Interfaces and Polymorphism - Java Concepts - page 572

13 {
14 public static void main(String[] args)
15 {
16 JFrame frame = new JFrame();
17
18 // The button to trigger the calculation
19 JButton button = new JButton( "Add
Interest" );
20
21 // The application adds interest to this bank account
22 final BankAccount account = new
BankAccount(INITIAL_BALANCE);
23
24 // The label for displaying the results
25 final JLabel label = new JLabel(
26 "balance: " +
account.getBalance());
27
28 // The panel that holds the user interface components
29 JPanel panel = new JPanel();
30 panel.add(button);
31 panel.add(label);
32 frame.add(panel);
33
34 class AddInterestListener implements
ActionListener
35 {
36 public void
actionPerformed(ActionEvent event)
37 {
38 double interest =
account.getBalance()
39 * INTEREST_RATE / 100 ;
40 account.deposit(interest);
41 label.setText(
42 "balance: " +
account.getBalance());
43 }
44 }
45
46 ActionListener listener = new
AddInterestListener();
47 button.addActionListener(listener);
48

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