Java 7 - NIO - Watcher implementation

One of the new features of Java7 was NIO package. 
Java NIO also known as new input output library as is a set of classes defined under package java.nio.* to access files, file attributes and file systems.

The main classes from this package are:

• Path - to manage file location and directory hierarchy
• Files - to manage file operations

Some functionalities that can be implemented are:

• Walking the file tree
• Watchers - monitoring the creation/modification/deletion of files
• Copy/Create/Delete files from a directory(atomic operations with synchronization)
• Find files using matcher expressions

In the following example we are going to see how to implement a watcher. This is useful when we need a process to monitor when a file is created/modified or deleted in a directory.

Steps in this example:

1- watch for new files in a directory

2- evaluate the mime type of the file

3- if it is a text file it will be copied to other directory.