Java tutorial
/* * Copyright (c) 2007, 2013, Oracle and/or its affiliates. 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. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.nio.file.attribute; /** * Basic attributes associated with a file in a file system. * * <p> Basic file attributes are attributes that are common to many file systems * and consist of mandatory and optional file attributes as defined by this * interface. * * <p> <b>Usage Example:</b> * <pre> * Path file = ... * BasicFileAttributes attrs = Files.readAttributes(file, BasicFileAttributes.class); * </pre> * * @since 1.7 * * @see BasicFileAttributeView */ public interface BasicFileAttributes { /** * Returns the time of last modification. * * <p> If the file system implementation does not support a time stamp * to indicate the time of last modification then this method returns an * implementation specific default value, typically a {@code FileTime} * representing the epoch (1970-01-01T00:00:00Z). * * @return a {@code FileTime} representing the time the file was last * modified */ FileTime lastModifiedTime(); /** * Returns the time of last access. * * <p> If the file system implementation does not support a time stamp * to indicate the time of last access then this method returns * an implementation specific default value, typically the {@link * #lastModifiedTime() last-modified-time} or a {@code FileTime} * representing the epoch (1970-01-01T00:00:00Z). * * @return a {@code FileTime} representing the time of last access */ FileTime lastAccessTime(); /** * Returns the creation time. The creation time is the time that the file * was created. * * <p> If the file system implementation does not support a time stamp * to indicate the time when the file was created then this method returns * an implementation specific default value, typically the {@link * #lastModifiedTime() last-modified-time} or a {@code FileTime} * representing the epoch (1970-01-01T00:00:00Z). * * @return a {@code FileTime} representing the time the file was created */ FileTime creationTime(); /** * Tells whether the file is a regular file with opaque content. * * @return {@code true} if the file is a regular file with opaque content */ boolean isRegularFile(); /** * Tells whether the file is a directory. * * @return {@code true} if the file is a directory */ boolean isDirectory(); /** * Tells whether the file is a symbolic link. * * @return {@code true} if the file is a symbolic link */ boolean isSymbolicLink(); /** * Tells whether the file is something other than a regular file, directory, * or symbolic link. * * @return {@code true} if the file something other than a regular file, * directory or symbolic link */ boolean isOther(); /** * Returns the size of the file (in bytes). The size may differ from the * actual size on the file system due to compression, support for sparse * files, or other reasons. The size of files that are not {@link * #isRegularFile regular} files is implementation specific and * therefore unspecified. * * @return the file size, in bytes */ long size(); /** * Returns an object that uniquely identifies the given file, or {@code * null} if a file key is not available. On some platforms or file systems * it is possible to use an identifier, or a combination of identifiers to * uniquely identify a file. Such identifiers are important for operations * such as file tree traversal in file systems that support <a * href="../package-summary.html#links">symbolic links</a> or file systems * that allow a file to be an entry in more than one directory. On UNIX file * systems, for example, the <em>device ID</em> and <em>inode</em> are * commonly used for such purposes. * * <p> The file key returned by this method can only be guaranteed to be * unique if the file system and files remain static. Whether a file system * re-uses identifiers after a file is deleted is implementation dependent and * therefore unspecified. * * <p> File keys returned by this method can be compared for equality and are * suitable for use in collections. If the file system and files remain static, * and two files are the {@link java.nio.file.Files#isSameFile same} with * non-{@code null} file keys, then their file keys are equal. * * @return an object that uniquely identifies the given file, or {@code null} * * @see java.nio.file.Files#walkFileTree */ Object fileKey(); }