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  

  8  /**

  9     This program displays the growth of an investment. 

 10  */

 11  public class InvestmentViewer2

 12  {  

 13     private static final int FRAME_WIDTH = 400;

 14     private static final int FRAME_HEIGHT = 100;

 15  

 16     private static final double INTEREST_RATE = 10;

 17     private static final double INITIAL_BALANCE = 1000;

 18  

 19     public static void main(String[] args)

 20     {  

 21        JFrame frame = new JFrame();

 22  

 23        // The button to trigger the calculation

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

 25  

 26        // The application adds interest to this bank account

 27        final BankAccount account = new BankAccount(INITIAL_BALANCE);

 28  

 29        // The label for displaying the results

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

 31  

 32        // The panel that holds the user interface components

 33        JPanel panel = new JPanel();

 34        panel.add(button);

 35        panel.add(label);      

 36        frame.add(panel);

 37    

 38        class AddInterestListener implements ActionListener

 39        {

 40           public void actionPerformed(ActionEvent event)

 41           {

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

 43              account.deposit(interest);

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

 45           }            

 46        }

 47  

 48        ActionListener listener = new AddInterestListener();

 49        button.addActionListener(listener);

 50  

 51        frame.setSize(FRAME_WIDTH, FRAME_HEIGHT);

 52        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

 53        frame.setVisible(true);

 54     }

 55  }