Java Coding Problems

135. Watching paths

Watching paths for changes is just one of the thread-safe goals that can be accomplished via the JDK 7 NIO.2, low-level WatchService API.

In a nutshell, a path can be watched for changes by following two major steps:

1. Register a folder (or folders) to be watched for different kinds of event types.
2. When a registered event type is detected by WatchService, it is handled in a separate thread, so the watch service is not blocked.

At the API level, the starting point is the WatchService interface. This interface comes in different flavors for different file/operating systems.

This interface works hand-in-hand with two main classes. Together, they provide a convenient approach that you can implement to add watching capabilities ...