Java 7 WatchService - Ignoring multiple occurrences of the same event

Question

The javadoc for StandardWatchEventKinds.ENTRY_MODIFY says:

Directory entry modified. When a directory is registered for this event the

Answer 1

I compiled Oracle's WatchDir.java and @nilesh's suggestion into an Observable class that will notify it's observers once when the watched file is changed.

I tried to make it as readable and short as possible, but still landed with more than 100 lines. Improvements welcome, of course.

Usage:

FileChangeNotifier fileReloader = new FileChangeNotifier(File file);
fileReloader.addObserver((Observable obj, Object arg) -> {
    System.out.println("File changed for the " + arg + " time.");
});

See my solution on GitHub: FileChangeNotifier.java.