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| 1 | /* | ||
| 2 | * Copyright (c) 2007, 2011, 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; | ||
| 27 | |||
| 28 | import java.io.File; | ||
| 29 | import java.io.IOException; | ||
| 30 | import java.net.URI; | ||
| 31 | import java.util.Iterator; | ||
| 32 | |||
| 33 | /** | ||
| 34 | * An object that may be used to locate a file in a file system. It will | ||
| 35 | * typically represent a system dependent file path. | ||
| 36 | * | ||
| 37 | * <p> A {@code Path} represents a path that is hierarchical and composed of a | ||
| 38 | * sequence of directory and file name elements separated by a special separator | ||
| 39 | * or delimiter. A <em>root component</em>, that identifies a file system | ||
| 40 | * hierarchy, may also be present. The name element that is <em>farthest</em> | ||
| 41 | * from the root of the directory hierarchy is the name of a file or directory. | ||
| 42 | * The other name elements are directory names. A {@code Path} can represent a | ||
| 43 | * root, a root and a sequence of names, or simply one or more name elements. | ||
| 44 | * A {@code Path} is considered to be an <i>empty path</i> if it consists | ||
| 45 | * solely of one name element that is empty. Accessing a file using an | ||
| 46 | * <i>empty path</i> is equivalent to accessing the default directory of the | ||
| 47 | * file system. {@code Path} defines the {@link #getFileName() getFileName}, | ||
| 48 | * {@link #getParent getParent}, {@link #getRoot getRoot}, and {@link #subpath | ||
| 49 | * subpath} methods to access the path components or a subsequence of its name | ||
| 50 | * elements. | ||
| 51 | * | ||
| 52 | * <p> In addition to accessing the components of a path, a {@code Path} also | ||
| 53 | * defines the {@link #resolve(Path) resolve} and {@link #resolveSibling(Path) | ||
| 54 | * resolveSibling} methods to combine paths. The {@link #relativize relativize} | ||
| 55 | * method that can be used to construct a relative path between two paths. | ||
| 56 | * Paths can be {@link #compareTo compared}, and tested against each other using | ||
| 57 | * the {@link #startsWith startsWith} and {@link #endsWith endWith} methods. | ||
| 58 | * | ||
| 59 | * <p> This interface extends {@link Watchable} interface so that a directory | ||
| 60 | * located by a path can be {@link #register registered} with a {@link | ||
| 61 | * WatchService} and entries in the directory watched. </p> | ||
| 62 | * | ||
| 63 | * <p> <b>WARNING:</b> This interface is only intended to be implemented by | ||
| 64 | * those developing custom file system implementations. Methods may be added to | ||
| 65 | * this interface in future releases. </p> | ||
| 66 | * | ||
| 67 | * <a name="interop"><h4>Accessing Files</h4></a> | ||
| 68 | * <p> Paths may be used with the {@link Files} class to operate on files, | ||
| 69 | * directories, and other types of files. For example, suppose we want a {@link | ||
| 70 | * java.io.BufferedReader} to read text from a file "{@code access.log}". The | ||
| 71 | * file is located in a directory "{@code logs}" relative to the current working | ||
| 72 | * directory and is UTF-8 encoded. | ||
| 73 | * <pre> | ||
| 74 | * Path path = FileSystems.getDefault().getPath("logs", "access.log"); | ||
| 75 | * BufferReader reader = Files.newBufferedReader(path, StandardCharsets.UTF_8); | ||
| 76 | * </pre> | ||
| 77 | * | ||
| 78 | * <a name="interop"><h4>Interoperability</h4></a> | ||
| 79 | * <p> Paths associated with the default {@link | ||
| 80 | * java.nio.file.spi.FileSystemProvider provider} are generally interoperable | ||
| 81 | * with the {@link java.io.File java.io.File} class. Paths created by other | ||
| 82 | * providers are unlikely to be interoperable with the abstract path names | ||
| 83 | * represented by {@code java.io.File}. The {@link java.io.File#toPath toPath} | ||
| 84 | * method may be used to obtain a {@code Path} from the abstract path name | ||
| 85 | * represented by a {@code java.io.File} object. The resulting {@code Path} can | ||
| 86 | * be used to operate on the same file as the {@code java.io.File} object. In | ||
| 87 | * addition, the {@link #toFile toFile} method is useful to construct a {@code | ||
| 88 | * File} from the {@code String} representation of a {@code Path}. | ||
| 89 | * | ||
| 90 | * <h4>Concurrency</h4></a> | ||
| 91 | * <p> Implementations of this interface are immutable and safe for use by | ||
| 92 | * multiple concurrent threads. | ||
| 93 | * | ||
| 94 | * @since 1.7 | ||
| 95 | * @see Paths | ||
| 96 | */ | ||
| 97 | |||
| 98 | public interface Path | ||
| 99 | extends Comparable<Path>, Iterable<Path>, Watchable | ||
| 100 | { | ||
| 101 | /** | ||
| 102 | * Returns the file system that created this object. | ||
| 103 | * | ||
| 104 | * @return the file system that created this object | ||
| 105 | */ | ||
| 106 | FileSystem getFileSystem(); | ||
| 107 | |||
| 108 | /** | ||
| 109 | * Tells whether or not this path is absolute. | ||
| 110 | * | ||
| 111 | * <p> An absolute path is complete in that it doesn't need to be combined | ||
| 112 | * with other path information in order to locate a file. | ||
| 113 | * | ||
| 114 | * @return {@code true} if, and only if, this path is absolute | ||
| 115 | */ | ||
| 116 | boolean isAbsolute(); | ||
| 117 | |||
| 118 | /** | ||
| 119 | * Returns the root component of this path as a {@code Path} object, | ||
| 120 | * or {@code null} if this path does not have a root component. | ||
| 121 | * | ||
| 122 | * @return a path representing the root component of this path, | ||
| 123 | * or {@code null} | ||
| 124 | */ | ||
| 125 | Path getRoot(); | ||
| 126 | |||
| 127 | /** | ||
| 128 | * Returns the name of the file or directory denoted by this path as a | ||
| 129 | * {@code Path} object. The file name is the <em>farthest</em> element from | ||
| 130 | * the root in the directory hierarchy. | ||
| 131 | * | ||
| 132 | * @return a path representing the name of the file or directory, or | ||
| 133 | * {@code null} if this path has zero elements | ||
| 134 | */ | ||
| 135 | Path getFileName(); | ||
| 136 | |||
| 137 | /** | ||
| 138 | * Returns the <em>parent path</em>, or {@code null} if this path does not | ||
| 139 | * have a parent. | ||
| 140 | * | ||
| 141 | * <p> The parent of this path object consists of this path's root | ||
| 142 | * component, if any, and each element in the path except for the | ||
| 143 | * <em>farthest</em> from the root in the directory hierarchy. This method | ||
| 144 | * does not access the file system; the path or its parent may not exist. | ||
| 145 | * Furthermore, this method does not eliminate special names such as "." | ||
| 146 | * and ".." that may be used in some implementations. On UNIX for example, | ||
| 147 | * the parent of "{@code /a/b/c}" is "{@code /a/b}", and the parent of | ||
| 148 | * {@code "x/y/.}" is "{@code x/y}". This method may be used with the {@link | ||
| 149 | * #normalize normalize} method, to eliminate redundant names, for cases where | ||
| 150 | * <em>shell-like</em> navigation is required. | ||
| 151 | * | ||
| 152 | * <p> If this path has one or more elements, and no root component, then | ||
| 153 | * this method is equivalent to evaluating the expression: | ||
| 154 | * <blockquote><pre> | ||
| 155 | * subpath(0, getNameCount()-1); | ||
| 156 | * </pre></blockquote> | ||
| 157 | * | ||
| 158 | * @return a path representing the path's parent | ||
| 159 | */ | ||
| 160 | Path getParent(); | ||
| 161 | |||
| 162 | /** | ||
| 163 | * Returns the number of name elements in the path. | ||
| 164 | * | ||
| 165 | * @return the number of elements in the path, or {@code 0} if this path | ||
| 166 | * only represents a root component | ||
| 167 | */ | ||
| 168 | int getNameCount(); | ||
| 169 | |||
| 170 | /** | ||
| 171 | * Returns a name element of this path as a {@code Path} object. | ||
| 172 | * | ||
| 173 | * <p> The {@code index} parameter is the index of the name element to return. | ||
| 174 | * The element that is <em>closest</em> to the root in the directory hierarchy | ||
| 175 | * has index {@code 0}. The element that is <em>farthest</em> from the root | ||
| 176 | * has index {@link #getNameCount count}{@code -1}. | ||
| 177 | * | ||
| 178 | * @param index | ||
| 179 | * the index of the element | ||
| 180 | * | ||
| 181 | * @return the name element | ||
| 182 | * | ||
| 183 | * @throws IllegalArgumentException | ||
| 184 | * if {@code index} is negative, {@code index} is greater than or | ||
| 185 | * equal to the number of elements, or this path has zero name | ||
| 186 | * elements | ||
| 187 | */ | ||
| 188 | Path getName(int index); | ||
| 189 | |||
| 190 | /** | ||
| 191 | * Returns a relative {@code Path} that is a subsequence of the name | ||
| 192 | * elements of this path. | ||
| 193 | * | ||
| 194 | * <p> The {@code beginIndex} and {@code endIndex} parameters specify the | ||
| 195 | * subsequence of name elements. The name that is <em>closest</em> to the root | ||
| 196 | * in the directory hierarchy has index {@code 0}. The name that is | ||
| 197 | * <em>farthest</em> from the root has index {@link #getNameCount | ||
| 198 | * count}{@code -1}. The returned {@code Path} object has the name elements | ||
| 199 | * that begin at {@code beginIndex} and extend to the element at index {@code | ||
| 200 | * endIndex-1}. | ||
| 201 | * | ||
| 202 | * @param beginIndex | ||
| 203 | * the index of the first element, inclusive | ||
| 204 | * @param endIndex | ||
| 205 | * the index of the last element, exclusive | ||
| 206 | * | ||
| 207 | * @return a new {@code Path} object that is a subsequence of the name | ||
| 208 | * elements in this {@code Path} | ||
| 209 | * | ||
| 210 | * @throws IllegalArgumentException | ||
| 211 | * if {@code beginIndex} is negative, or greater than or equal to | ||
| 212 | * the number of elements. If {@code endIndex} is less than or | ||
| 213 | * equal to {@code beginIndex}, or larger than the number of elements. | ||
| 214 | */ | ||
| 215 | Path subpath(int beginIndex, int endIndex); | ||
| 216 | |||
| 217 | /** | ||
| 218 | * Tests if this path starts with the given path. | ||
| 219 | * | ||
| 220 | * <p> This path <em>starts</em> with the given path if this path's root | ||
| 221 | * component <em>starts</em> with the root component of the given path, | ||
| 222 | * and this path starts with the same name elements as the given path. | ||
| 223 | * If the given path has more name elements than this path then {@code false} | ||
| 224 | * is returned. | ||
| 225 | * | ||
| 226 | * <p> Whether or not the root component of this path starts with the root | ||
| 227 | * component of the given path is file system specific. If this path does | ||
| 228 | * not have a root component and the given path has a root component then | ||
| 229 | * this path does not start with the given path. | ||
| 230 | * | ||
| 231 | * <p> If the given path is associated with a different {@code FileSystem} | ||
| 232 | * to this path then {@code false} is returned. | ||
| 233 | * | ||
| 234 | * @param other | ||
| 235 | * the given path | ||
| 236 | * | ||
| 237 | * @return {@code true} if this path starts with the given path; otherwise | ||
| 238 | * {@code false} | ||
| 239 | */ | ||
| 240 | boolean startsWith(Path other); | ||
| 241 | |||
| 242 | /** | ||
| 243 | * Tests if this path starts with a {@code Path}, constructed by converting | ||
| 244 | * the given path string, in exactly the manner specified by the {@link | ||
| 245 | * #startsWith(Path) startsWith(Path)} method. On UNIX for example, the path | ||
| 246 | * "{@code foo/bar}" starts with "{@code foo}" and "{@code foo/bar}". It | ||
| 247 | * does not start with "{@code f}" or "{@code fo}". | ||
| 248 | * | ||
| 249 | * @param other | ||
| 250 | * the given path string | ||
| 251 | * | ||
| 252 | * @return {@code true} if this path starts with the given path; otherwise | ||
| 253 | * {@code false} | ||
| 254 | * | ||
| 255 | * @throws InvalidPathException | ||
| 256 | * If the path string cannot be converted to a Path. | ||
| 257 | */ | ||
| 258 | boolean startsWith(String other); | ||
| 259 | |||
| 260 | /** | ||
| 261 | * Tests if this path ends with the given path. | ||
| 262 | * | ||
| 263 | * <p> If the given path has <em>N</em> elements, and no root component, | ||
| 264 | * and this path has <em>N</em> or more elements, then this path ends with | ||
| 265 | * the given path if the last <em>N</em> elements of each path, starting at | ||
| 266 | * the element farthest from the root, are equal. | ||
| 267 | * | ||
| 268 | * <p> If the given path has a root component then this path ends with the | ||
| 269 | * given path if the root component of this path <em>ends with</em> the root | ||
| 270 | * component of the given path, and the corresponding elements of both paths | ||
| 271 | * are equal. Whether or not the root component of this path ends with the | ||
| 272 | * root component of the given path is file system specific. If this path | ||
| 273 | * does not have a root component and the given path has a root component | ||
| 274 | * then this path does not end with the given path. | ||
| 275 | * | ||
| 276 | * <p> If the given path is associated with a different {@code FileSystem} | ||
| 277 | * to this path then {@code false} is returned. | ||
| 278 | * | ||
| 279 | * @param other | ||
| 280 | * the given path | ||
| 281 | * | ||
| 282 | * @return {@code true} if this path ends with the given path; otherwise | ||
| 283 | * {@code false} | ||
| 284 | */ | ||
| 285 | boolean endsWith(Path other); | ||
| 286 | |||
| 287 | /** | ||
| 288 | * Tests if this path ends with a {@code Path}, constructed by converting | ||
| 289 | * the given path string, in exactly the manner specified by the {@link | ||
| 290 | * #endsWith(Path) endsWith(Path)} method. On UNIX for example, the path | ||
| 291 | * "{@code foo/bar}" ends with "{@code foo/bar}" and "{@code bar}". It does | ||
| 292 | * not end with "{@code r}" or "{@code /bar}". Note that trailing separators | ||
| 293 | * are not taken into account, and so invoking this method on the {@code | ||
| 294 | * Path}"{@code foo/bar}" with the {@code String} "{@code bar/}" returns | ||
| 295 | * {@code true}. | ||
| 296 | * | ||
| 297 | * @param other | ||
| 298 | * the given path string | ||
| 299 | * | ||
| 300 | * @return {@code true} if this path starts with the given path; otherwise | ||
| 301 | * {@code false} | ||
| 302 | * | ||
| 303 | * @throws InvalidPathException | ||
| 304 | * If the path string cannot be converted to a Path. | ||
| 305 | */ | ||
| 306 | boolean endsWith(String other); | ||
| 307 | |||
| 308 | /** | ||
| 309 | * Returns a path that is this path with redundant name elements eliminated. | ||
| 310 | * | ||
| 311 | * <p> The precise definition of this method is implementation dependent but | ||
| 312 | * in general it derives from this path, a path that does not contain | ||
| 313 | * <em>redundant</em> name elements. In many file systems, the "{@code .}" | ||
| 314 | * and "{@code ..}" are special names used to indicate the current directory | ||
| 315 | * and parent directory. In such file systems all occurrences of "{@code .}" | ||
| 316 | * are considered redundant. If a "{@code ..}" is preceded by a | ||
| 317 | * non-"{@code ..}" name then both names are considered redundant (the | ||
| 318 | * process to identify such names is repeated until is it no longer | ||
| 319 | * applicable). | ||
| 320 | * | ||
| 321 | * <p> This method does not access the file system; the path may not locate | ||
| 322 | * a file that exists. Eliminating "{@code ..}" and a preceding name from a | ||
| 323 | * path may result in the path that locates a different file than the original | ||
| 324 | * path. This can arise when the preceding name is a symbolic link. | ||
| 325 | * | ||
| 326 | * @return the resulting path or this path if it does not contain | ||
| 327 | * redundant name elements; an empty path is returned if this path | ||
| 328 | * does have a root component and all name elements are redundant | ||
| 329 | * | ||
| 330 | * @see #getParent | ||
| 331 | * @see #toRealPath | ||
| 332 | */ | ||
| 333 | Path normalize(); | ||
| 334 | |||
| 335 | // -- resolution and relativization -- | ||
| 336 | |||
| 337 | /** | ||
| 338 | * Resolve the given path against this path. | ||
| 339 | * | ||
| 340 | * <p> If the {@code other} parameter is an {@link #isAbsolute() absolute} | ||
| 341 | * path then this method trivially returns {@code other}. If {@code other} | ||
| 342 | * is an <i>empty path</i> then this method trivially returns this path. | ||
| 343 | * Otherwise this method considers this path to be a directory and resolves | ||
| 344 | * the given path against this path. In the simplest case, the given path | ||
| 345 | * does not have a {@link #getRoot root} component, in which case this method | ||
| 346 | * <em>joins</em> the given path to this path and returns a resulting path | ||
| 347 | * that {@link #endsWith ends} with the given path. Where the given path has | ||
| 348 | * a root component then resolution is highly implementation dependent and | ||
| 349 | * therefore unspecified. | ||
| 350 | * | ||
| 351 | * @param other | ||
| 352 | * the path to resolve against this path | ||
| 353 | * | ||
| 354 | * @return the resulting path | ||
| 355 | * | ||
| 356 | * @see #relativize | ||
| 357 | */ | ||
| 358 | Path resolve(Path other); | ||
| 359 | |||
| 360 | /** | ||
| 361 | * Converts a given path string to a {@code Path} and resolves it against | ||
| 362 | * this {@code Path} in exactly the manner specified by the {@link | ||
| 363 | * #resolve(Path) resolve} method. For example, suppose that the name | ||
| 364 | * separator is "{@code /}" and a path represents "{@code foo/bar}", then | ||
| 365 | * invoking this method with the path string "{@code gus}" will result in | ||
| 366 | * the {@code Path} "{@code foo/bar/gus}". | ||
| 367 | * | ||
| 368 | * @param other | ||
| 369 | * the path string to resolve against this path | ||
| 370 | * | ||
| 371 | * @return the resulting path | ||
| 372 | * | ||
| 373 | * @throws InvalidPathException | ||
| 374 | * if the path string cannot be converted to a Path. | ||
| 375 | * | ||
| 376 | * @see FileSystem#getPath | ||
| 377 | */ | ||
| 378 | Path resolve(String other); | ||
| 379 | |||
| 380 | /** | ||
| 381 | * Resolves the given path against this path's {@link #getParent parent} | ||
| 382 | * path. This is useful where a file name needs to be <i>replaced</i> with | ||
| 383 | * another file name. For example, suppose that the name separator is | ||
| 384 | * "{@code /}" and a path represents "{@code dir1/dir2/foo}", then invoking | ||
| 385 | * this method with the {@code Path} "{@code bar}" will result in the {@code | ||
| 386 | * Path} "{@code dir1/dir2/bar}". If this path does not have a parent path, | ||
| 387 | * or {@code other} is {@link #isAbsolute() absolute}, then this method | ||
| 388 | * returns {@code other}. If {@code other} is an empty path then this method | ||
| 389 | * returns this path's parent, or where this path doesn't have a parent, the | ||
| 390 | * empty path. | ||
| 391 | * | ||
| 392 | * @param other | ||
| 393 | * the path to resolve against this path's parent | ||
| 394 | * | ||
| 395 | * @return the resulting path | ||
| 396 | * | ||
| 397 | * @see #resolve(Path) | ||
| 398 | */ | ||
| 399 | Path resolveSibling(Path other); | ||
| 400 | |||
| 401 | /** | ||
| 402 | * Converts a given path string to a {@code Path} and resolves it against | ||
| 403 | * this path's {@link #getParent parent} path in exactly the manner | ||
| 404 | * specified by the {@link #resolveSibling(Path) resolveSibling} method. | ||
| 405 | * | ||
| 406 | * @param other | ||
| 407 | * the path string to resolve against this path's parent | ||
| 408 | * | ||
| 409 | * @return the resulting path | ||
| 410 | * | ||
| 411 | * @throws InvalidPathException | ||
| 412 | * if the path string cannot be converted to a Path. | ||
| 413 | * | ||
| 414 | * @see FileSystem#getPath | ||
| 415 | */ | ||
| 416 | Path resolveSibling(String other); | ||
| 417 | |||
| 418 | /** | ||
| 419 | * Constructs a relative path between this path and a given path. | ||
| 420 | * | ||
| 421 | * <p> Relativization is the inverse of {@link #resolve(Path) resolution}. | ||
| 422 | * This method attempts to construct a {@link #isAbsolute relative} path | ||
| 423 | * that when {@link #resolve(Path) resolved} against this path, yields a | ||
| 424 | * path that locates the same file as the given path. For example, on UNIX, | ||
| 425 | * if this path is {@code "/a/b"} and the given path is {@code "/a/b/c/d"} | ||
| 426 | * then the resulting relative path would be {@code "c/d"}. Where this | ||
| 427 | * path and the given path do not have a {@link #getRoot root} component, | ||
| 428 | * then a relative path can be constructed. A relative path cannot be | ||
| 429 | * constructed if only one of the paths have a root component. Where both | ||
| 430 | * paths have a root component then it is implementation dependent if a | ||
| 431 | * relative path can be constructed. If this path and the given path are | ||
| 432 | * {@link #equals equal} then an <i>empty path</i> is returned. | ||
| 433 | * | ||
| 434 | * <p> For any two {@link #normalize normalized} paths <i>p</i> and | ||
| 435 | * <i>q</i>, where <i>q</i> does not have a root component, | ||
| 436 | * <blockquote> | ||
| 437 | * <i>p</i><tt>.relativize(</tt><i>p</i><tt>.resolve(</tt><i>q</i><tt>)).equals(</tt><i>q</i><tt>)</tt> | ||
| 438 | * </blockquote> | ||
| 439 | * | ||
| 440 | * <p> When symbolic links are supported, then whether the resulting path, | ||
| 441 | * when resolved against this path, yields a path that can be used to locate | ||
| 442 | * the {@link Files#isSameFile same} file as {@code other} is implementation | ||
| 443 | * dependent. For example, if this path is {@code "/a/b"} and the given | ||
| 444 | * path is {@code "/a/x"} then the resulting relative path may be {@code | ||
| 445 | * "../x"}. If {@code "b"} is a symbolic link then is implementation | ||
| 446 | * dependent if {@code "a/b/../x"} would locate the same file as {@code "/a/x"}. | ||
| 447 | * | ||
| 448 | * @param other | ||
| 449 | * the path to relativize against this path | ||
| 450 | * | ||
| 451 | * @return the resulting relative path, or an empty path if both paths are | ||
| 452 | * equal | ||
| 453 | * | ||
| 454 | * @throws IllegalArgumentException | ||
| 455 | * if {@code other} is not a {@code Path} that can be relativized | ||
| 456 | * against this path | ||
| 457 | */ | ||
| 458 | Path relativize(Path other); | ||
| 459 | |||
| 460 | /** | ||
| 461 | * Returns a URI to represent this path. | ||
| 462 | * | ||
| 463 | * <p> This method constructs an absolute {@link URI} with a {@link | ||
| 464 | * URI#getScheme() scheme} equal to the URI scheme that identifies the | ||
| 465 | * provider. The exact form of the scheme specific part is highly provider | ||
| 466 | * dependent. | ||
| 467 | * | ||
| 468 | * <p> In the case of the default provider, the URI is hierarchical with | ||
| 469 | * a {@link URI#getPath() path} component that is absolute. The query and | ||
| 470 | * fragment components are undefined. Whether the authority component is | ||
| 471 | * defined or not is implementation dependent. There is no guarantee that | ||
| 472 | * the {@code URI} may be used to construct a {@link java.io.File java.io.File}. | ||
| 473 | * In particular, if this path represents a Universal Naming Convention (UNC) | ||
| 474 | * path, then the UNC server name may be encoded in the authority component | ||
| 475 | * of the resulting URI. In the case of the default provider, and the file | ||
| 476 | * exists, and it can be determined that the file is a directory, then the | ||
| 477 | * resulting {@code URI} will end with a slash. | ||
| 478 | * | ||
| 479 | * <p> The default provider provides a similar <em>round-trip</em> guarantee | ||
| 480 | * to the {@link java.io.File} class. For a given {@code Path} <i>p</i> it | ||
| 481 | * is guaranteed that | ||
| 482 | * <blockquote><tt> | ||
| 483 | * {@link Paths#get(URI) Paths.get}(</tt><i>p</i><tt>.toUri()).equals(</tt><i>p</i> | ||
| 484 | * <tt>.{@link #toAbsolutePath() toAbsolutePath}())</tt> | ||
| 485 | * </blockquote> | ||
| 486 | * so long as the original {@code Path}, the {@code URI}, and the new {@code | ||
| 487 | * Path} are all created in (possibly different invocations of) the same | ||
| 488 | * Java virtual machine. Whether other providers make any guarantees is | ||
| 489 | * provider specific and therefore unspecified. | ||
| 490 | * | ||
| 491 | * <p> When a file system is constructed to access the contents of a file | ||
| 492 | * as a file system then it is highly implementation specific if the returned | ||
| 493 | * URI represents the given path in the file system or it represents a | ||
| 494 | * <em>compound</em> URI that encodes the URI of the enclosing file system. | ||
| 495 | * A format for compound URIs is not defined in this release; such a scheme | ||
| 496 | * may be added in a future release. | ||
| 497 | * | ||
| 498 | * @return the URI representing this path | ||
| 499 | * | ||
| 500 | * @throws java.io.IOError | ||
| 501 | * if an I/O error occurs obtaining the absolute path, or where a | ||
| 502 | * file system is constructed to access the contents of a file as | ||
| 503 | * a file system, and the URI of the enclosing file system cannot be | ||
| 504 | * obtained | ||
| 505 | * | ||
| 506 | * @throws SecurityException | ||
| 507 | * In the case of the default provider, and a security manager | ||
| 508 | * is installed, the {@link #toAbsolutePath toAbsolutePath} method | ||
| 509 | * throws a security exception. | ||
| 510 | */ | ||
| 511 | URI toUri(); | ||
| 512 | |||
| 513 | /** | ||
| 514 | * Returns a {@code Path} object representing the absolute path of this | ||
| 515 | * path. | ||
| 516 | * | ||
| 517 | * <p> If this path is already {@link Path#isAbsolute absolute} then this | ||
| 518 | * method simply returns this path. Otherwise, this method resolves the path | ||
| 519 | * in an implementation dependent manner, typically by resolving the path | ||
| 520 | * against a file system default directory. Depending on the implementation, | ||
| 521 | * this method may throw an I/O error if the file system is not accessible. | ||
| 522 | * | ||
| 523 | * @return a {@code Path} object representing the absolute path | ||
| 524 | * | ||
| 525 | * @throws IOError | ||
| 526 | * if an I/O error occurs | ||
| 527 | * @throws SecurityException | ||
| 528 | * In the case of the default provider, a security manager | ||
| 529 | * is installed, and this path is not absolute, then the security | ||
| 530 | * manager's {@link SecurityManager#checkPropertyAccess(String) | ||
| 531 | * checkPropertyAccess} method is invoked to check access to the | ||
| 532 | * system property {@code user.dir} | ||
| 533 | */ | ||
| 534 | Path toAbsolutePath(); | ||
| 535 | |||
| 536 | /** | ||
| 537 | * Returns the <em>real</em> path of an existing file. | ||
| 538 | * | ||
| 539 | * <p> The precise definition of this method is implementation dependent but | ||
| 540 | * in general it derives from this path, an {@link #isAbsolute absolute} | ||
| 541 | * path that locates the {@link Files#isSameFile same} file as this path, but | ||
| 542 | * with name elements that represent the actual name of the directories | ||
| 543 | * and the file. For example, where filename comparisons on a file system | ||
| 544 | * are case insensitive then the name elements represent the names in their | ||
| 545 | * actual case. Additionally, the resulting path has redundant name | ||
| 546 | * elements removed. | ||
| 547 | * | ||
| 548 | * <p> If this path is relative then its absolute path is first obtained, | ||
| 549 | * as if by invoking the {@link #toAbsolutePath toAbsolutePath} method. | ||
| 550 | * | ||
| 551 | * <p> The {@code options} array may be used to indicate how symbolic links | ||
| 552 | * are handled. By default, symbolic links are resolved to their final | ||
| 553 | * target. If the option {@link LinkOption#NOFOLLOW_LINKS NOFOLLOW_LINKS} is | ||
| 554 | * present then this method does not resolve symbolic links. | ||
| 555 | * | ||
| 556 | * Some implementations allow special names such as "{@code ..}" to refer to | ||
| 557 | * the parent directory. When deriving the <em>real path</em>, and a | ||
| 558 | * "{@code ..}" (or equivalent) is preceded by a non-"{@code ..}" name then | ||
| 559 | * an implementation will typically cause both names to be removed. When | ||
| 560 | * not resolving symbolic links and the preceding name is a symbolic link | ||
| 561 | * then the names are only removed if it guaranteed that the resulting path | ||
| 562 | * will locate the same file as this path. | ||
| 563 | * | ||
| 564 | * @param options | ||
| 565 | * options indicating how symbolic links are handled | ||
| 566 | * | ||
| 567 | * @return an absolute path represent the <em>real</em> path of the file | ||
| 568 | * located by this object | ||
| 569 | * | ||
| 570 | * @throws IOException | ||
| 571 | * if the file does not exist or an I/O error occurs | ||
| 572 | * @throws SecurityException | ||
| 573 | * In the case of the default provider, and a security manager | ||
| 574 | * is installed, its {@link SecurityManager#checkRead(String) checkRead} | ||
| 575 | * method is invoked to check read access to the file, and where | ||
| 576 | * this path is not absolute, its {@link SecurityManager#checkPropertyAccess(String) | ||
| 577 | * checkPropertyAccess} method is invoked to check access to the | ||
| 578 | * system property {@code user.dir} | ||
| 579 | */ | ||
| 580 | Path toRealPath(LinkOption... options) throws IOException; | ||
| 581 | |||
| 582 | /** | ||
| 583 | * Returns a {@link File} object representing this path. Where this {@code | ||
| 584 | * Path} is associated with the default provider, then this method is | ||
| 585 | * equivalent to returning a {@code File} object constructed with the | ||
| 586 | * {@code String} representation of this path. | ||
| 587 | * | ||
| 588 | * <p> If this path was created by invoking the {@code File} {@link | ||
| 589 | * File#toPath toPath} method then there is no guarantee that the {@code | ||
| 590 | * File} object returned by this method is {@link #equals equal} to the | ||
| 591 | * original {@code File}. | ||
| 592 | * | ||
| 593 | * @return a {@code File} object representing this path | ||
| 594 | * | ||
| 595 | * @throws UnsupportedOperationException | ||
| 596 | * if this {@code Path} is not associated with the default provider | ||
| 597 | */ | ||
| 598 | File toFile(); | ||
| 599 | |||
| 600 | // -- watchable -- | ||
| 601 | |||
| 602 | /** | ||
| 603 | * Registers the file located by this path with a watch service. | ||
| 604 | * | ||
| 605 | * <p> In this release, this path locates a directory that exists. The | ||
| 606 | * directory is registered with the watch service so that entries in the | ||
| 607 | * directory can be watched. The {@code events} parameter is the events to | ||
| 608 | * register and may contain the following events: | ||
| 609 | * <ul> | ||
| 610 | * <li>{@link StandardWatchEventKinds#ENTRY_CREATE ENTRY_CREATE} - | ||
| 611 | * entry created or moved into the directory</li> | ||
| 612 | * <li>{@link StandardWatchEventKinds#ENTRY_DELETE ENTRY_DELETE} - | ||
| 613 | * entry deleted or moved out of the directory</li> | ||
| 614 | * <li>{@link StandardWatchEventKinds#ENTRY_MODIFY ENTRY_MODIFY} - | ||
| 615 | * entry in directory was modified</li> | ||
| 616 | * </ul> | ||
| 617 | * | ||
| 618 | * <p> The {@link WatchEvent#context context} for these events is the | ||
| 619 | * relative path between the directory located by this path, and the path | ||
| 620 | * that locates the directory entry that is created, deleted, or modified. | ||
| 621 | * | ||
| 622 | * <p> The set of events may include additional implementation specific | ||
| 623 | * event that are not defined by the enum {@link StandardWatchEventKinds} | ||
| 624 | * | ||
| 625 | * <p> The {@code modifiers} parameter specifies <em>modifiers</em> that | ||
| 626 | * qualify how the directory is registered. This release does not define any | ||
| 627 | * <em>standard</em> modifiers. It may contain implementation specific | ||
| 628 | * modifiers. | ||
| 629 | * | ||
| 630 | * <p> Where a file is registered with a watch service by means of a symbolic | ||
| 631 | * link then it is implementation specific if the watch continues to depend | ||
| 632 | * on the existence of the symbolic link after it is registered. | ||
| 633 | * | ||
| 634 | * @param watcher | ||
| 635 | * the watch service to which this object is to be registered | ||
| 636 | * @param events | ||
| 637 | * the events for which this object should be registered | ||
| 638 | * @param modifiers | ||
| 639 | * the modifiers, if any, that modify how the object is registered | ||
| 640 | * | ||
| 641 | * @return a key representing the registration of this object with the | ||
| 642 | * given watch service | ||
| 643 | * | ||
| 644 | * @throws UnsupportedOperationException | ||
| 645 | * if unsupported events or modifiers are specified | ||
| 646 | * @throws IllegalArgumentException | ||
| 647 | * if an invalid combination of events or modifiers is specified | ||
| 648 | * @throws ClosedWatchServiceException | ||
| 649 | * if the watch service is closed | ||
| 650 | * @throws NotDirectoryException | ||
| 651 | * if the file is registered to watch the entries in a directory | ||
| 652 | * and the file is not a directory <i>(optional specific exception)</i> | ||
| 653 | * @throws IOException | ||
| 654 | * if an I/O error occurs | ||
| 655 | * @throws SecurityException | ||
| 656 | * In the case of the default provider, and a security manager is | ||
| 657 | * installed, the {@link SecurityManager#checkRead(String) checkRead} | ||
| 658 | * method is invoked to check read access to the file. | ||
| 659 | */ | ||
| 660 | @Override | ||
| 661 | WatchKey register(WatchService watcher, | ||
| 662 | WatchEvent.Kind<?>[] events, | ||
| 663 | WatchEvent.Modifier... modifiers) | ||
| 664 | throws IOException; | ||
| 665 | |||
| 666 | /** | ||
| 667 | * Registers the file located by this path with a watch service. | ||
| 668 | * | ||
| 669 | * <p> An invocation of this method behaves in exactly the same way as the | ||
| 670 | * invocation | ||
| 671 | * <pre> | ||
| 672 | * watchable.{@link #register(WatchService,WatchEvent.Kind[],WatchEvent.Modifier[]) register}(watcher, events, new WatchEvent.Modifier[0]); | ||
| 673 | * </pre> | ||
| 674 | * | ||
| 675 | * <p> <b>Usage Example:</b> | ||
| 676 | * Suppose we wish to register a directory for entry create, delete, and modify | ||
| 677 | * events: | ||
| 678 | * <pre> | ||
| 679 | * Path dir = ... | ||
| 680 | * WatchService watcher = ... | ||
| 681 | * | ||
| 682 | * WatchKey key = dir.register(watcher, ENTRY_CREATE, ENTRY_DELETE, ENTRY_MODIFY); | ||
| 683 | * </pre> | ||
| 684 | * @param watcher | ||
| 685 | * The watch service to which this object is to be registered | ||
| 686 | * @param events | ||
| 687 | * The events for which this object should be registered | ||
| 688 | * | ||
| 689 | * @return A key representing the registration of this object with the | ||
| 690 | * given watch service | ||
| 691 | * | ||
| 692 | * @throws UnsupportedOperationException | ||
| 693 | * If unsupported events are specified | ||
| 694 | * @throws IllegalArgumentException | ||
| 695 | * If an invalid combination of events is specified | ||
| 696 | * @throws ClosedWatchServiceException | ||
| 697 | * If the watch service is closed | ||
| 698 | * @throws NotDirectoryException | ||
| 699 | * If the file is registered to watch the entries in a directory | ||
| 700 | * and the file is not a directory <i>(optional specific exception)</i> | ||
| 701 | * @throws IOException | ||
| 702 | * If an I/O error occurs | ||
| 703 | * @throws SecurityException | ||
| 704 | * In the case of the default provider, and a security manager is | ||
| 705 | * installed, the {@link SecurityManager#checkRead(String) checkRead} | ||
| 706 | * method is invoked to check read access to the file. | ||
| 707 | */ | ||
| 708 | @Override | ||
| 709 | WatchKey register(WatchService watcher, | ||
| 710 | WatchEvent.Kind<?>... events) | ||
| 711 | throws IOException; | ||
| 712 | |||
| 713 | // -- Iterable -- | ||
| 714 | |||
| 715 | /** | ||
| 716 | * Returns an iterator over the name elements of this path. | ||
| 717 | * | ||
| 718 | * <p> The first element returned by the iterator represents the name | ||
| 719 | * element that is closest to the root in the directory hierarchy, the | ||
| 720 | * second element is the next closest, and so on. The last element returned | ||
| 721 | * is the name of the file or directory denoted by this path. The {@link | ||
| 722 | * #getRoot root} component, if present, is not returned by the iterator. | ||
| 723 | * | ||
| 724 | * @return an iterator over the name elements of this path. | ||
| 725 | */ | ||
| 726 | @Override | ||
| 727 | Iterator<Path> iterator(); | ||
| 728 | |||
| 729 | // -- compareTo/equals/hashCode -- | ||
| 730 | |||
| 731 | /** | ||
| 732 | * Compares two abstract paths lexicographically. The ordering defined by | ||
| 733 | * this method is provider specific, and in the case of the default | ||
| 734 | * provider, platform specific. This method does not access the file system | ||
| 735 | * and neither file is required to exist. | ||
| 736 | * | ||
| 737 | * <p> This method may not be used to compare paths that are associated | ||
| 738 | * with different file system providers. | ||
| 739 | * | ||
| 740 | * @param other the path compared to this path. | ||
| 741 | * | ||
| 742 | * @return zero if the argument is {@link #equals equal} to this path, a | ||
| 743 | * value less than zero if this path is lexicographically less than | ||
| 744 | * the argument, or a value greater than zero if this path is | ||
| 745 | * lexicographically greater than the argument | ||
| 746 | * | ||
| 747 | * @throws ClassCastException | ||
| 748 | * if the paths are associated with different providers | ||
| 749 | */ | ||
| 750 | @Override | ||
| 751 | int compareTo(Path other); | ||
| 752 | |||
| 753 | /** | ||
| 754 | * Tests this path for equality with the given object. | ||
| 755 | * | ||
| 756 | * <p> If the given object is not a Path, or is a Path associated with a | ||
| 757 | * different {@code FileSystem}, then this method returns {@code false}. | ||
| 758 | * | ||
| 759 | * <p> Whether or not two path are equal depends on the file system | ||
| 760 | * implementation. In some cases the paths are compared without regard | ||
| 761 | * to case, and others are case sensitive. This method does not access the | ||
| 762 | * file system and the file is not required to exist. Where required, the | ||
| 763 | * {@link Files#isSameFile isSameFile} method may be used to check if two | ||
| 764 | * paths locate the same file. | ||
| 765 | * | ||
| 766 | * <p> This method satisfies the general contract of the {@link | ||
| 767 | * java.lang.Object#equals(Object) Object.equals} method. </p> | ||
| 768 | * | ||
| 769 | * @param other | ||
| 770 | * the object to which this object is to be compared | ||
| 771 | * | ||
| 772 | * @return {@code true} if, and only if, the given object is a {@code Path} | ||
| 773 | * that is identical to this {@code Path} | ||
| 774 | */ | ||
| 775 | boolean equals(Object other); | ||
| 776 | |||
| 777 | /** | ||
| 778 | * Computes a hash code for this path. | ||
| 779 | * | ||
| 780 | * <p> The hash code is based upon the components of the path, and | ||
| 781 | * satisfies the general contract of the {@link Object#hashCode | ||
| 782 | * Object.hashCode} method. | ||
| 783 | * | ||
| 784 | * @return the hash-code value for this path | ||
| 785 | */ | ||
| 786 | int hashCode(); | ||
| 787 | |||
| 788 | /** | ||
| 789 | * Returns the string representation of this path. | ||
| 790 | * | ||
| 791 | * <p> If this path was created by converting a path string using the | ||
| 792 | * {@link FileSystem#getPath getPath} method then the path string returned | ||
| 793 | * by this method may differ from the original String used to create the path. | ||
| 794 | * | ||
| 795 | * <p> The returned path string uses the default name {@link | ||
| 796 | * FileSystem#getSeparator separator} to separate names in the path. | ||
| 797 | * | ||
| 798 | * @return the string representation of this path | ||
| 799 | */ | ||
| 800 | String toString(); | ||
| 801 | } | ||