Digital Clock Using Thread in JAVA
this given example is display digital clock for user it takes time from working system and display it on the JFrame with the help of thread and swing package.
Program:
import java.util.*;
import java.text.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class ClockScreen extends JFrame{
private JLabel timeString,lbl_digi;
public JButton start;
Thread t;
public ClockScreen(Thread t){
this.setTitle("Digital Clock");
this.setVisible(true);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setSize(200,130);
this.setLayout(null);
this.setLocation(GraphicsEnvironment.getLocalGraphicsEnvironment().getCenterPoint().x-this.getWidth()/2,GraphicsEnvironment.getLocalGraphicsEnvironment().getCenterPoint().y-this.getHeight()/2);
this.t=t;
Font font = new Font("Courier", Font.BOLD,20);
lbl_digi=new JLabel("Digital Clock");
lbl_digi.setBounds(10,10,180,20);
lbl_digi.setFont(new Font("Vardana",Font.BOLD,16));
lbl_digi.setHorizontalAlignment(JLabel.CENTER);
lbl_digi.setVerticalAlignment(JLabel.CENTER);
timeString=new JLabel();
timeString.setBounds(10,30,180,20);
timeString.setFont(font);
timeString.setHorizontalAlignment(JLabel.CENTER);
timeString.setVerticalAlignment(JLabel.CENTER);
start=new JButton("Stop");
start.setBounds(10,60,180,30);
start.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e){
try{
if(start.getText().equals("stop")){
start.setText("start");
ClockScreen.this.t=Thread.currentThread();
ClockScreen.this.t.yield();
System.out.println("jiten");
}else{
start.setText("stop");
}
}catch(Exception ex){
System.out.println("Error:"+ex.getMessage());
}
}
});
add(timeString);
add(lbl_digi);
add(start);
}
public void setLabelValue(String value){
timeString.setText(value);
}
}
class clock implements Runnable{
int hour,minute,second;
String strTime;
private Thread t;
private ClockScreen c1;
private String threadName;
public clock( String name){
threadName = name;
System.out.println("Creating " + threadName );
c1=new ClockScreen(t);
}
public void run() {
System.out.println("Running " + threadName );
try {
int i=Calendar.getInstance().get(Calendar.SECOND);
while(true){
Calendar cal=Calendar.getInstance();
hour=cal.get(Calendar.HOUR_OF_DAY);
if(hour >12)
hour-=12;
minute=cal.get(Calendar.MINUTE);
second=cal.get(Calendar.SECOND);
SimpleDateFormat formatter=new SimpleDateFormat("HH:mm:ss");
Date date=cal.getTime();
strTime=formatter.format(date);
System.out.println(strTime);
System.out.println("Thread: " + threadName + ", " + second+"\t i:"+(i));
c1.setLabelValue(strTime);
/*if((second-i)>=10)
System.exit(0);*/
Thread.sleep(1000);
}
} catch (InterruptedException e) {
System.out.println("Thread " + threadName + " interrupted.");
}
System.out.println("Thread " + threadName + " exiting.");
}
public void start ()
{
System.out.println("Starting " + threadName );
if (t == null)
{
t = new Thread (this, threadName);
t.start ();
}
}
}
public class DigitalClock{
public static void main(String [] args){
clock c1=new clock("First");
c1.start();
}
}
run this program by following command:
<complilation>$javac DigitalClock.java
<run>$ java DigitalClock