Executing a fn every hour

[David Duran]

I want to run a java program that calls a function defined in it's class every hour. I've never done such a thing (only META refresh in HTML, hahaha).
Could anyone point me how to do this? I would run the java program from the command line and the logic to do the calling would reside in the main().

[Marilyn de Queiroz]

Here's a suggestion:

while ( true )
{
    // call function() here
    try
    {
        // 1000 millis/second * 60 seconds/minute * 60 minutes/hour
        sleep ( 60 * 60 * 1000 )
        // call function()
    }
    catch ( InterruptedException ie )
    {
        System.out.println( "caught InterruptedException " + ie )
    }
}  

I would recommend starting a separate thread rather than keeping everything in main().

[David Duran]

Thanks Marilyn!
Clarification: Is it necessary to call the function before the try {...} block? Is the difference simply:
function() ... 1 hour ... function() versus
...1 hour... function()?

[Matt Siegel]

Check out the java.util.Timer and the corresponding java.util.TimerTask classes. They will do exactly what you want.
HTH,
Matt

[Marilyn de Queiroz]

Originally posted by David Duran:
Clarification: Is it necessary to call the function before the try {...} block? Is the difference simply:
function() ... 1 hour ... function() versus
...1 hour... function()?

Yes. That's the only difference.

[David Duran]

Thanks Matt, the Timer class looks like it would do the job but this code is going into an RMI server app which already extends UnicastRemoteObject. Since Timer requires a TimerTask object as one of the parameters to it's schedule functions that would mean I'd have to extend TimerTask (since it's abstract) within this class.
Since I can't extend 2 classes I guess I can't use TimerTask and Timer (unless I'm mistaken). Right now I'm able to implement threads because I'm implementing Runnable as opposed to extending Thread.

[karl koch]

hi,
try javax.swing.Timer
it takes an actionListener so no need to extend, jsut implement the interface.
k