How to use timer to monitor lengthy loop progress

Hi,

I have a long process that iterates through a large data set and I need to monitor its progress.

Right now it's something like:

Read recordSet
for (...index++) {
... process record[index];
if (index modulus 500 = 0) {log to stdout}
}

I'm using stdout since that's where the output from the Garbage Collector is gathered, so I can check how the loop is behaving memory-wise.

In other languages I'd use a timer instead of the ugly 'if (...' but I am quite new and lost in Java, and I have been unable to find any suitable examples.

How can I use a timer in this context so that the logging is triggered each 30s, for instance? The loop might run for a veeery long time (20-60 minutes).

I understand that this would require (at least!):
- Setting up the timer
- Starting the loop
- Getting some info about the loop status, in the timer callback
- Shutting down/Killing the timer when the loop ends (or fails...)

Can anyone help?

Thanks to all.

You can use Swing timer as well for this, with a thread.

Thanks Eranga!

I guess that I did not provide enough information about the setup of my app. Sorry for that!

These processes are run in a server (no GUI is involved). They are automated queries to a rather large database about books and the result of each one is a file (in the order of 50-100MB) which is sent back to the corresponding user via ftp.

Several such loops might be running simultaneously, each in its own thread.

Would Swing be a good choice for such a setup?

Thanks again!

Swing timers would be fine. Either the Swing Timer or the Utility Timer (javax.swing.Timer and java.util.Timer) would work. If all you are doing is logging data to a stream, you should be fine with either, but if you have lengthy actions after the timer completes, the Utility Timer would probably be better.

Good Luck with whatever you choose,
Singing Boyo

EDIT: Did another quick read of your original post. If you want to log data every 30 times it loops, That would probably have to be done differently.

You can use system time to find out your loop process execution

Quote:

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Originally Posted by JotaPe

These processes are run in a server (no GUI is involved).

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Actually event without involve of UI you can use swing timer. You have to design that. Just look at the following example.

Code:

---

import java.awt.event.*;
import javax.swing.Timer;

/**
 *
 * @author Eranga Thennakoon
 */
public class SwingTimerDemo {

    /**
    * @param args the command line arguments
    */
    public static void main(String[] args) {
        // Initialize the timer object, in interval of 1 second
        Timer MyTimer = new Timer(1000, new MyTimerActionListener());

        // Start the timer
        MyTimer.start();

        // Keep the main thread qite for 10 seconds
        try {
        Thread.sleep(10000);
        }
        catch (InterruptedException ex) {
            ex.printStackTrace();
        }

        // Stop the timer at the end
        MyTimer.stop();
    }
}

class MyTimerActionListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        System.out.println("Swing Timer");
    }
}

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I think you can understand the above code, if not let me know. I'll explain it again.

Ya I think it's the best way you have to take.

Quote:

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Originally Posted by JotaPe

Several such loops might be running simultaneously, each in its own thread.

---

You mean that, you have separate thread for each loop?

Quote:

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Originally Posted by makpandian

You can use system time to find out your loop process execution

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But I think he wants to find the time interval. Still you want a way to tick the time.