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; 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 endsWith} 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 * <h2>Accessing Files</h2> 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 * BufferedReader reader = Files.newBufferedReader(path, StandardCharsets.UTF_8); 76 * </pre> 77 * 78 * <a name="interop"></a><h2>Interoperability</h2> 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 * <h2>Concurrency</h2> 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 */ getFileSystem()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 */ isAbsolute()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 */ getRoot()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 */ getFileName()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 */ getParent()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 */ getNameCount()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 */ getName(int index)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 */ subpath(int beginIndex, int endIndex)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 */ startsWith(Path other)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 */ startsWith(String other)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 */ endsWith(Path other)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 ends with the given path; otherwise 301 * {@code false} 302 * 303 * @throws InvalidPathException 304 * If the path string cannot be converted to a Path. 305 */ endsWith(String other)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 it is 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 */ normalize()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 */ resolve(Path other)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 */ resolve(String other)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 */ resolveSibling(Path other)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 */ resolveSibling(String other)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 */ relativize(Path other)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 */ toUri()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 java.io.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 */ toAbsolutePath()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 */ toRealPath(LinkOption... options)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 */ toFile()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 register(WatchService watcher, WatchEvent.Kind<?>[] events, WatchEvent.Modifier... modifiers)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 register(WatchService watcher, WatchEvent.Kind<?>... events)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 iterator()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 compareTo(Path other)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 */ equals(Object other)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 */ hashCode()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 */ toString()800 String toString(); 801 } 802