Windows - get warned when a file is created

Question

I'm not sure if what I'm asking is possible, but I would like to do the following: When a file is created in a certain folder (Windows), my program should respond. I'd like to let Windows call a callback method when a file is created.

Another option is of course just use a loop and constantly check if a new file is in the folder, but I'd like to know it instantly, so a callback method would be much more efficient.

Is this possible? The language is not important, although Java is preferred.

Answer 1

With Java nio 2 (available in Java 1.7 +), you can "watch" a directory and get notified when that directory changes.

The method proposed in the tutorial linked above uses the WatchService API.

Answer 2

Commons IO contains a FileAlterationListener wich has a onDirectoryChangemethod. Can be an alternative if Java 1.7 is not available.