bank.java

java编程开发技巧与实例的编译测试通过的所有例程

import java.awt.*;
import java.awt.event.*;

public class Bank extends Frame implements ActionListener
{
	//GUI component
	private	Label		status	=	new	Label("Transfers completed: 0");
	private	TextArea	display	=	new	TextArea();
	private	Button	show		=	new	Button("show accounts");
	private	Button	start		=	new	Button("restart");
	private	Button	stop		=	new	Button("stop");
	//--end
	protected	final static int NUM_ACCOUNTS	=	8;
	private 	final static int WASTE_TIME		=	1;
	
	private	int accounts[]		=	new int[NUM_ACCOUNTS];
	private	Customer customer[]	=	new Customer[NUM_ACCOUNTS];
	private	int counter	=	0;
	
	public Bank()
	{
		super("mystery money");
		Panel buttons	=	new	Panel();
		buttons.setLayout(new FlowLayout());
		buttons.add(show);
		show.addActionListener(this);
		buttons.add(start);
		start.addActionListener(this);
		buttons.add(stop);
		stop.addActionListener(this);
		add("North", status);
		add("South", buttons);
		add("Center", display);

		for (int i = 0; i < accounts.length; i ++)
			accounts[i]	=	100000;
		start();
		validate();
		setSize(700, 300);
		setVisible(true);
		addWindowListener(new WindowAdapter()
		{
			public void windowClosing(WindowEvent we)
			{	System.exit(0);	}
		}
		);
	}
	public synchronized void transfer(int from, int into, int amount)
	{
		if ((accounts[from] >= amount) && (from != into))
		{
			int newAmountFrom	=	accounts[from] - amount;
			int newAmountTo		=	accounts[into] + amount;
			wasteSomeTime();
			accounts[from]	=	newAmountFrom;
			accounts[into]	=	newAmountTo;
		}
		status.setText("transfers completed: " + counter ++);
	}
	private void start()
	{
		stop();
		for	(int i = 0; i < accounts.length; i ++)
			customer[i]	=	new Customer(i, this);
	}
	private void stop()
	{
		for (int i = 0; i < accounts.length; i ++)
		{
			if (customer[i] != null)
				customer[i].halt();
		}
	}
	private void wasteSomeTime()
	{
		try
		{	Thread.sleep(WASTE_TIME);	}
		catch	(InterruptedException ie)
		{	System.err.println("Error: " + ie);	}
	}
	private void showAccounts()
	{
		int	sum	=	0;
		for (int i = 0; i < accounts.length; i ++)
		{
			sum	+=	accounts[i];
			display.append("\naccount " + i + ": $" + accounts[i]);
		}
		display.append("\ntotal amount: $" + sum);
		display.append("\ntotal transfers: " + counter + "\n");
	}
	public void actionPerformed(ActionEvent ae)
	{
		if (ae.getSource() == show)
			showAccounts();
		else if (ae.getSource() == start)
			start();
		else if (ae.getSource() == stop)
			stop();
	}
	public static void main(String args[])
	{
		Bank bank	=	new Bank();
	}
}