/*

 * Copyright 2007-2009 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package java.nio.file.attribute;

import java.nio.file.*;

import java.io.IOException;

import java.util.*;

/**

 * This class consists exclusively of static methods that operate on or return

 * the attributes of files or file stores. These methods provide for convenient

 * use of the {@link AttributeView attribute-views} defined in this package.

 *

 * @since 1.7

 */

public final class Attributes {

    /**

     * Reads the basic file attributes of a file.

     *

     * <p> The {@code options} array may be used to indicate how symbolic links

     * are handled for the case that the file is a symbolic link. By default,

     * symbolic links are followed and the file attributes of the final target

     * of the link are read. If the option {@link LinkOption#NOFOLLOW_LINKS

     * NOFOLLOW_LINKS} is present then symbolic links are not followed and so

     * the method returns the file attributes of the symbolic link. This option

     * should be used where there is a need to determine if a file is a

     * symbolic link:

     * <pre>

     *    boolean isSymbolicLink = Attributes.readBasicFileAttributes(file, NOFOLLOW_LINKS).isSymbolicLink();

     * </pre>

     *

     * <p> It is implementation specific if all file attributes are read as an

     * atomic operation with respect to other file system operations.

     *

     * @param   file

     *          A file reference that locates the file

     * @param   options

     *          Options indicating how symbolic links are handled

     *

     * @return  The basic file attributes

     *

     * @throws  IOException

     *          If an I/O error occurs

     * @throws  SecurityException

     *          In the case of the default provider, the security manager's {@link

     *          SecurityManager#checkRead(String) checkRead} method is invoked

     *          to check read access to file

     *

     * @see BasicFileAttributeView#readAttributes

     */

    public static BasicFileAttributes readBasicFileAttributes(FileRef file,

                                                              LinkOption... options)

        throws IOException

    {

        return file.getFileAttributeView(BasicFileAttributeView.class, options)

            .readAttributes();

    }

    /**

     * Reads the POSIX file attributes of a file.

     *

     * <p> The {@code file} parameter locates a file that supports the {@link

     * PosixFileAttributeView}. This file attribute view provides access to a

     * subset of the file attributes commonly associated with files on file

     * systems used by operating systems that implement the Portable Operating

     * System Interface (POSIX) family of standards. It is implementation

     * specific if all file attributes are read as an atomic operation with

     * respect to other file system operations.

     *

     * <p> The {@code options} array may be used to indicate how symbolic links

     * are handled for the case that the file is a symbolic link. By default,

     * symbolic links are followed and the file attributes of the final target

     * of the link are read. If the option {@link LinkOption#NOFOLLOW_LINKS

     * NOFOLLOW_LINKS} is present then symbolic links are not followed and so

     * the method returns the file attributes of the symbolic link.

     *

     * @param   file

     *          A file reference that locates the file

     * @param   options

     *          Options indicating how symbolic links are handled

     *

     * @return  The POSIX file attributes

     *

     * @throws  UnsupportedOperationException

     *          If the {@code PosixFileAttributeView} is not available

     * @throws  IOException

     *          If an I/O error occurs

     * @throws  SecurityException

     *          In the case of the default provider, and a security manager is

     *          installed, it denies {@link RuntimePermission}<tt>("accessUserInformation")</tt>

     *          or its {@link SecurityManager#checkRead(String) checkRead} method

     *          denies read access to the file.

     *

     * @see PosixFileAttributeView#readAttributes

     */

    public static PosixFileAttributes readPosixFileAttributes(FileRef file,

                                                              LinkOption... options)

        throws IOException

    {

        PosixFileAttributeView view =

            file.getFileAttributeView(PosixFileAttributeView.class, options);

        if (view == null)

            throw new UnsupportedOperationException();

        return view.readAttributes();

    }

    /**

     * Reads the DOS file attributes of a file.

     *

     * <p> The {@code file} parameter locates a file that supports the {@link

     * DosFileAttributeView}. This file attribute view provides access to

     * legacy "DOS" attributes supported by the file systems such as File

     * Allocation Table (FAT), commonly used in <em>consumer devices</em>. It is

     * implementation specific if all file attributes are read as an atomic

     * operation with respect to other file system operations.

     *

     * <p> The {@code options} array may be used to indicate how symbolic links

     * are handled for the case that the file is a symbolic link. By default,

     * symbolic links are followed and the file attributes of the final target

     * of the link are read. If the option {@link LinkOption#NOFOLLOW_LINKS

     * NOFOLLOW_LINKS} is present then symbolic links are not followed and so

     * the method returns the file attributes of the symbolic link.

     *

     * @param   file

     *          A file reference that locates the file

     * @param   options

     *          Options indicating how symbolic links are handled

     *

     * @return  The DOS file attributes

     *

     * @throws  UnsupportedOperationException

     *          If the {@code DosFileAttributeView} is not available

     * @throws  IOException

     *          If an I/O error occurs

     * @throws  SecurityException

     *          In the case of the default provider, the security manager's {@link

     *          SecurityManager#checkRead(String) checkRead} method is invoked

     *          to check read access to file

     *

     * @see DosFileAttributeView#readAttributes

     */

    public static DosFileAttributes readDosFileAttributes(FileRef file,

                                                          LinkOption... options)

        throws IOException

    {

        DosFileAttributeView view =

            file.getFileAttributeView(DosFileAttributeView.class, options);

        if (view == null)

            throw new UnsupportedOperationException();

        return view.readAttributes();

    }

    /**

     * Returns the owner of a file.

     *

     * <p> The {@code file} parameter locates a file that supports the {@link

     * FileOwnerAttributeView}. This file attribute view provides access to

     * a file attribute that is the owner of the file.

     *

     * @param   file

     *          A file reference that locates the file

     *

     * @return  A user principal representing the owner of the file

     *

     * @throws  UnsupportedOperationException

     *          If the {@code FileOwnerAttributeView} is not available

     * @throws  IOException

     *          If an I/O error occurs

     * @throws  SecurityException

     *          In the case of the default provider, and a security manager is

     *          installed, it denies {@link RuntimePermission}<tt>("accessUserInformation")</tt>

     *          or its {@link SecurityManager#checkRead(String) checkRead} method

     *          denies read access to the file.

     *

     * @see FileOwnerAttributeView#getOwner

     */

    public static UserPrincipal getOwner(FileRef file) throws IOException {

        FileOwnerAttributeView view =

            file.getFileAttributeView(FileOwnerAttributeView.class);

        if (view == null)

            throw new UnsupportedOperationException();

        return view.getOwner();

    }

    /**

     * Updates the file owner.

     *

     * <p> The {@code file} parameter locates a file that supports the {@link

     * FileOwnerAttributeView}. This file attribute view provides access to

     * a file attribute that is the owner of the file.

     *

     * @param   file

     *          A file reference that locates the file

     * @param   owner

     *          The new file owner

     *

     * @throws  UnsupportedOperationException

     *          If the {@code FileOwnerAttributeView} is not available

     * @throws  IOException

     *          If an I/O error occurs

     * @throws  SecurityException

     *          In the case of the default provider, and a security manager is

     *          installed, it denies {@link RuntimePermission}<tt>("accessUserInformation")</tt>

     *          or its {@link SecurityManager#checkWrite(String) checkWrite}

     *          method denies write access to the file.

     *

     * @see FileOwnerAttributeView#setOwner

     */

    public static void setOwner(FileRef file, UserPrincipal owner)

            throws IOException

    {

        FileOwnerAttributeView view =

            file.getFileAttributeView(FileOwnerAttributeView.class);

        if (view == null)

            throw new UnsupportedOperationException();

        view.setOwner(owner);

    }

    /**

     * Reads a file's Access Control List (ACL).

     *

     * <p> The {@code file} parameter locates a file that supports the {@link

     * AclFileAttributeView}. This file attribute view provides access to ACLs

     * based on the ACL model specified in

     *  <a href="http://www.ietf.org/rfc/rfc3530.txt"><i>RFC&nbsp;3530</i></a>.

     *

     * @param   file

     *          A file reference that locates the file

     *

     * @return  An ordered list of {@link AclEntry entries} representing the

     *          ACL. The returned list is modifiable.

     *

     * @throws  UnsupportedOperationException

     *          If the {@code AclAttributeView} is not available

     * @throws  IOException

     *          If an I/O error occurs

     * @throws  SecurityException

     *          In the case of the default provider, and a security manager is

     *          installed, it denies {@link RuntimePermission}<tt>("accessUserInformation")</tt>

     *          or its {@link SecurityManager#checkRead(String) checkRead} method

     *          denies read access to the file.

     *

     * @see AclFileAttributeView#getAcl

     */

    public static List<AclEntry> getAcl(FileRef file) throws IOException {

        AclFileAttributeView view =

            file.getFileAttributeView(AclFileAttributeView.class);

        if (view == null)

            throw new UnsupportedOperationException();

        return view.getAcl();

    }

    /**

     * Updates a file's Access Control List (ACL).

     *

     * <p> The {@code file} parameter locates a file that supports the {@link

     * AclFileAttributeView}. This file attribute view provides access to ACLs

     * based on the ACL model specified in

     *  <a href="http://www.ietf.org/rfc/rfc3530.txt"><i>RFC&nbsp;3530</i></a>.

     *

     * @param   file

     *          A file reference that locates the file

     * @param   acl

     *          The new file ACL

     *

     * @throws  UnsupportedOperationException

     *          If the {@code AclFileAttributeView} is not available

     * @throws  IOException

     *          If an I/O error occurs

     * @throws  SecurityException

     *          In the case of the default provider, and a security manager is

     *          installed, it denies {@link RuntimePermission}<tt>("accessUserInformation")</tt>

     *          or its {@link SecurityManager#checkWrite(String) checkWrite}

     *          method denies write access to the file.

     *

     * @see AclFileAttributeView#setAcl

     */

    public static void setAcl(FileRef file, List<AclEntry> acl)

        throws IOException

    {

        AclFileAttributeView view =

            file.getFileAttributeView(AclFileAttributeView.class);

        if (view == null)

            throw new UnsupportedOperationException();

        view.setAcl(acl);

    }

    /**

     *

     *

     *

     * @param   file

     *          A file reference that locates the file

     *

     * @throws  IOException

     *          If an I/O error occurs

     * @throws  SecurityException

     *          In the case of the default provider, the security manager's {@link

     *          SecurityManager#checkWrite(String) checkWrite} method is invoked

     *          to check write access to file

     *

     * @see BasicFileAttributeView#setTimes

     */

    public static void setLastModifiedTime(FileRef file,

        throws IOException

    {

        file.getFileAttributeView(BasicFileAttributeView.class)

    }

    /**

     *

     * <p> If the file system does not support a last access time attribute then

     * this method has no effect.

     *

     * @param   lastAccessTime

     *

     * @throws  IOException

     *          If an I/O error occurs

     * @throws  SecurityException

     *          In the case of the default provider, the security manager's {@link

     *          SecurityManager#checkWrite(String) checkWrite} method is invoked

     *          to check write access to file

     *

     * @see BasicFileAttributeView#setTimes

     */

    public static void setLastAccessTime(FileRef file,

        throws IOException

    {

        file.getFileAttributeView(BasicFileAttributeView.class)

    }

    /**

     * Sets a file's POSIX permissions.

     *

     * <p> The {@code file} parameter is a reference to an existing file. It

     * supports the {@link PosixFileAttributeView} that provides access to file

     * attributes commonly associated with files on file systems used by

     * operating systems that implement the Portable Operating System Interface

     * (POSIX) family of standards.

     *

     * @param   file

     *          A file reference that locates the file

     * @param   perms

     *          The new set of permissions

     *

     * @throws  UnsupportedOperationException

     *          If {@code PosixFileAttributeView} is not available

     * @throws  ClassCastException

     *          If the sets contains elements that are not of type {@code

     *          PosixFilePermission}

     * @throws  IOException

     *          If an I/O error occurs

     * @throws  SecurityException

     *          In the case of the default provider, and a security manager is

     *          installed, it denies {@link RuntimePermission}<tt>("accessUserInformation")</tt>

     *          or its {@link SecurityManager#checkWrite(String) checkWrite}

     *          method denies write access to the file.

     *

     * @see PosixFileAttributeView#setPermissions

     */

    public static void setPosixFilePermissions(FileRef file,

                                               Set<PosixFilePermission> perms)

        throws IOException

    {

        PosixFileAttributeView view =

            file.getFileAttributeView(PosixFileAttributeView.class);

        if (view == null)

            throw new UnsupportedOperationException();

        view.setPermissions(perms);

    }

    /**

     * Reads the space attributes of a file store.

     *

     * <p> The {@code store} parameter is a file store that supports the

     * {@link FileStoreSpaceAttributeView} providing access to the space related

     * attributes of the file store. It is implementation specific if all attributes

     * are read as an atomic operation with respect to other file system operations.

     *

     * @param   store

     *          The file store

     *

     * @return  The file store space attributes

     *

     * @throws  UnsupportedOperationException

     *          If the file store space attribute view is not supported

     * @throws  IOException

     *          If an I/O error occurs

     *

     * @see FileStoreSpaceAttributeView#readAttributes()

     */

    public static FileStoreSpaceAttributes readFileStoreSpaceAttributes(FileStore store)

        throws IOException

    {

        FileStoreSpaceAttributeView view =

            store.getFileStoreAttributeView(FileStoreSpaceAttributeView.class);

        if (view == null)

            throw new UnsupportedOperationException();

        return view.readAttributes();

    }

}