bank.java

Java程序设计技巧与开发实例附书源代码。

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

public class Bank
        extends Frame
        implements ActionListener
{
    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");

    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);
        setLayout(new BorderLayout());
        add("North", status);
        add("South", buttons);
        add("Center", display);

        for (int i = 0; i < accounts.length; i++)
        {
            accounts[i] = 100000;
        }
        start(); //是普通的方法，并非线程的start方法
        validate();
        setSize(300, 300);
        setVisible(true);
        addWindowListener(new WindowAdapter()
        {
            public void windowClosing(WindowEvent we)
            {
                System.exit(0);
            }
        });

    }

    public 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()
    {
        /* shows account information for all accounts */

        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 static void main(String args[])
    {
        Bank bank = new Bank();
    }

    public void actionPerformed(ActionEvent ae)
    {
        if (ae.getSource() == show)
        {
            showAccounts();
        }
        else if (ae.getSource() == start)
        {
            start();
        }
        else if (ae.getSource() == stop)
        {
            stop();
        }
    }
}