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 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package 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 46 public 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 */ lastModifiedTime()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 */ lastAccessTime()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 */ creationTime()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 */ isRegularFile()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 */ isDirectory()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 */ isSymbolicLink()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 */ isOther()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 */ size()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 */ fileKey()154 Object fileKey(); 155 } 156