Problem with time displaying as 01:00:00 instead of 00:00:00

[Art Vandelay]

Hi all,

I'm having an issue with the following timer program. It is probably a silly error, but I can't see it. When the following method is called :

// used via StopWatchTimer run() to set the elapsed time on the GUI
    public void setTimerTextLabel(String s) {
        time_elapsed.setText(s);
    }

...from within the second block of code below it ends up displaying the time after 1 second as "01:00:01" instead of "00:00:01" in the GUI.

The entire code is handled by the following class:

package stopwatch;

import java.text.SimpleDateFormat;
import java.util.concurrent.TimeUnit;

/*
 * This class is responsable for maintaining the time. It implements Runnable in
 * order to calculate the time.
 */
public class StopWatchTimer implements Runnable {

    private StopWatchGUI swGui;
    private long starttime = 0;
    private long endtime = 0;
    private boolean isrunning = false;
    private long timepause = 0;
    private String timeresult;
    private long elapsed;
    private long secondspassed;

    /*
     * The constructor has a StopWatchGUI parameter. The object is used to
     * access the StopWatchGUI class in order to set the text of a label to the
     * correct time.
     */
    public StopWatchTimer(StopWatchGUI sw) {
        this.swGui = sw;
    }
    /*
     * The method run is executed when the thread is started from the
     * StopWatchGUI. It calculates the time that has spend and formats it. Then
     * it assigns the time to the label in the GUI.
     */
    @Override
    public void run() {

        try {
            while (isrunning) {
                timeresult = (formatTime(startCounting()));
                System.out.println(timeresult);
                swGui.setTimerTextLabel(timeresult);
                secondspassed = TimeUnit.SECONDS.convert(elapsed, TimeUnit.NANOSECONDS);
                swGui.setTimeRemaing(secondspassed);
                boolean played = swGui.testtimers(secondspassed);

                if (played == true) {
                    Thread.sleep(4000);
                }
            }
        } catch (Exception e) {
            e.printStackTrace(System.out);
        }
    }
    /*
     * Returns the String variable timeresult.
     */
    public String getTimeResult() {
        return timeresult;
    }

    /*
     * This method is called when you want to start the timer. This needs to be
     * called before the thread.start() is called.
     */
    public void start() {
        if (isrunning == false) {
            starttime = System.nanoTime() - (timepause - starttime);
        } else {
            starttime = System.nanoTime();
        }
        isrunning = true;
    }

    /*
     * This method is called when you want to pause the timer.
     */
    public void pause() {
        isrunning = false;
        endtime = System.nanoTime();
        timepause = System.nanoTime();
    }

    /*
     * This method is called when you want to reset the timer.
     */
    public void reset() {
        starttime = 0;
        endtime = 0;
        timepause = 0;
        isrunning = false;
    }
    /*
     * This method is called inside the run method. It returns the elapsed time.
     * If the boolean isrunning is false. Then it will return the end time.
     */
    public long startCounting() {
        
        //elapsed = 0;
        if (isrunning) {
            elapsed = System.nanoTime() - starttime;

        } else {
            elapsed = endtime - starttime;

        }
        return elapsed / 1000000;
    }

    /*
     * This method is called inside the run method. It has a parameter that
     * represents the time and reformats that time. It then returns the
     * reformatted time.
     */
    public String formatTime(long elapsedTicks) {

        SimpleDateFormat formatter = new SimpleDateFormat("HH:mm:ss");
        String time = formatter.format(elapsedTicks);
        return time;
    }
}

Any ideas?

Thanks for any help.

[jim829]

Where's the StopWatchGUI class? Where's main? The value "played?"

Jim

[Art Vandelay]

Hi Jim, as I said... the main class is only :

    public static void main(String args[]) {
        /*
         * Set the Nimbus look and feel
         */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /*
         * If Nimbus (introduced in Java SE 6) is not available, stay with the
         * default look and feel. For details see
         * http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;


                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(StopWatchGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(StopWatchGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(StopWatchGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(StopWatchGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /*
         * Create and display the form
         */
        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {

                //StopWatchGUI sw = new StopWatchGUI();
                new StopWatchGUI().setVisible(true);
            }
        });
    }

That is... the issue with the '01:00:00' appearing must be in the code already provided.

Thanks for having a look anyway.

[Art Vandelay]

I'm pretty sure now the issue is with the SimpleDateFormat adding an hour due to time zone differences, but I'm still working on it. I could simply subtract an hour before displaying, but I'd rather it be usable all year without having to change the code every 6 months due to British summer time.

[Art Vandelay]

For anyone else with the problem... it can be solved by changing to the following:

        SimpleDateFormat formatter = new SimpleDateFormat("HH:mm:ss");
        TimeZone tz = TimeZone.getTimeZone("GMT");
        formatter.setTimeZone(tz);

...the 01:00:00 now displays correctly as 00:00:00. However, I'm guessing that when BST starts I'll have to change the code.

If anyone has solved...please post here! I tried Europe/London time but that didn't work.

[Tolls]

Don't use classes designed for handling dates.
Look up Joda time if you want something that handles time periods.

Or calculate the difference yourself.

[Art Vandelay]

Hey Tolls, I agree that I should have avoided any methods that use Date-Time. However, I did not need to use Joda Time to accomplish this. All I did was delete the method

public String formatTime(long elapsedTicks) {
 
        SimpleDateFormat formatter = new SimpleDateFormat("HH:mm:ss");
        String time = formatter.format(elapsedTicks);
        return time;
    }

And replace it with a manual calculation.

    // l is in nanoseconds
    private String convertLongToString(long l) {
       
        // convert to seconds
        long m = l / 1000;
        // retrieve hours, minutes, seconds
        long hours = m / 3600;
        long minutes = (m  % 3600) / 60;
        long seconds = m  % 60;
        // and get in a string format 00:00:00
        String time = twoDigitString(hours) + ":" + twoDigitString(minutes) + ":" + twoDigitString(seconds);
        return time;
    }

    private String twoDigitString(long number) {
        if (number == 0) {
            return "00";
        }
        if (number / 10 == 0) {
            return "0" + number;
        }
        return String.valueOf(number);

Thus, my only import now is to TimeUnit.

[JosAH]

You want to display a time duration; the SimpleDateFormat tries to display an 'absolute' time, given a 'where' (a time zone) and a 'when' (daylight saving time); the two don't match.

kind regards,

Jos

[Art Vandelay]

Aye, I don't use SimpleDateFormat any more, that is the point of my previous post.