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/**
* Interfaces and classes providing access to file and file system attributes.
*
* <blockquote><table cellspacing=1 cellpadding=0 summary="Attribute views">
* <tr><th><p align="left">Attribute views</p></th><th><p align="left">Description</p></th></tr>
* <tr><td valign=top><tt><i>{@link java.nio.file.attribute.AttributeView}</i></tt></td>
* <td>Can read or update non-opaque values associated with objects in a file system</td></tr>
* <tr><td valign=top><tt> <i>{@link java.nio.file.attribute.FileAttributeView}</i></tt></td>
* <td>Can read or update file attributes</td></tr>
* <tr><td valign=top><tt> <i>{@link java.nio.file.attribute.BasicFileAttributeView} </i></tt></td>
* <td>Can read or update a basic set of file attributes</td></tr>
* <tr><td valign=top><tt> <i>{@link java.nio.file.attribute.PosixFileAttributeView} </i></tt></td>
* <td>Can read or update POSIX defined file attributes</td></tr>
* <tr><td valign=top><tt> <i>{@link java.nio.file.attribute.DosFileAttributeView} </i></tt></td>
* <td>Can read or update FAT file attributes</td></tr>
* <tr><td valign=top><tt>  <i>{@link java.nio.file.attribute.FileOwnerAttributeView} </i></tt></td>
* <td>Can read or update the owner of a file</td></tr>
* <tr><td valign=top><tt> <i>{@link java.nio.file.attribute.AclFileAttributeView} </i></tt></td>
* <td>Can read or update Access Control Lists</td></tr>
* <tr><td valign=top><tt> <i>{@link java.nio.file.attribute.UserDefinedFileAttributeView} </i></tt></td>
* <td>Can read or update user-defined file attributes</td></tr>
* <tr><td valign=top><tt> <i>{@link java.nio.file.attribute.FileStoreAttributeView}</i></tt></td>
* <td>Can read or update file system attributes</td></tr>
* </table></blockquote>
*
* <p> An attribute view provides a read-only or updatable view of the non-opaque
* values, or <em>metadata</em>, associated with objects in a file system.
* The {@link java.nio.file.attribute.FileAttributeView} interface is
* extended by several other interfaces that that views to specific sets of file
* attributes. {@code FileAttributeViews} are selected by invoking the {@link
* java.nio.file.Files#getFileAttributeView} method with a
* <em>type-token</em> to identify the required view. Views can also be identified
* by name. The {@link java.nio.file.attribute.FileStoreAttributeView} interface
* provides access to file store attributes. A {@code FileStoreAttributeView} of
* a given type is obtained by invoking the {@link
* java.nio.file.FileStore#getFileStoreAttributeView} method.
*
* <p> The {@link java.nio.file.attribute.BasicFileAttributeView}
* class defines methods to read and update a <em>basic</em> set of file
* attributes that are common to many file systems.
*
* <p> The {@link java.nio.file.attribute.PosixFileAttributeView}
* interface extends {@code BasicFileAttributeView} by defining methods
* to access the file attributes commonly used by file systems and operating systems
* that implement the Portable Operating System Interface (POSIX) family of
* standards.
*
* <p> The {@link java.nio.file.attribute.DosFileAttributeView}
* class extends {@code BasicFileAttributeView} by defining methods to
* access the legacy "DOS" file attributes supported on file systems such as File
* Allocation Tabl (FAT), commonly used in consumer devices.
*
* <p> The {@link java.nio.file.attribute.AclFileAttributeView}
* class defines methods to read and write the Access Control List (ACL)
* file attribute. The ACL model used by this file attribute view is based
* on the model defined by <a href="http://www.ietf.org/rfc/rfc3530.txt">
* <i>RFC 3530: Network File System (NFS) version 4 Protocol</i></a>.
*
* <p> In addition to attribute views, this package also defines classes and
* interfaces that are used when accessing attributes:
*
* <ul>
*
* <p><li> The {@link java.nio.file.attribute.UserPrincipal} and
* {@link java.nio.file.attribute.GroupPrincipal} interfaces represent an
* identity or group identity. </li>
*
* <p><li> The {@link java.nio.file.attribute.UserPrincipalLookupService}
* interface defines methods to lookup user or group principals. </li>
*
* <p><li> The {@link java.nio.file.attribute.FileAttribute} interface
* represents the value of an attribute for cases where the attribute value is
* required to be set atomically when creating an object in the file system. </li>
*
* </ul>
*
*
* <p> Unless otherwise noted, passing a <tt>null</tt> argument to a constructor
* or method in any class or interface in this package will cause a {@link
* java.lang.NullPointerException NullPointerException} to be thrown.
*
* @since 1.7
*/