import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Font;
import java.lang.reflect.InvocationTargetException;
import java.text.DecimalFormat;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingConstants;
import javax.swing.SwingUtilities;
public class DigitalTimer extends JLabel {
private volatile String timeText;
private Thread internalThread;
private volatile boolean noStopRequested;
public DigitalTimer() {
setBorder(BorderFactory.createLineBorder(Color.black));
setHorizontalAlignment(SwingConstants.RIGHT);
setFont(new Font("SansSerif", Font.BOLD, 16));
setText("00000.0"); // use to size component
setMinimumSize(getPreferredSize());
setPreferredSize(getPreferredSize());
setSize(getPreferredSize());
timeText = "0.0";
setText(timeText);
noStopRequested = true;
Runnable r = new Runnable() {
public void run() {
try {
runWork();
} catch (Exception x) {
x.printStackTrace();
}
}
};
internalThread = new Thread(r, "DigitalTimer");
internalThread.start();
}
private void runWork() {
long startTime = System.currentTimeMillis();
int tenths = 0;
long normalSleepTime = 100;
long nextSleepTime = 100;
DecimalFormat fmt = new DecimalFormat("0.0");
Runnable updateText = new Runnable() {
public void run() {
setText(timeText);
}
};
while (noStopRequested) {
try {
Thread.sleep(nextSleepTime);
tenths++;
long currTime = System.currentTimeMillis();
long elapsedTime = currTime - startTime;
nextSleepTime = normalSleepTime
+ ((tenths * 100) - elapsedTime);
if (nextSleepTime < 0) {
nextSleepTime = 0;
}
timeText = fmt.format(elapsedTime / 1000.0);
SwingUtilities.invokeAndWait(updateText);
} catch (InterruptedException ix) {
// stop running
return;
} catch (InvocationTargetException x) {
x.printStackTrace();
}
}
}
public void stopRequest() {
noStopRequested = false;
internalThread.interrupt();
}
public boolean isAlive() {
return internalThread.isAlive();
}
public static void main(String[] args) {
JFrame f = new JFrame();
f.getContentPane().setLayout(new FlowLayout());
f.getContentPane().add(new DigitalTimer());
f.setSize(250, 100);
f.setVisible(true);
}
}