1 /* |
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2 * Copyright (c) 2007, 2009, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. Oracle designates this |
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8 * particular file as subject to the "Classpath" exception as provided |
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9 * by Oracle in the LICENSE file that accompanied this code. |
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10 * |
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11 * This code is distributed in the hope that it will be useful, but WITHOUT |
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12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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14 * version 2 for more details (a copy is included in the LICENSE file that |
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15 * accompanied this code). |
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16 * |
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17 * You should have received a copy of the GNU General Public License version |
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18 * 2 along with this work; if not, write to the Free Software Foundation, |
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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20 * |
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21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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22 * or visit www.oracle.com if you need additional information or have any |
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23 * questions. |
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24 */ |
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25 |
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26 package java.nio.file.attribute; |
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27 |
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28 import java.nio.file.*; |
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29 import java.io.IOException; |
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30 import java.util.*; |
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31 |
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32 /** |
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33 * This class consists exclusively of static methods that operate on or return |
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34 * the attributes of files or file stores. These methods provide for convenient |
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35 * use of the {@link AttributeView attribute-views} defined in this package. |
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36 * |
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37 * @since 1.7 |
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38 */ |
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39 |
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40 public final class Attributes { |
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41 private Attributes() { } |
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42 |
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43 /** |
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44 * Reads the basic file attributes of a file. |
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45 * |
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46 * <p> The {@code options} array may be used to indicate how symbolic links |
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47 * are handled for the case that the file is a symbolic link. By default, |
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48 * symbolic links are followed and the file attributes of the final target |
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49 * of the link are read. If the option {@link LinkOption#NOFOLLOW_LINKS |
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50 * NOFOLLOW_LINKS} is present then symbolic links are not followed and so |
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51 * the method returns the file attributes of the symbolic link itself. |
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52 * This option should be used where there is a need to determine if a |
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53 * file is a symbolic link: |
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54 * <pre> |
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55 * boolean isSymbolicLink = Attributes.readBasicFileAttributes(file, NOFOLLOW_LINKS).isSymbolicLink(); |
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56 * </pre> |
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57 * |
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58 * <p> It is implementation specific if all file attributes are read as an |
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59 * atomic operation with respect to other file system operations. |
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60 * |
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61 * @param file |
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62 * A file reference that locates the file |
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63 * @param options |
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64 * Options indicating how symbolic links are handled |
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65 * |
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66 * @return The basic file attributes |
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67 * |
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68 * @throws IOException |
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69 * If an I/O error occurs |
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70 * @throws SecurityException |
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71 * In the case of the default provider, the security manager's {@link |
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72 * SecurityManager#checkRead(String) checkRead} method is invoked |
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73 * to check read access to file |
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74 * |
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75 * @see BasicFileAttributeView#readAttributes |
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76 */ |
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77 public static BasicFileAttributes readBasicFileAttributes(FileRef file, |
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78 LinkOption... options) |
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79 throws IOException |
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80 { |
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81 return file.getFileAttributeView(BasicFileAttributeView.class, options) |
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82 .readAttributes(); |
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83 } |
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84 |
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85 /** |
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86 * Reads the POSIX file attributes of a file. |
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87 * |
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88 * <p> The {@code file} parameter locates a file that supports the {@link |
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89 * PosixFileAttributeView}. This file attribute view provides access to a |
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90 * subset of the file attributes commonly associated with files on file |
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91 * systems used by operating systems that implement the Portable Operating |
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92 * System Interface (POSIX) family of standards. It is implementation |
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93 * specific if all file attributes are read as an atomic operation with |
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94 * respect to other file system operations. |
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95 * |
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96 * <p> The {@code options} array may be used to indicate how symbolic links |
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97 * are handled for the case that the file is a symbolic link. By default, |
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98 * symbolic links are followed and the file attributes of the final target |
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99 * of the link are read. If the option {@link LinkOption#NOFOLLOW_LINKS |
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100 * NOFOLLOW_LINKS} is present then symbolic links are not followed and so |
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101 * the method returns the file attributes of the symbolic link itself. |
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102 * |
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103 * @param file |
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104 * A file reference that locates the file |
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105 * @param options |
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106 * Options indicating how symbolic links are handled |
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107 * |
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108 * @return The POSIX file attributes |
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109 * |
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110 * @throws UnsupportedOperationException |
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111 * If the {@code PosixFileAttributeView} is not available |
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112 * @throws IOException |
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113 * If an I/O error occurs |
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114 * @throws SecurityException |
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115 * In the case of the default provider, and a security manager is |
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116 * installed, it denies {@link RuntimePermission}<tt>("accessUserInformation")</tt> |
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117 * or its {@link SecurityManager#checkRead(String) checkRead} method |
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118 * denies read access to the file. |
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119 * |
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120 * @see PosixFileAttributeView#readAttributes |
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121 */ |
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122 public static PosixFileAttributes readPosixFileAttributes(FileRef file, |
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123 LinkOption... options) |
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124 throws IOException |
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125 { |
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126 PosixFileAttributeView view = |
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127 file.getFileAttributeView(PosixFileAttributeView.class, options); |
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128 if (view == null) |
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129 throw new UnsupportedOperationException(); |
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130 return view.readAttributes(); |
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131 } |
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132 |
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133 /** |
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134 * Reads the DOS file attributes of a file. |
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135 * |
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136 * <p> The {@code file} parameter locates a file that supports the {@link |
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137 * DosFileAttributeView}. This file attribute view provides access to |
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138 * legacy "DOS" attributes supported by the file systems such as File |
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139 * Allocation Table (FAT), commonly used in <em>consumer devices</em>. It is |
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140 * implementation specific if all file attributes are read as an atomic |
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141 * operation with respect to other file system operations. |
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142 * |
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143 * <p> The {@code options} array may be used to indicate how symbolic links |
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144 * are handled for the case that the file is a symbolic link. By default, |
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145 * symbolic links are followed and the file attributes of the final target |
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146 * of the link are read. If the option {@link LinkOption#NOFOLLOW_LINKS |
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147 * NOFOLLOW_LINKS} is present then symbolic links are not followed and so |
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148 * the method returns the file attributes of the symbolic link itself. |
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149 * |
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150 * @param file |
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151 * A file reference that locates the file |
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152 * @param options |
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153 * Options indicating how symbolic links are handled |
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154 * |
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155 * @return The DOS file attributes |
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156 * |
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157 * @throws UnsupportedOperationException |
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158 * If the {@code DosFileAttributeView} is not available |
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159 * @throws IOException |
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160 * If an I/O error occurs |
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161 * @throws SecurityException |
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162 * In the case of the default provider, the security manager's {@link |
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163 * SecurityManager#checkRead(String) checkRead} method is invoked |
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164 * to check read access to file |
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165 * |
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166 * @see DosFileAttributeView#readAttributes |
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167 */ |
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168 public static DosFileAttributes readDosFileAttributes(FileRef file, |
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169 LinkOption... options) |
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170 throws IOException |
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171 { |
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172 DosFileAttributeView view = |
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173 file.getFileAttributeView(DosFileAttributeView.class, options); |
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174 if (view == null) |
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175 throw new UnsupportedOperationException(); |
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176 return view.readAttributes(); |
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177 } |
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178 |
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179 /** |
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180 * Returns the owner of a file. |
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181 * |
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182 * <p> The {@code file} parameter locates a file that supports the {@link |
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183 * FileOwnerAttributeView}. This file attribute view provides access to |
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184 * a file attribute that is the owner of the file. |
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185 * |
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186 * @param file |
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187 * A file reference that locates the file |
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188 * |
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189 * @return A user principal representing the owner of the file |
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190 * |
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191 * @throws UnsupportedOperationException |
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192 * If the {@code FileOwnerAttributeView} is not available |
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193 * @throws IOException |
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194 * If an I/O error occurs |
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195 * @throws SecurityException |
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196 * In the case of the default provider, and a security manager is |
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197 * installed, it denies {@link RuntimePermission}<tt>("accessUserInformation")</tt> |
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198 * or its {@link SecurityManager#checkRead(String) checkRead} method |
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199 * denies read access to the file. |
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200 * |
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201 * @see FileOwnerAttributeView#getOwner |
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202 */ |
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203 public static UserPrincipal getOwner(FileRef file) throws IOException { |
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204 FileOwnerAttributeView view = |
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205 file.getFileAttributeView(FileOwnerAttributeView.class); |
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206 if (view == null) |
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207 throw new UnsupportedOperationException(); |
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208 return view.getOwner(); |
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209 } |
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210 |
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211 /** |
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212 * Updates the file owner. |
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213 * |
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214 * <p> The {@code file} parameter locates a file that supports the {@link |
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215 * FileOwnerAttributeView}. This file attribute view provides access to |
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216 * a file attribute that is the owner of the file. |
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217 * |
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218 * @param file |
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219 * A file reference that locates the file |
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220 * @param owner |
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221 * The new file owner |
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222 * |
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223 * @throws UnsupportedOperationException |
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224 * If the {@code FileOwnerAttributeView} is not available |
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225 * @throws IOException |
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226 * If an I/O error occurs |
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227 * @throws SecurityException |
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228 * In the case of the default provider, and a security manager is |
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229 * installed, it denies {@link RuntimePermission}<tt>("accessUserInformation")</tt> |
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230 * or its {@link SecurityManager#checkWrite(String) checkWrite} |
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231 * method denies write access to the file. |
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232 * |
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233 * @see FileOwnerAttributeView#setOwner |
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234 */ |
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235 public static void setOwner(FileRef file, UserPrincipal owner) |
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236 throws IOException |
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237 { |
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238 FileOwnerAttributeView view = |
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239 file.getFileAttributeView(FileOwnerAttributeView.class); |
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240 if (view == null) |
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241 throw new UnsupportedOperationException(); |
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242 view.setOwner(owner); |
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243 } |
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244 |
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245 /** |
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246 * Reads a file's Access Control List (ACL). |
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247 * |
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248 * <p> The {@code file} parameter locates a file that supports the {@link |
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249 * AclFileAttributeView}. This file attribute view provides access to ACLs |
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250 * based on the ACL model specified in |
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251 * <a href="http://www.ietf.org/rfc/rfc3530.txt"><i>RFC 3530</i></a>. |
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252 * |
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253 * @param file |
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254 * A file reference that locates the file |
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255 * |
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256 * @return An ordered list of {@link AclEntry entries} representing the |
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257 * ACL. The returned list is modifiable. |
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258 * |
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259 * @throws UnsupportedOperationException |
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260 * If the {@code AclAttributeView} is not available |
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261 * @throws IOException |
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262 * If an I/O error occurs |
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263 * @throws SecurityException |
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264 * In the case of the default provider, and a security manager is |
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265 * installed, it denies {@link RuntimePermission}<tt>("accessUserInformation")</tt> |
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266 * or its {@link SecurityManager#checkRead(String) checkRead} method |
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267 * denies read access to the file. |
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268 * |
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269 * @see AclFileAttributeView#getAcl |
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270 */ |
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271 public static List<AclEntry> getAcl(FileRef file) throws IOException { |
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272 AclFileAttributeView view = |
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273 file.getFileAttributeView(AclFileAttributeView.class); |
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274 if (view == null) |
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275 throw new UnsupportedOperationException(); |
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276 return view.getAcl(); |
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277 } |
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278 |
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279 /** |
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280 * Updates a file's Access Control List (ACL). |
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281 * |
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282 * <p> The {@code file} parameter locates a file that supports the {@link |
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283 * AclFileAttributeView}. This file attribute view provides access to ACLs |
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284 * based on the ACL model specified in |
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285 * <a href="http://www.ietf.org/rfc/rfc3530.txt"><i>RFC 3530</i></a>. |
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286 * |
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287 * @param file |
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288 * A file reference that locates the file |
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289 * @param acl |
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290 * The new file ACL |
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291 * |
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292 * @throws UnsupportedOperationException |
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293 * If the {@code AclFileAttributeView} is not available |
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294 * @throws IOException |
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295 * If an I/O error occurs |
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296 * @throws SecurityException |
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297 * In the case of the default provider, and a security manager is |
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298 * installed, it denies {@link RuntimePermission}<tt>("accessUserInformation")</tt> |
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299 * or its {@link SecurityManager#checkWrite(String) checkWrite} |
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300 * method denies write access to the file. |
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301 * |
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302 * @see AclFileAttributeView#setAcl |
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303 */ |
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304 public static void setAcl(FileRef file, List<AclEntry> acl) |
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305 throws IOException |
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306 { |
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307 AclFileAttributeView view = |
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308 file.getFileAttributeView(AclFileAttributeView.class); |
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309 if (view == null) |
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310 throw new UnsupportedOperationException(); |
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311 view.setAcl(acl); |
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312 } |
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313 |
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314 /** |
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315 * Updates a file's last modified time attribute. The file time is converted |
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316 * to the epoch and precision supported by the file system. Converting from |
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317 * finer to coarser granularities result in precision loss. The behavior of |
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318 * this method when attempting to set a timestamp to a value that is outside |
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319 * the range supported by the underlying file store is not defined. It may |
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320 * or not fail by throwing an {@code IOException}. |
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321 * |
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322 * <p> If the file system does not support a last modified time attribute |
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323 * then this method has no effect. |
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324 * |
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325 * <p> <b>Usage Example:</b> |
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326 * Suppose we want to set the last modified time to the current time: |
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327 * <pre> |
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328 * FileTime now = FileTime.fromMillis(System.currentTimeMillis()); |
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329 * Attributes.setLastModifiedTime(file, now); |
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330 * </pre> |
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331 * |
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332 * @param file |
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333 * A file reference that locates the file |
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334 * @param lastModifiedTime |
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335 * The new last modified time |
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336 * |
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337 * @throws IOException |
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338 * If an I/O error occurs |
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339 * @throws SecurityException |
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340 * In the case of the default provider, the security manager's {@link |
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341 * SecurityManager#checkWrite(String) checkWrite} method is invoked |
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342 * to check write access to file |
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343 * |
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344 * @see BasicFileAttributeView#setTimes |
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345 */ |
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346 public static void setLastModifiedTime(FileRef file, |
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347 FileTime lastModifiedTime) |
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348 throws IOException |
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349 { |
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350 if (lastModifiedTime == null) |
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351 throw new NullPointerException("'lastModifiedTime' is null"); |
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352 file.getFileAttributeView(BasicFileAttributeView.class) |
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353 .setTimes(lastModifiedTime, null, null); |
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354 } |
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355 |
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356 /** |
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357 * Updates a file's last access time attribute. The file time is converted |
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358 * to the epoch and precision supported by the file system. Converting from |
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359 * finer to coarser granularities result in precision loss. The behavior of |
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360 * this method when attempting to set a timestamp to a value that is outside |
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361 * the range supported by the underlying file store is not defined. It may |
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362 * or not fail by throwing an {@code IOException}. |
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363 * |
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364 * <p> If the file system does not support a last access time attribute then |
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365 * this method has no effect. |
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366 * |
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367 * @param file |
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368 * A file reference that locates the file |
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369 * @param lastAccessTime |
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370 * The new last access time |
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371 * |
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372 * @throws IOException |
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373 * If an I/O error occurs |
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374 * @throws SecurityException |
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375 * In the case of the default provider, the security manager's {@link |
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376 * SecurityManager#checkWrite(String) checkWrite} method is invoked |
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377 * to check write access to file |
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378 * |
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379 * @see BasicFileAttributeView#setTimes |
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380 */ |
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381 public static void setLastAccessTime(FileRef file, |
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382 FileTime lastAccessTime) |
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383 throws IOException |
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384 { |
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385 if (lastAccessTime == null) |
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386 throw new NullPointerException("'lastAccessTime' is null"); |
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387 file.getFileAttributeView(BasicFileAttributeView.class) |
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388 .setTimes(null, lastAccessTime, null); |
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389 } |
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390 |
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391 /** |
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392 * Sets a file's POSIX permissions. |
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393 * |
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394 * <p> The {@code file} parameter is a reference to an existing file. It |
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395 * supports the {@link PosixFileAttributeView} that provides access to file |
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396 * attributes commonly associated with files on file systems used by |
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397 * operating systems that implement the Portable Operating System Interface |
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398 * (POSIX) family of standards. |
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399 * |
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400 * @param file |
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401 * A file reference that locates the file |
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402 * @param perms |
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403 * The new set of permissions |
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404 * |
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405 * @throws UnsupportedOperationException |
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406 * If {@code PosixFileAttributeView} is not available |
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407 * @throws ClassCastException |
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408 * If the sets contains elements that are not of type {@code |
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409 * PosixFilePermission} |
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410 * @throws IOException |
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411 * If an I/O error occurs |
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412 * @throws SecurityException |
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413 * In the case of the default provider, and a security manager is |
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414 * installed, it denies {@link RuntimePermission}<tt>("accessUserInformation")</tt> |
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415 * or its {@link SecurityManager#checkWrite(String) checkWrite} |
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416 * method denies write access to the file. |
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417 * |
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418 * @see PosixFileAttributeView#setPermissions |
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419 */ |
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420 public static void setPosixFilePermissions(FileRef file, |
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421 Set<PosixFilePermission> perms) |
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422 throws IOException |
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423 { |
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424 PosixFileAttributeView view = |
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425 file.getFileAttributeView(PosixFileAttributeView.class); |
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426 if (view == null) |
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427 throw new UnsupportedOperationException(); |
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428 view.setPermissions(perms); |
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429 } |
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430 |
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431 /** |
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432 * Reads the space attributes of a file store. |
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433 * |
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434 * <p> The {@code store} parameter is a file store that supports the |
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435 * {@link FileStoreSpaceAttributeView} providing access to the space related |
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436 * attributes of the file store. It is implementation specific if all attributes |
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437 * are read as an atomic operation with respect to other file system operations. |
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438 * |
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439 * @param store |
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440 * The file store |
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441 * |
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442 * @return The file store space attributes |
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443 * |
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444 * @throws UnsupportedOperationException |
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445 * If the file store space attribute view is not supported |
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446 * @throws IOException |
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447 * If an I/O error occurs |
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448 * |
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449 * @see FileStoreSpaceAttributeView#readAttributes() |
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450 */ |
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451 public static FileStoreSpaceAttributes readFileStoreSpaceAttributes(FileStore store) |
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452 throws IOException |
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453 { |
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454 FileStoreSpaceAttributeView view = |
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455 store.getFileStoreAttributeView(FileStoreSpaceAttributeView.class); |
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456 if (view == null) |
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457 throw new UnsupportedOperationException(); |
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458 return view.readAttributes(); |
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459 } |
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460 } |
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