true;
		}
	}
}list.append("交易完成，当前余额为：" + money + "（元）\n");
			return true;
		}
	}
}