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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 import java.io.IOException;
29 
30 /**
31  * A file attribute view that provides a view of a <em>basic set</em> of file
32  * attributes common to many file systems. The basic set of file attributes
33  * consist of <em>mandatory</em> and <em>optional</em> file attributes as
34  * defined by the {@link BasicFileAttributes} interface.
35 
36  * <p> The file attributes are retrieved from the file system as a <em>bulk
37  * operation</em> by invoking the {@link #readAttributes() readAttributes} method.
38  * This class also defines the {@link #setTimes setTimes} method to update the
39  * file's time attributes.
40  *
41  * <p> Where dynamic access to file attributes is required, the attributes
42  * supported by this attribute view have the following names and types:
43  * <blockquote>
44  *  <table border="1" cellpadding="8" summary="Supported attributes">
45  *   <tr>
46  *     <th> Name </th>
47  *     <th> Type </th>
48  *   </tr>
49  *  <tr>
50  *     <td> "lastModifiedTime" </td>
51  *     <td> {@link FileTime} </td>
52  *   </tr>
53  *   <tr>
54  *     <td> "lastAccessTime" </td>
55  *     <td> {@link FileTime} </td>
56  *   </tr>
57  *   <tr>
58  *     <td> "creationTime" </td>
59  *     <td> {@link FileTime} </td>
60  *   </tr>
61  *   <tr>
62  *     <td> "size" </td>
63  *     <td> {@link Long} </td>
64  *   </tr>
65  *   <tr>
66  *     <td> "isRegularFile" </td>
67  *     <td> {@link Boolean} </td>
68  *   </tr>
69  *   <tr>
70  *     <td> "isDirectory" </td>
71  *     <td> {@link Boolean} </td>
72  *   </tr>
73  *   <tr>
74  *     <td> "isSymbolicLink" </td>
75  *     <td> {@link Boolean} </td>
76  *   </tr>
77  *   <tr>
78  *     <td> "isOther" </td>
79  *     <td> {@link Boolean} </td>
80  *   </tr>
81  *   <tr>
82  *     <td> "fileKey" </td>
83  *     <td> {@link Object} </td>
84  *   </tr>
85  * </table>
86  * </blockquote>
87  *
88  * <p> The {@link java.nio.file.Files#getAttribute getAttribute} method may be
89  * used to read any of these attributes as if by invoking the {@link
90  * #readAttributes() readAttributes()} method.
91  *
92  * <p> The {@link java.nio.file.Files#setAttribute setAttribute} method may be
93  * used to update the file's last modified time, last access time or create time
94  * attributes as if by invoking the {@link #setTimes setTimes} method.
95  *
96  * @since 1.7
97  */
98 
99 public interface BasicFileAttributeView
100     extends FileAttributeView
101 {
102     /**
103      * Returns the name of the attribute view. Attribute views of this type
104      * have the name {@code "basic"}.
105      */
106     @Override
name()107     String name();
108 
109     /**
110      * Reads the basic file attributes as a bulk operation.
111      *
112      * <p> It is implementation specific if all file attributes are read as an
113      * atomic operation with respect to other file system operations.
114      *
115      * @return  the file attributes
116      *
117      * @throws  IOException
118      *          if an I/O error occurs
119      * @throws  SecurityException
120      *          In the case of the default provider, a security manager is
121      *          installed, its {@link SecurityManager#checkRead(String) checkRead}
122      *          method is invoked to check read access to the file
123      */
readAttributes()124     BasicFileAttributes readAttributes() throws IOException;
125 
126     /**
127      * Updates any or all of the file's last modified time, last access time,
128      * and create time attributes.
129      *
130      * <p> This method updates the file's timestamp attributes. The values are
131      * converted to the epoch and precision supported by the file system.
132      * Converting from finer to coarser granularities result in precision loss.
133      * The behavior of this method when attempting to set a timestamp that is
134      * not supported or to a value that is outside the range supported by the
135      * underlying file store is not defined. It may or not fail by throwing an
136      * {@code IOException}.
137      *
138      * <p> If any of the {@code lastModifiedTime}, {@code lastAccessTime},
139      * or {@code createTime} parameters has the value {@code null} then the
140      * corresponding timestamp is not changed. An implementation may require to
141      * read the existing values of the file attributes when only some, but not
142      * all, of the timestamp attributes are updated. Consequently, this method
143      * may not be an atomic operation with respect to other file system
144      * operations. Reading and re-writing existing values may also result in
145      * precision loss. If all of the {@code lastModifiedTime}, {@code
146      * lastAccessTime} and {@code createTime} parameters are {@code null} then
147      * this method has no effect.
148      *
149      * <p> <b>Usage Example:</b>
150      * Suppose we want to change a file's last access time.
151      * <pre>
152      *    Path path = ...
153      *    FileTime time = ...
154      *    Files.getFileAttributeView(path, BasicFileAttributeView.class).setTimes(null, time, null);
155      * </pre>
156      *
157      * @param   lastModifiedTime
158      *          the new last modified time, or {@code null} to not change the
159      *          value
160      * @param   lastAccessTime
161      *          the last access time, or {@code null} to not change the value
162      * @param   createTime
163      *          the file's create time, or {@code null} to not change the value
164      *
165      * @throws  IOException
166      *          if an I/O error occurs
167      * @throws  SecurityException
168      *          In the case of the default provider, a security manager is
169      *          installed, its  {@link SecurityManager#checkWrite(String) checkWrite}
170      *          method is invoked to check write access to the file
171      *
172      * @see java.nio.file.Files#setLastModifiedTime
173      */
setTimes(FileTime lastModifiedTime, FileTime lastAccessTime, FileTime createTime)174     void setTimes(FileTime lastModifiedTime,
175                   FileTime lastAccessTime,
176                   FileTime createTime) throws IOException;
177 }
178