1  import java.awt.event.ActionEvent;

  2  import java.awt.event.ActionListener;

  3  import javax.swing.JButton;

  4  import javax.swing.JFrame;

  5  import javax.swing.JLabel;

  6  import javax.swing.JPanel;

  7  import javax.swing.JTextField;

  8  

  9  /**

 10     This program displays the growth of an investment. 

 11  */

 12  public class InvestmentViewer2

 13  {  

 14     private static final int FRAME_WIDTH = 400;

 15     private static final int FRAME_HEIGHT = 100;

 16  

 17     private static final double INTEREST_RATE = 10;

 18     private static final double INITIAL_BALANCE = 1000;

 19  

 20     public static void main(String[] args)

 21     {  

 22        JFrame frame = new JFrame();

 23  

 24        // The button to trigger the calculation

 25        JButton button = new JButton("Add Interest");

 26  

 27        // The application adds interest to this bank account

 28        final BankAccount account = new BankAccount(INITIAL_BALANCE);

 29  

 30        // The label for displaying the results

 31        final JLabel label = new JLabel("balance: " + account.getBalance());

 32  

 33        // The panel that holds the user interface components

 34        JPanel panel = new JPanel();

 35        panel.add(button);

 36        panel.add(label);      

 37        frame.add(panel);

 38    

 39        class AddInterestListener implements ActionListener

 40        {

 41           public void actionPerformed(ActionEvent event)

 42           {

 43              double interest = account.getBalance() * INTEREST_RATE / 100;

 44              account.deposit(interest);

 45              label.setText("balance: " + account.getBalance());

 46           }            

 47        }

 48  

 49        ActionListener listener = new AddInterestListener();

 50        button.addActionListener(listener);

 51  

 52        frame.setSize(FRAME_WIDTH, FRAME_HEIGHT);

 53        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

 54        frame.setVisible(true);

 55     }

 56  }