Re: Chronometer

From:
rossum <rossum48@coldmail.com>
Newsgroups:
comp.lang.java.programmer
Date:
Tue, 18 Sep 2007 22:29:45 +0100
Message-ID:
<6pe0f3hke2flfi20vbidn6h2pqd0sbacp3@4ax.com>
On Tue, 18 Sep 2007 11:48:52 -0700, gaijinco <gaijinco@gmail.com>
wrote:

I suppose this is kind of an easy question but I'm getting a hard time
with it.

I want to have a loop that breaks upon a normal condition and a time-
condition namely to stop if the other condition haven't been met after
T milliseconds.

I have never used threads and to find how to do this I have read a lot
of info that doesn't seems to apply.

Thank you very much!


A simple way to do it would be using a volatile variable. You will
also need to chunk up the work you are doing so that you can check the
volatile variable from time to time. Set a second thread running that
just runs down a timer [Thread.sleep()] and changes the volatile
variable when the timer has finished.

No doubt the Java gurus can find a better way than this.

rossum

// --- Begin Code ---

public class TimedLoop {
    static volatile boolean timeRunning = true;

    static class TimeOut implements Runnable {

        private int mDelay;

        public TimeOut(int delay) {
            mDelay = delay;
        } // end constructor

        public void run() {
            try {
                Thread.sleep(mDelay);
            } catch (InterruptedException ie) { }
            // Flag end of allowed time
            timeRunning = false;
        } // end run()
    } // end class TimeOut

    public static void main(String[] args) {
        // Start timer thread
        Runnable r = new TimeOut(2000);
        Thread t = new Thread(r);
        t.start();
        
        System.out.println("Starting work loop...");
        boolean workFinished = false;
        while (timeRunning && !workFinished) {
            workFinished = doSomeStuff();
        } // end while

        if (workFinished) {
            System.out.println("Work completed.");
        } else {
            System.out.println("Loop timed out.");
        } // end if
    } // end main()

    static boolean doSomeStuff() {
        boolean workFinished;
        // Do a chunk of stuff here
        workFinished = false;
        //workFinished = true; // For testing
        return workFinished;
    } // end doSomeStuff()

} // end class TimedLoop

// --- End Code ---

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