NIO.2 associates the notion of metadata with attributes and provides access to them through the
java.nio.file.attribute package. Since different file systems have different notions about which attributes should be tracked, NIO.2 groups the attributes into views, each of which maps to a particular file system implementation.
Generally, views provide the attributes in bulk through a common method,
readAttributes(). In addition, you can extract and set a single attribute with the
setAttribute() methods, respectively, which are available in the
java.nio.file.Files class. Depending On the view, other methods are available for additional tasks.
Here i will explain how with NIO.2 you can manage more details about files’ metadata than ever before. Attributes are divided into categories, and now they cover POSIX systems as well.
Before you attempt to access a view's attributes, make sure that your file system supports the corresponding view.
NIO.2 comes with a set of six views (
- POSIX (Portable Operating System Interface for UNIX).
- All file systems support the basic view, so you should get at least the basic name in your output.
The supported views are:
This is a view of basic attributes that must be supported by all file system implementations. The attribute view name is basic.
This view provides the standard four supported attributes on file systems that support the DOS attributes. The attribute view name is dos.
This view extends the basic attribute view with attributes supported on file systems that support the POSIX (Portable Operating System Interface for Unix) family of standards, such as Unix. The attribute view name is posix.
This view is supported by any file system implementation that supports the concept of a file owner. The attribute view name is owner.
This view supports reading or updating a file’s ACL. The NFSv4 ACL model is supported. The attribute view name is acl.
This view enables support of metadata that is user defined.
Here are code snipets that shows different operations
- Get all supported file system views
- Check if the file store support a specific view
You can test a particular view on a file store by calling the
FileStore.supportsFileAttributeView()method. You can pass the desired view as a String or as a class name.
- Check if a file store in which a particular file resides supports a single view
Moreover, you can check if a file store in which a particular file resides supports a single view.
That all, have fun, if you like it share it.