9주차 5번문제

P9_5 강의자료에 나오는 InvestmentViewer1 프로그램에서는 AddInterestListener가 inner class로 구현되어 있습니다. 이것을 수정하여 inner class가 아닌 일반 클래스로 만드시오. 힌트: AddInterestListener 구성자가 BankAccount와 JLabel을 파라미터로 갖도록 하면 됩니다.

AddInterestListener package p9_5; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JLabel; public class AddInterestListener implements ActionListener{ public AddInterestListener(BankAccount account, JLabel label){ this.account = account; this.label = label; } public void actionPerformed(ActionEvent event){ double interest = this.account.getBalance() * INTEREST_RATE / 100; this.account.deposit(interest); this.label.setText("balance = " + account.getBalance()); } private static final double INTEREST_RATE = 10; private BankAccount account; private JLabel label; } BankAccount package p9_5; public class BankAccount { public BankAccount() { balance = 0; } public BankAccount(double initialBalance){ balance = initialBalance; } public void deposit(double amount) { double newBalance = balance + amount; balance = newBalance; } public void withdraw(double amount) { double newBalance = balance - amount; balance = newBalance; } public double getBalance() { return balance; } private double balance; } InvetsmentViewer package p9_5; import java.awt.event.ActionListener; import java.awt.event.ActionEvent; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; public class InvestmentViewer{ public static void main(String[] args){ JFrame frame = new JFrame(); JButton button = new JButton("Add Interest"); final BankAccount account = new BankAccount(INITIAL_BALANCE); final JLabel label = new JLabel("balance = " + account.getBalance()); JPanel panel = new JPanel(); panel.add(button); panel.add(label); frame.add(panel); ActionListener listener = new AddInterestListener(account,label); button.addActionListener(listener); frame.setSize(FRAME_WIDTH, FRAME_HEIGHT); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); } private static final double INITIAL_BALANCE = 1000; private static final int FRAME_WIDTH = 400; private static final int FRAME_HEIGHT = 100; }