Create a Digital Clock in Java

Digital Clock

Download DigitalClock.java
Digital Clock class:

/**
 * @author Eri Setiawan
 */

import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;

public class DigitalClock extends JLabel {
 private String pattern;
 private Timer timer;
 private int delay;

 /**
  * Constructs a Digital Clock using the given pattern and the default delay.
  * @param pattern - the pattern describing the date and time format
  */
 public DigitalClock(String pattern){
  this.pattern = pattern;
  this.delay = 1000;
  createTimer();
  timer.start();
 }
 
 /**
  * Constructs a Digital Clock using the given pattern and delay.
  * @param delay - the number of milliseconds between action events
  * @param pattern - the pattern describing the date and time format
  */

 public DigitalClock(String pattern, int delay){
  this.pattern = pattern;
  this.delay = delay;
  createTimer();
  timer.start();
 }

 /**
  * Constructs a Digital Clock using the default pattern and delay.
  */

 public DigitalClock(){
  pattern = "hh:mm:ss a";
  this.delay = 1000;
  createTimer();
  timer.start();
 }

 private void createTimer(){
  timer = new Timer(delay, new ActionListener() {
   @Override
   public void actionPerformed(ActionEvent arg0) {
    setText(new SimpleDateFormat(pattern).format(new Date()));
   }
  });
 }
 
 public String getPattern() {
  return pattern;
 }
 
 public void setPattern(String pattern) {
  this.pattern = pattern;
 }
 
 public Timer getTimer() {
  return timer;
 }
 
 public int getDelay() {
  return delay;
 }
 
 public void setDelay(int delay) {
  this.delay = delay;
 }
 
 public static void main(String[] args){
  JFrame frame = new JFrame();
  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  frame.setBounds(100, 100, 193, 72);
  JPanel contentPane = new JPanel();
  frame.setContentPane(contentPane);
  contentPane.setLayout(new FlowLayout(FlowLayout.CENTER, 5, 5));
  DigitalClock digitalClock = new DigitalClock();
  contentPane.add(digitalClock);
  frame.setVisible(true);
 }
}