This program demonstrates the use of inner classes
/* This program is a part of the companion code for Core Java 8th ed. (http://horstmann.com/corejava) This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ import java.awt.Toolkit; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.util.Date; import javax.swing.JOptionPane; import javax.swing.Timer; /** * This program demonstrates the use of inner classes. * @version 1.10 2004-02-27 * @author Cay Horstmann */ public class InnerClassTest { public static void main(String[] args) { TalkingClock clock = new TalkingClock(1000, true); clock.start(); // keep program running until user selects "Ok" JOptionPane.showMessageDialog(null, "Quit program?"); System.exit(0); } } /** * A clock that prints the time in regular intervals. */ class TalkingClock { /** * Constructs a talking clock * @param interval the interval between messages (in milliseconds) * @param beep true if the clock should beep */ public TalkingClock(int interval, boolean beep) { this.interval = interval; this.beep = beep; } /** * Starts the clock. */ public void start() { ActionListener listener = new TimePrinter(); Timer t = new Timer(interval, listener); t.start(); } private int interval; private boolean beep; public class TimePrinter implements ActionListener { public void actionPerformed(ActionEvent event) { Date now = new Date(); System.out.println("At the tone, the time is " + now); if (beep) Toolkit.getDefaultToolkit().beep(); } } }