Re: TimerTask as Filewatcher.

From:

Daniel Pitts <newsgroup.spamfilter@virtualinfinity.net>

Newsgroups:

comp.lang.java.programmer

Date:

Thu, 01 Nov 2007 18:09:37 -0700

Message-ID:

<2PKdnRNlc7Jw5bfanZ2dnUVZ_h2pnZ2d@wavecable.com>

Lew wrote:

smartnhandsome wrote:

I want to use TimerTask to watch for a file in a particular folder.
and proceed to another line of code only after i get the file in a
particular folder.

Knute Johnson wrote:

import java.io.*;
import java.util.*;

public class test {
    public static void main(String[] args) {
        Timer timer = new Timer();
        TimerTask task = new TimerTask() {
            public void run() {
                File f = new File("c://temp3//");
                if (f.exists()) {
                    cancel(); // so it doesn't do it again
                    // do your thing here
                }
            }
        };
        timer.schedule(task,1000,1000); // try every second
    }
}

Now, finding out if that file not only exists but is complete, that's
another issue. You could find the file and another process might still
be writing to it.

Generally, most OSes have a way to rename a file as an atomic operation.
Doing this allows you to create the file under a different name, fill
it appropriately, and then rename it to what its supposed to. Barring
that, you should obtain a lock on the file (not sure Java supports that).

--
Daniel Pitts' Tech Blog: <http://virtualinfinity.net/wordpress/>