1/*
2 * Copyright (c) 2007, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 * questions.
24 */
25
26package java.nio.file.attribute;
27
28/**
29 * Basic attributes associated with a file in a file system.
30 *
31 * <p> Basic file attributes are attributes that are common to many file systems
32 * and consist of mandatory and optional file attributes as defined by this
33 * interface.
34 *
35 * <p> <b>Usage Example:</b>
36 * <pre>
37 *    Path file = ...
38 *    BasicFileAttributes attrs = Files.readAttributes(file, BasicFileAttributes.class);
39 * </pre>
40 *
41 * @since 1.7
42 *
43 * @see BasicFileAttributeView
44 */
45
46public interface BasicFileAttributes {
47
48    /**
49     * Returns the time of last modification.
50     *
51     * <p> If the file system implementation does not support a time stamp
52     * to indicate the time of last modification then this method returns an
53     * implementation specific default value, typically a {@code FileTime}
54     * representing the epoch (1970-01-01T00:00:00Z).
55     *
56     * @return  a {@code FileTime} representing the time the file was last
57     *          modified
58     */
59    FileTime lastModifiedTime();
60
61    /**
62     * Returns the time of last access.
63     *
64     * <p> If the file system implementation does not support a time stamp
65     * to indicate the time of last access then this method returns
66     * an implementation specific default value, typically the {@link
67     * #lastModifiedTime() last-modified-time} or a {@code FileTime}
68     * representing the epoch (1970-01-01T00:00:00Z).
69     *
70     * @return  a {@code FileTime} representing the time of last access
71     */
72    FileTime lastAccessTime();
73
74    /**
75     * Returns the creation time. The creation time is the time that the file
76     * was created.
77     *
78     * <p> If the file system implementation does not support a time stamp
79     * to indicate the time when the file was created then this method returns
80     * an implementation specific default value, typically the {@link
81     * #lastModifiedTime() last-modified-time} or a {@code FileTime}
82     * representing the epoch (1970-01-01T00:00:00Z).
83     *
84     * @return   a {@code FileTime} representing the time the file was created
85     */
86    FileTime creationTime();
87
88    /**
89     * Tells whether the file is a regular file with opaque content.
90     *
91     * @return {@code true} if the file is a regular file with opaque content
92     */
93    boolean isRegularFile();
94
95    /**
96     * Tells whether the file is a directory.
97     *
98     * @return {@code true} if the file is a directory
99     */
100    boolean isDirectory();
101
102    /**
103     * Tells whether the file is a symbolic link.
104     *
105     * @return {@code true} if the file is a symbolic link
106     */
107    boolean isSymbolicLink();
108
109    /**
110     * Tells whether the file is something other than a regular file, directory,
111     * or symbolic link.
112     *
113     * @return {@code true} if the file something other than a regular file,
114     *         directory or symbolic link
115     */
116    boolean isOther();
117
118    /**
119     * Returns the size of the file (in bytes). The size may differ from the
120     * actual size on the file system due to compression, support for sparse
121     * files, or other reasons. The size of files that are not {@link
122     * #isRegularFile regular} files is implementation specific and
123     * therefore unspecified.
124     *
125     * @return  the file size, in bytes
126     */
127    long size();
128
129    /**
130     * Returns an object that uniquely identifies the given file, or {@code
131     * null} if a file key is not available. On some platforms or file systems
132     * it is possible to use an identifier, or a combination of identifiers to
133     * uniquely identify a file. Such identifiers are important for operations
134     * such as file tree traversal in file systems that support <a
135     * href="../package-summary.html#links">symbolic links</a> or file systems
136     * that allow a file to be an entry in more than one directory. On UNIX file
137     * systems, for example, the <em>device ID</em> and <em>inode</em> are
138     * commonly used for such purposes.
139     *
140     * <p> The file key returned by this method can only be guaranteed to be
141     * unique if the file system and files remain static. Whether a file system
142     * re-uses identifiers after a file is deleted is implementation dependent and
143     * therefore unspecified.
144     *
145     * <p> File keys returned by this method can be compared for equality and are
146     * suitable for use in collections. If the file system and files remain static,
147     * and two files are the {@link java.nio.file.Files#isSameFile same} with
148     * non-{@code null} file keys, then their file keys are equal.
149     *
150     * @return an object that uniquely identifies the given file, or {@code null}
151     *
152     * @see java.nio.file.Files#walkFileTree
153     */
154    Object fileKey();
155}
156