1 /*
2 * Copyright (c) 1994, 2009, 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.io;
27
28 import java.beans.ConstructorProperties;
29 import java.net.URI;
30 import java.net.URL;
31 import java.net.MalformedURLException;
32 import java.net.URISyntaxException;
33 import java.util.List;
34 import java.util.ArrayList;
35 import java.security.AccessController;
36 import java.security.SecureRandom;
37 import java.nio.file.Path;
38 import java.nio.file.FileSystems;
39 import sun.security.action.GetPropertyAction;
40
41 /**
42 * An abstract representation of file and directory pathnames.
43 *
44 * <p> User interfaces and operating systems use system-dependent <em>pathname
45 * strings</em> to name files and directories. This class presents an
46 * abstract, system-independent view of hierarchical pathnames. An
47 * <em>abstract pathname</em> has two components:
48 *
49 * <ol>
50 * <li> An optional system-dependent <em>prefix</em> string,
51 * such as a disk-drive specifier, <code>"/"</code> for the UNIX root
52 * directory, or <code>"\\\\"</code> for a Microsoft Windows UNC pathname, and
53 * <li> A sequence of zero or more string <em>names</em>.
54 * </ol>
55 *
56 * The first name in an abstract pathname may be a directory name or, in the
57 * case of Microsoft Windows UNC pathnames, a hostname. Each subsequent name
58 * in an abstract pathname denotes a directory; the last name may denote
59 * either a directory or a file. The <em>empty</em> abstract pathname has no
60 * prefix and an empty name sequence.
61 *
62 * <p> The conversion of a pathname string to or from an abstract pathname is
63 * inherently system-dependent. When an abstract pathname is converted into a
64 * pathname string, each name is separated from the next by a single copy of
65 * the default <em>separator character</em>. The default name-separator
66 * character is defined by the system property <code>file.separator</code>, and
67 * is made available in the public static fields <code>{@link
68 * #separator}</code> and <code>{@link #separatorChar}</code> of this class.
69 * When a pathname string is converted into an abstract pathname, the names
70 * within it may be separated by the default name-separator character or by any
71 * other name-separator character that is supported by the underlying system.
72 *
73 * <p> A pathname, whether abstract or in string form, may be either
74 * <em>absolute</em> or <em>relative</em>. An absolute pathname is complete in
75 * that no other information is required in order to locate the file that it
76 * denotes. A relative pathname, in contrast, must be interpreted in terms of
77 * information taken from some other pathname. By default the classes in the
78 * <code>java.io</code> package always resolve relative pathnames against the
79 * current user directory. This directory is named by the system property
80 * <code>user.dir</code>, and is typically the directory in which the Java
81 * virtual machine was invoked.
82 *
83 * <p> The <em>parent</em> of an abstract pathname may be obtained by invoking
84 * the {@link #getParent} method of this class and consists of the pathname's
85 * prefix and each name in the pathname's name sequence except for the last.
86 * Each directory's absolute pathname is an ancestor of any <tt>File</tt>
87 * object with an absolute abstract pathname which begins with the directory's
88 * absolute pathname. For example, the directory denoted by the abstract
89 * pathname <tt>"/usr"</tt> is an ancestor of the directory denoted by the
90 * pathname <tt>"/usr/local/bin"</tt>.
91 *
92 * <p> The prefix concept is used to handle root directories on UNIX platforms,
93 * and drive specifiers, root directories and UNC pathnames on Microsoft Windows platforms,
94 * as follows:
95 *
96 * <ul>
97 *
98 * <li> For UNIX platforms, the prefix of an absolute pathname is always
99 * <code>"/"</code>. Relative pathnames have no prefix. The abstract pathname
100 * denoting the root directory has the prefix <code>"/"</code> and an empty
101 * name sequence.
102 *
103 * <li> For Microsoft Windows platforms, the prefix of a pathname that contains a drive
104 * specifier consists of the drive letter followed by <code>":"</code> and
105 * possibly followed by <code>"\\"</code> if the pathname is absolute. The
106 * prefix of a UNC pathname is <code>"\\\\"</code>; the hostname and the share
107 * name are the first two names in the name sequence. A relative pathname that
108 * does not specify a drive has no prefix.
109 *
110 * </ul>
111 *
112 * <p> Instances of this class may or may not denote an actual file-system
113 * object such as a file or a directory. If it does denote such an object
114 * then that object resides in a <i>partition</i>. A partition is an
115 * operating system-specific portion of storage for a file system. A single
116 * storage device (e.g. a physical disk-drive, flash memory, CD-ROM) may
117 * contain multiple partitions. The object, if any, will reside on the
118 * partition <a name="partName">named</a> by some ancestor of the absolute
119 * form of this pathname.
120 *
121 * <p> A file system may implement restrictions to certain operations on the
122 * actual file-system object, such as reading, writing, and executing. These
123 * restrictions are collectively known as <i>access permissions</i>. The file
124 * system may have multiple sets of access permissions on a single object.
125 * For example, one set may apply to the object's <i>owner</i>, and another
126 * may apply to all other users. The access permissions on an object may
127 * cause some methods in this class to fail.
128 *
129 * <p> Instances of the <code>File</code> class are immutable; that is, once
130 * created, the abstract pathname represented by a <code>File</code> object
131 * will never change.
132 *
133 * <h4>Interoperability with {@code java.nio.file} package</h4>
134 *
135 * <p> The <a href="../../java/nio/file/package-summary.html">{@code java.nio.file}</a>
136 * package defines interfaces and classes for the Java virtual machine to access
137 * files, file attributes, and file systems. This API may be used to overcome
138 * many of the limitations of the {@code java.io.File} class.
139 * The {@link #toPath toPath} method may be used to obtain a {@link
140 * Path} that uses the abstract path represented by a {@code File} object to
141 * locate a file. The resulting {@code Path} may be used with the {@link
142 * java.nio.file.Files} class to provide more efficient and extensive access to
143 * additional file operations, file attributes, and I/O exceptions to help
144 * diagnose errors when an operation on a file fails.
145 *
146 * @author unascribed
147 * @since JDK1.0
148 */
149
150 public class File
151 implements Serializable, Comparable<File>
152 {
153
154 /**
155 * The FileSystem object representing the platform's local file system.
156 */
157 static private FileSystem fs = FileSystem.getFileSystem();
158
159 /**
160 * This abstract pathname's normalized pathname string. A normalized
161 * pathname string uses the default name-separator character and does not
162 * contain any duplicate or redundant separators.
163 *
164 * @serial
165 */
166 private String path;
167
168 /**
169 * The length of this abstract pathname's prefix, or zero if it has no
170 * prefix.
171 */
172 private transient int prefixLength;
173
174 /**
175 * Returns the length of this abstract pathname's prefix.
176 * For use by FileSystem classes.
177 */
178 int getPrefixLength() {
179 return prefixLength;
180 }
181
182 /**
183 * The system-dependent default name-separator character. This field is
184 * initialized to contain the first character of the value of the system
185 * property <code>file.separator</code>. On UNIX systems the value of this
186 * field is <code>'/'</code>; on Microsoft Windows systems it is <code>'\\'</code>.
187 *
188 * @see java.lang.System#getProperty(java.lang.String)
189 */
190 public static final char separatorChar = fs.getSeparator();
191
192 /**
193 * The system-dependent default name-separator character, represented as a
194 * string for convenience. This string contains a single character, namely
195 * <code>{@link #separatorChar}</code>.
196 */
197 public static final String separator = "" + separatorChar;
198
199 /**
200 * The system-dependent path-separator character. This field is
201 * initialized to contain the first character of the value of the system
202 * property <code>path.separator</code>. This character is used to
203 * separate filenames in a sequence of files given as a <em>path list</em>.
204 * On UNIX systems, this character is <code>':'</code>; on Microsoft Windows systems it
205 * is <code>';'</code>.
206 *
207 * @see java.lang.System#getProperty(java.lang.String)
208 */
209 public static final char pathSeparatorChar = fs.getPathSeparator();
210
211 /**
212 * The system-dependent path-separator character, represented as a string
213 * for convenience. This string contains a single character, namely
214 * <code>{@link #pathSeparatorChar}</code>.
215 */
216 public static final String pathSeparator = "" + pathSeparatorChar;
217
218
219 /* -- Constructors -- */
220
221 /**
222 * Internal constructor for already-normalized pathname strings.
223 */
224 private File(String pathname, int prefixLength) {
225 this.path = pathname;
226 this.prefixLength = prefixLength;
227 }
228
229 /**
230 * Internal constructor for already-normalized pathname strings.
231 * The parameter order is used to disambiguate this method from the
232 * public(File, String) constructor.
233 */
234 private File(String child, File parent) {
235 assert parent.path != null;
236 assert (!parent.path.equals(""));
237 this.path = fs.resolve(parent.path, child);
238 this.prefixLength = parent.prefixLength;
239 }
240
241 /**
242 * Creates a new <code>File</code> instance by converting the given
243 * pathname string into an abstract pathname. If the given string is
244 * the empty string, then the result is the empty abstract pathname.
245 *
246 * @param pathname A pathname string
247 * @throws NullPointerException
248 * If the <code>pathname</code> argument is <code>null</code>
249 */
250 @ConstructorProperties("path")
251 public File(String pathname) {
252 if (pathname == null) {
253 throw new NullPointerException();
254 }
255 this.path = fs.normalize(pathname);
256 this.prefixLength = fs.prefixLength(this.path);
257 }
258
259 /* Note: The two-argument File constructors do not interpret an empty
260 parent abstract pathname as the current user directory. An empty parent
261 instead causes the child to be resolved against the system-dependent
262 directory defined by the FileSystem.getDefaultParent method. On Unix
263 this default is "/", while on Microsoft Windows it is "\\". This is required for
264 compatibility with the original behavior of this class. */
265
266 /**
267 * Creates a new <code>File</code> instance from a parent pathname string
268 * and a child pathname string.
269 *
270 * <p> If <code>parent</code> is <code>null</code> then the new
271 * <code>File</code> instance is created as if by invoking the
272 * single-argument <code>File</code> constructor on the given
273 * <code>child</code> pathname string.
274 *
275 * <p> Otherwise the <code>parent</code> pathname string is taken to denote
276 * a directory, and the <code>child</code> pathname string is taken to
277 * denote either a directory or a file. If the <code>child</code> pathname
278 * string is absolute then it is converted into a relative pathname in a
279 * system-dependent way. If <code>parent</code> is the empty string then
280 * the new <code>File</code> instance is created by converting
281 * <code>child</code> into an abstract pathname and resolving the result
282 * against a system-dependent default directory. Otherwise each pathname
283 * string is converted into an abstract pathname and the child abstract
284 * pathname is resolved against the parent.
285 *
286 * @param parent The parent pathname string
287 * @param child The child pathname string
288 * @throws NullPointerException
289 * If <code>child</code> is <code>null</code>
290 */
291 public File(String parent, String child) {
292 if (child == null) {
293 throw new NullPointerException();
294 }
295 if (parent != null) {
296 if (parent.equals("")) {
297 this.path = fs.resolve(fs.getDefaultParent(),
298 fs.normalize(child));
299 } else {
300 this.path = fs.resolve(fs.normalize(parent),
301 fs.normalize(child));
302 }
303 } else {
304 this.path = fs.normalize(child);
305 }
306 this.prefixLength = fs.prefixLength(this.path);
307 }
308
309 /**
310 * Creates a new <code>File</code> instance from a parent abstract
311 * pathname and a child pathname string.
312 *
313 * <p> If <code>parent</code> is <code>null</code> then the new
314 * <code>File</code> instance is created as if by invoking the
315 * single-argument <code>File</code> constructor on the given
316 * <code>child</code> pathname string.
317 *
318 * <p> Otherwise the <code>parent</code> abstract pathname is taken to
319 * denote a directory, and the <code>child</code> pathname string is taken
320 * to denote either a directory or a file. If the <code>child</code>
321 * pathname string is absolute then it is converted into a relative
322 * pathname in a system-dependent way. If <code>parent</code> is the empty
323 * abstract pathname then the new <code>File</code> instance is created by
324 * converting <code>child</code> into an abstract pathname and resolving
325 * the result against a system-dependent default directory. Otherwise each
326 * pathname string is converted into an abstract pathname and the child
327 * abstract pathname is resolved against the parent.
328 *
329 * @param parent The parent abstract pathname
330 * @param child The child pathname string
331 * @throws NullPointerException
332 * If <code>child</code> is <code>null</code>
333 */
334 public File(File parent, String child) {
335 if (child == null) {
336 throw new NullPointerException();
337 }
338 if (parent != null) {
339 if (parent.path.equals("")) {
340 this.path = fs.resolve(fs.getDefaultParent(),
341 fs.normalize(child));
342 } else {
343 this.path = fs.resolve(parent.path,
344 fs.normalize(child));
345 }
346 } else {
347 this.path = fs.normalize(child);
348 }
349 this.prefixLength = fs.prefixLength(this.path);
350 }
351
352 /**
353 * Creates a new <tt>File</tt> instance by converting the given
354 * <tt>file:</tt> URI into an abstract pathname.
355 *
356 * <p> The exact form of a <tt>file:</tt> URI is system-dependent, hence
357 * the transformation performed by this constructor is also
358 * system-dependent.
359 *
360 * <p> For a given abstract pathname <i>f</i> it is guaranteed that
361 *
362 * <blockquote><tt>
363 * new File(</tt><i> f</i><tt>.{@link #toURI() toURI}()).equals(</tt><i> f</i><tt>.{@link #getAbsoluteFile() getAbsoluteFile}())
364 * </tt></blockquote>
365 *
366 * so long as the original abstract pathname, the URI, and the new abstract
367 * pathname are all created in (possibly different invocations of) the same
368 * Java virtual machine. This relationship typically does not hold,
369 * however, when a <tt>file:</tt> URI that is created in a virtual machine
370 * on one operating system is converted into an abstract pathname in a
371 * virtual machine on a different operating system.
372 *
373 * @param uri
374 * An absolute, hierarchical URI with a scheme equal to
375 * <tt>"file"</tt>, a non-empty path component, and undefined
376 * authority, query, and fragment components
377 *
378 * @throws NullPointerException
379 * If <tt>uri</tt> is <tt>null</tt>
380 *
381 * @throws IllegalArgumentException
382 * If the preconditions on the parameter do not hold
383 *
384 * @see #toURI()
385 * @see java.net.URI
386 * @since 1.4
387 */
388 public File(URI uri) {
389
390 // Check our many preconditions
391 if (!uri.isAbsolute())
392 throw new IllegalArgumentException("URI is not absolute");
393 if (uri.isOpaque())
394 throw new IllegalArgumentException("URI is not hierarchical");
395 String scheme = uri.getScheme();
396 if ((scheme == null) || !scheme.equalsIgnoreCase("file"))
397 throw new IllegalArgumentException("URI scheme is not \"file\"");
398 if (uri.getAuthority() != null)
399 throw new IllegalArgumentException("URI has an authority component");
400 if (uri.getFragment() != null)
401 throw new IllegalArgumentException("URI has a fragment component");
402 if (uri.getQuery() != null)
403 throw new IllegalArgumentException("URI has a query component");
404 String p = uri.getPath();
405 if (p.equals(""))
406 throw new IllegalArgumentException("URI path component is empty");
407
408 // Okay, now initialize
409 p = fs.fromURIPath(p);
410 if (File.separatorChar != '/')
411 p = p.replace('/', File.separatorChar);
412 this.path = fs.normalize(p);
413 this.prefixLength = fs.prefixLength(this.path);
414 }
415
416
417 /* -- Path-component accessors -- */
418
419 /**
420 * Returns the name of the file or directory denoted by this abstract
421 * pathname. This is just the last name in the pathname's name
422 * sequence. If the pathname's name sequence is empty, then the empty
423 * string is returned.
424 *
425 * @return The name of the file or directory denoted by this abstract
426 * pathname, or the empty string if this pathname's name sequence
427 * is empty
428 */
429 public String getName() {
430 int index = path.lastIndexOf(separatorChar);
431 if (index < prefixLength) return path.substring(prefixLength);
432 return path.substring(index + 1);
433 }
434
435 /**
436 * Returns the pathname string of this abstract pathname's parent, or
437 * <code>null</code> if this pathname does not name a parent directory.
438 *
439 * <p> The <em>parent</em> of an abstract pathname consists of the
440 * pathname's prefix, if any, and each name in the pathname's name
441 * sequence except for the last. If the name sequence is empty then
442 * the pathname does not name a parent directory.
443 *
444 * @return The pathname string of the parent directory named by this
445 * abstract pathname, or <code>null</code> if this pathname
446 * does not name a parent
447 */
448 public String getParent() {
449 int index = path.lastIndexOf(separatorChar);
450 if (index < prefixLength) {
451 if ((prefixLength > 0) && (path.length() > prefixLength))
452 return path.substring(0, prefixLength);
453 return null;
454 }
455 return path.substring(0, index);
456 }
457
458 /**
459 * Returns the abstract pathname of this abstract pathname's parent,
460 * or <code>null</code> if this pathname does not name a parent
461 * directory.
462 *
463 * <p> The <em>parent</em> of an abstract pathname consists of the
464 * pathname's prefix, if any, and each name in the pathname's name
465 * sequence except for the last. If the name sequence is empty then
466 * the pathname does not name a parent directory.
467 *
468 * @return The abstract pathname of the parent directory named by this
469 * abstract pathname, or <code>null</code> if this pathname
470 * does not name a parent
471 *
472 * @since 1.2
473 */
474 public File getParentFile() {
475 String p = this.getParent();
476 if (p == null) return null;
477 return new File(p, this.prefixLength);
478 }
479
480 /**
481 * Converts this abstract pathname into a pathname string. The resulting
482 * string uses the {@link #separator default name-separator character} to
483 * separate the names in the name sequence.
484 *
485 * @return The string form of this abstract pathname
486 */
487 public String getPath() {
488 return path;
489 }
490
491
492 /* -- Path operations -- */
493
494 /**
495 * Tests whether this abstract pathname is absolute. The definition of
496 * absolute pathname is system dependent. On UNIX systems, a pathname is
497 * absolute if its prefix is <code>"/"</code>. On Microsoft Windows systems, a
498 * pathname is absolute if its prefix is a drive specifier followed by
499 * <code>"\\"</code>, or if its prefix is <code>"\\\\"</code>.
500 *
501 * @return <code>true</code> if this abstract pathname is absolute,
502 * <code>false</code> otherwise
503 */
504 public boolean isAbsolute() {
505 return fs.isAbsolute(this);
506 }
507
508 /**
509 * Returns the absolute pathname string of this abstract pathname.
510 *
511 * <p> If this abstract pathname is already absolute, then the pathname
512 * string is simply returned as if by the <code>{@link #getPath}</code>
513 * method. If this abstract pathname is the empty abstract pathname then
514 * the pathname string of the current user directory, which is named by the
515 * system property <code>user.dir</code>, is returned. Otherwise this
516 * pathname is resolved in a system-dependent way. On UNIX systems, a
517 * relative pathname is made absolute by resolving it against the current
518 * user directory. On Microsoft Windows systems, a relative pathname is made absolute
519 * by resolving it against the current directory of the drive named by the
520 * pathname, if any; if not, it is resolved against the current user
521 * directory.
522 *
523 * @return The absolute pathname string denoting the same file or
524 * directory as this abstract pathname
525 *
526 * @throws SecurityException
527 * If a required system property value cannot be accessed.
528 *
529 * @see java.io.File#isAbsolute()
530 */
531 public String getAbsolutePath() {
532 return fs.resolve(this);
533 }
534
535 /**
536 * Returns the absolute form of this abstract pathname. Equivalent to
537 * <code>new File(this.{@link #getAbsolutePath})</code>.
538 *
539 * @return The absolute abstract pathname denoting the same file or
540 * directory as this abstract pathname
541 *
542 * @throws SecurityException
543 * If a required system property value cannot be accessed.
544 *
545 * @since 1.2
546 */
547 public File getAbsoluteFile() {
548 String absPath = getAbsolutePath();
549 return new File(absPath, fs.prefixLength(absPath));
550 }
551
552 /**
553 * Returns the canonical pathname string of this abstract pathname.
554 *
555 * <p> A canonical pathname is both absolute and unique. The precise
556 * definition of canonical form is system-dependent. This method first
557 * converts this pathname to absolute form if necessary, as if by invoking the
558 * {@link #getAbsolutePath} method, and then maps it to its unique form in a
559 * system-dependent way. This typically involves removing redundant names
560 * such as <tt>"."</tt> and <tt>".."</tt> from the pathname, resolving
561 * symbolic links (on UNIX platforms), and converting drive letters to a
562 * standard case (on Microsoft Windows platforms).
563 *
564 * <p> Every pathname that denotes an existing file or directory has a
565 * unique canonical form. Every pathname that denotes a nonexistent file
566 * or directory also has a unique canonical form. The canonical form of
567 * the pathname of a nonexistent file or directory may be different from
568 * the canonical form of the same pathname after the file or directory is
569 * created. Similarly, the canonical form of the pathname of an existing
570 * file or directory may be different from the canonical form of the same
571 * pathname after the file or directory is deleted.
572 *
573 * @return The canonical pathname string denoting the same file or
574 * directory as this abstract pathname
575 *
576 * @throws IOException
577 * If an I/O error occurs, which is possible because the
578 * construction of the canonical pathname may require
579 * filesystem queries
580 *
581 * @throws SecurityException
582 * If a required system property value cannot be accessed, or
583 * if a security manager exists and its <code>{@link
584 * java.lang.SecurityManager#checkRead}</code> method denies
585 * read access to the file
586 *
587 * @since JDK1.1
588 * @see Path#toRealPath
589 */
590 public String getCanonicalPath() throws IOException {
591 return fs.canonicalize(fs.resolve(this));
592 }
593
594 /**
595 * Returns the canonical form of this abstract pathname. Equivalent to
596 * <code>new File(this.{@link #getCanonicalPath})</code>.
597 *
598 * @return The canonical pathname string denoting the same file or
599 * directory as this abstract pathname
600 *
601 * @throws IOException
602 * If an I/O error occurs, which is possible because the
603 * construction of the canonical pathname may require
604 * filesystem queries
605 *
606 * @throws SecurityException
607 * If a required system property value cannot be accessed, or
608 * if a security manager exists and its <code>{@link
609 * java.lang.SecurityManager#checkRead}</code> method denies
610 * read access to the file
611 *
612 * @since 1.2
613 * @see Path#toRealPath
614 */
615 public File getCanonicalFile() throws IOException {
616 String canonPath = getCanonicalPath();
617 return new File(canonPath, fs.prefixLength(canonPath));
618 }
619
620 private static String slashify(String path, boolean isDirectory) {
621 String p = path;
622 if (File.separatorChar != '/')
623 p = p.replace(File.separatorChar, '/');
624 if (!p.startsWith("/"))
625 p = "/" + p;
626 if (!p.endsWith("/") && isDirectory)
627 p = p + "/";
628 return p;
629 }
630
631 /**
632 * Converts this abstract pathname into a <code>file:</code> URL. The
633 * exact form of the URL is system-dependent. If it can be determined that
634 * the file denoted by this abstract pathname is a directory, then the
635 * resulting URL will end with a slash.
636 *
637 * @return A URL object representing the equivalent file URL
638 *
639 * @throws MalformedURLException
640 * If the path cannot be parsed as a URL
641 *
642 * @see #toURI()
643 * @see java.net.URI
644 * @see java.net.URI#toURL()
645 * @see java.net.URL
646 * @since 1.2
647 *
648 * @deprecated This method does not automatically escape characters that
649 * are illegal in URLs. It is recommended that new code convert an
650 * abstract pathname into a URL by first converting it into a URI, via the
651 * {@link #toURI() toURI} method, and then converting the URI into a URL
652 * via the {@link java.net.URI#toURL() URI.toURL} method.
653 */
654 @Deprecated
655 public URL toURL() throws MalformedURLException {
656 return new URL("file", "", slashify(getAbsolutePath(), isDirectory()));
657 }
658
659 /**
660 * Constructs a <tt>file:</tt> URI that represents this abstract pathname.
661 *
662 * <p> The exact form of the URI is system-dependent. If it can be
663 * determined that the file denoted by this abstract pathname is a
664 * directory, then the resulting URI will end with a slash.
665 *
666 * <p> For a given abstract pathname <i>f</i>, it is guaranteed that
667 *
668 * <blockquote><tt>
669 * new {@link #File(java.net.URI) File}(</tt><i> f</i><tt>.toURI()).equals(</tt><i> f</i><tt>.{@link #getAbsoluteFile() getAbsoluteFile}())
670 * </tt></blockquote>
671 *
672 * so long as the original abstract pathname, the URI, and the new abstract
673 * pathname are all created in (possibly different invocations of) the same
674 * Java virtual machine. Due to the system-dependent nature of abstract
675 * pathnames, however, this relationship typically does not hold when a
676 * <tt>file:</tt> URI that is created in a virtual machine on one operating
677 * system is converted into an abstract pathname in a virtual machine on a
678 * different operating system.
679 *
680 * <p> Note that when this abstract pathname represents a UNC pathname then
681 * all components of the UNC (including the server name component) are encoded
682 * in the {@code URI} path. The authority component is undefined, meaning
683 * that it is represented as {@code null}. The {@link Path} class defines the
684 * {@link Path#toUri toUri} method to encode the server name in the authority
685 * component of the resulting {@code URI}. The {@link #toPath toPath} method
686 * may be used to obtain a {@code Path} representing this abstract pathname.
687 *
688 * @return An absolute, hierarchical URI with a scheme equal to
689 * <tt>"file"</tt>, a path representing this abstract pathname,
690 * and undefined authority, query, and fragment components
691 * @throws SecurityException If a required system property value cannot
692 * be accessed.
693 *
694 * @see #File(java.net.URI)
695 * @see java.net.URI
696 * @see java.net.URI#toURL()
697 * @since 1.4
698 */
699 public URI toURI() {
700 try {
701 File f = getAbsoluteFile();
702 String sp = slashify(f.getPath(), f.isDirectory());
703 if (sp.startsWith("//"))
704 sp = "//" + sp;
705 return new URI("file", null, sp, null);
706 } catch (URISyntaxException x) {
707 throw new Error(x); // Can't happen
708 }
709 }
710
711
712 /* -- Attribute accessors -- */
713
714 /**
715 * Tests whether the application can read the file denoted by this
716 * abstract pathname.
717 *
718 * @return <code>true</code> if and only if the file specified by this
719 * abstract pathname exists <em>and</em> can be read by the
720 * application; <code>false</code> otherwise
721 *
722 * @throws SecurityException
723 * If a security manager exists and its <code>{@link
724 * java.lang.SecurityManager#checkRead(java.lang.String)}</code>
725 * method denies read access to the file
726 */
727 public boolean canRead() {
728 SecurityManager security = System.getSecurityManager();
729 if (security != null) {
730 security.checkRead(path);
731 }
732 return fs.checkAccess(this, FileSystem.ACCESS_READ);
733 }
734
735 /**
736 * Tests whether the application can modify the file denoted by this
737 * abstract pathname.
738 *
739 * @return <code>true</code> if and only if the file system actually
740 * contains a file denoted by this abstract pathname <em>and</em>
741 * the application is allowed to write to the file;
742 * <code>false</code> otherwise.
743 *
744 * @throws SecurityException
745 * If a security manager exists and its <code>{@link
746 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
747 * method denies write access to the file
748 */
749 public boolean canWrite() {
750 SecurityManager security = System.getSecurityManager();
751 if (security != null) {
752 security.checkWrite(path);
753 }
754 return fs.checkAccess(this, FileSystem.ACCESS_WRITE);
755 }
756
757 /**
758 * Tests whether the file or directory denoted by this abstract pathname
759 * exists.
760 *
761 * @return <code>true</code> if and only if the file or directory denoted
762 * by this abstract pathname exists; <code>false</code> otherwise
763 *
764 * @throws SecurityException
765 * If a security manager exists and its <code>{@link
766 * java.lang.SecurityManager#checkRead(java.lang.String)}</code>
767 * method denies read access to the file or directory
768 */
769 public boolean exists() {
770 SecurityManager security = System.getSecurityManager();
771 if (security != null) {
772 security.checkRead(path);
773 }
774 return ((fs.getBooleanAttributes(this) & FileSystem.BA_EXISTS) != 0);
775 }
776
777 /**
778 * Tests whether the file denoted by this abstract pathname is a
779 * directory.
780 *
781 * <p> Where it is required to distinguish an I/O exception from the case
782 * that the file is not a directory, or where several attributes of the
783 * same file are required at the same time, then the {@link
784 * java.nio.file.Files#readAttributes(Path,Class,LinkOption[])
785 * Files.readAttributes} method may be used.
786 *
787 * @return <code>true</code> if and only if the file denoted by this
788 * abstract pathname exists <em>and</em> is a directory;
789 * <code>false</code> otherwise
790 *
791 * @throws SecurityException
792 * If a security manager exists and its <code>{@link
793 * java.lang.SecurityManager#checkRead(java.lang.String)}</code>
794 * method denies read access to the file
795 */
796 public boolean isDirectory() {
797 SecurityManager security = System.getSecurityManager();
798 if (security != null) {
799 security.checkRead(path);
800 }
801 return ((fs.getBooleanAttributes(this) & FileSystem.BA_DIRECTORY)
802 != 0);
803 }
804
805 /**
806 * Tests whether the file denoted by this abstract pathname is a normal
807 * file. A file is <em>normal</em> if it is not a directory and, in
808 * addition, satisfies other system-dependent criteria. Any non-directory
809 * file created by a Java application is guaranteed to be a normal file.
810 *
811 * <p> Where it is required to distinguish an I/O exception from the case
812 * that the file is not a normal file, or where several attributes of the
813 * same file are required at the same time, then the {@link
814 * java.nio.file.Files#readAttributes(Path,Class,LinkOption[])
815 * Files.readAttributes} method may be used.
816 *
817 * @return <code>true</code> if and only if the file denoted by this
818 * abstract pathname exists <em>and</em> is a normal file;
819 * <code>false</code> otherwise
820 *
821 * @throws SecurityException
822 * If a security manager exists and its <code>{@link
823 * java.lang.SecurityManager#checkRead(java.lang.String)}</code>
824 * method denies read access to the file
825 */
826 public boolean isFile() {
827 SecurityManager security = System.getSecurityManager();
828 if (security != null) {
829 security.checkRead(path);
830 }
831 return ((fs.getBooleanAttributes(this) & FileSystem.BA_REGULAR) != 0);
832 }
833
834 /**
835 * Tests whether the file named by this abstract pathname is a hidden
836 * file. The exact definition of <em>hidden</em> is system-dependent. On
837 * UNIX systems, a file is considered to be hidden if its name begins with
838 * a period character (<code>'.'</code>). On Microsoft Windows systems, a file is
839 * considered to be hidden if it has been marked as such in the filesystem.
840 *
841 * @return <code>true</code> if and only if the file denoted by this
842 * abstract pathname is hidden according to the conventions of the
843 * underlying platform
844 *
845 * @throws SecurityException
846 * If a security manager exists and its <code>{@link
847 * java.lang.SecurityManager#checkRead(java.lang.String)}</code>
848 * method denies read access to the file
849 *
850 * @since 1.2
851 */
852 public boolean isHidden() {
853 SecurityManager security = System.getSecurityManager();
854 if (security != null) {
855 security.checkRead(path);
856 }
857 return ((fs.getBooleanAttributes(this) & FileSystem.BA_HIDDEN) != 0);
858 }
859
860 /**
861 * Returns the time that the file denoted by this abstract pathname was
862 * last modified.
863 *
864 * <p> Where it is required to distinguish an I/O exception from the case
865 * where {@code 0L} is returned, or where several attributes of the
866 * same file are required at the same time, or where the time of last
867 * access or the creation time are required, then the {@link
868 * java.nio.file.Files#readAttributes(Path,Class,LinkOption[])
869 * Files.readAttributes} method may be used.
870 *
871 * @return A <code>long</code> value representing the time the file was
872 * last modified, measured in milliseconds since the epoch
873 * (00:00:00 GMT, January 1, 1970), or <code>0L</code> if the
874 * file does not exist or if an I/O error occurs
875 *
876 * @throws SecurityException
877 * If a security manager exists and its <code>{@link
878 * java.lang.SecurityManager#checkRead(java.lang.String)}</code>
879 * method denies read access to the file
880 */
881 public long lastModified() {
882 SecurityManager security = System.getSecurityManager();
883 if (security != null) {
884 security.checkRead(path);
885 }
886 return fs.getLastModifiedTime(this);
887 }
888
889 /**
890 * Returns the length of the file denoted by this abstract pathname.
891 * The return value is unspecified if this pathname denotes a directory.
892 *
893 * <p> Where it is required to distinguish an I/O exception from the case
894 * that {@code 0L} is returned, or where several attributes of the same file
895 * are required at the same time, then the {@link
896 * java.nio.file.Files#readAttributes(Path,Class,LinkOption[])
897 * Files.readAttributes} method may be used.
898 *
899 * @return The length, in bytes, of the file denoted by this abstract
900 * pathname, or <code>0L</code> if the file does not exist. Some
901 * operating systems may return <code>0L</code> for pathnames
902 * denoting system-dependent entities such as devices or pipes.
903 *
904 * @throws SecurityException
905 * If a security manager exists and its <code>{@link
906 * java.lang.SecurityManager#checkRead(java.lang.String)}</code>
907 * method denies read access to the file
908 */
909 public long length() {
910 SecurityManager security = System.getSecurityManager();
911 if (security != null) {
912 security.checkRead(path);
913 }
914 return fs.getLength(this);
915 }
916
917
918 /* -- File operations -- */
919
920 /**
921 * Atomically creates a new, empty file named by this abstract pathname if
922 * and only if a file with this name does not yet exist. The check for the
923 * existence of the file and the creation of the file if it does not exist
924 * are a single operation that is atomic with respect to all other
925 * filesystem activities that might affect the file.
926 * <P>
927 * Note: this method should <i>not</i> be used for file-locking, as
928 * the resulting protocol cannot be made to work reliably. The
929 * {@link java.nio.channels.FileLock FileLock}
930 * facility should be used instead.
931 *
932 * @return <code>true</code> if the named file does not exist and was
933 * successfully created; <code>false</code> if the named file
934 * already exists
935 *
936 * @throws IOException
937 * If an I/O error occurred
938 *
939 * @throws SecurityException
940 * If a security manager exists and its <code>{@link
941 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
942 * method denies write access to the file
943 *
944 * @since 1.2
945 */
946 public boolean createNewFile() throws IOException {
947 SecurityManager security = System.getSecurityManager();
948 if (security != null) security.checkWrite(path);
949 return fs.createFileExclusively(path);
950 }
951
952 /**
953 * Deletes the file or directory denoted by this abstract pathname. If
954 * this pathname denotes a directory, then the directory must be empty in
955 * order to be deleted.
956 *
957 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
958 * java.nio.file.Files#delete(Path) delete} method to throw an {@link IOException}
959 * when a file cannot be deleted. This is useful for error reporting and to
960 * diagnose why a file cannot be deleted.
961 *
962 * @return <code>true</code> if and only if the file or directory is
963 * successfully deleted; <code>false</code> otherwise
964 *
965 * @throws SecurityException
966 * If a security manager exists and its <code>{@link
967 * java.lang.SecurityManager#checkDelete}</code> method denies
968 * delete access to the file
969 */
970 public boolean delete() {
971 SecurityManager security = System.getSecurityManager();
972 if (security != null) {
973 security.checkDelete(path);
974 }
975 return fs.delete(this);
976 }
977
978 /**
979 * Requests that the file or directory denoted by this abstract
980 * pathname be deleted when the virtual machine terminates.
981 * Files (or directories) are deleted in the reverse order that
982 * they are registered. Invoking this method to delete a file or
983 * directory that is already registered for deletion has no effect.
984 * Deletion will be attempted only for normal termination of the
985 * virtual machine, as defined by the Java Language Specification.
986 *
987 * <p> Once deletion has been requested, it is not possible to cancel the
988 * request. This method should therefore be used with care.
989 *
990 * <P>
991 * Note: this method should <i>not</i> be used for file-locking, as
992 * the resulting protocol cannot be made to work reliably. The
993 * {@link java.nio.channels.FileLock FileLock}
994 * facility should be used instead.
995 *
996 * @throws SecurityException
997 * If a security manager exists and its <code>{@link
998 * java.lang.SecurityManager#checkDelete}</code> method denies
999 * delete access to the file
1000 *
1001 * @see #delete
1002 *
1003 * @since 1.2
1004 */
1005 public void deleteOnExit() {
1006 SecurityManager security = System.getSecurityManager();
1007 if (security != null) {
1008 security.checkDelete(path);
1009 }
1010 DeleteOnExitHook.add(path);
1011 }
1012
1013 /**
1014 * Returns an array of strings naming the files and directories in the
1015 * directory denoted by this abstract pathname.
1016 *
1017 * <p> If this abstract pathname does not denote a directory, then this
1018 * method returns {@code null}. Otherwise an array of strings is
1019 * returned, one for each file or directory in the directory. Names
1020 * denoting the directory itself and the directory's parent directory are
1021 * not included in the result. Each string is a file name rather than a
1022 * complete path.
1023 *
1024 * <p> There is no guarantee that the name strings in the resulting array
1025 * will appear in any specific order; they are not, in particular,
1026 * guaranteed to appear in alphabetical order.
1027 *
1028 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1029 * java.nio.file.Files#newDirectoryStream(Path) newDirectoryStream} method to
1030 * open a directory and iterate over the names of the files in the directory.
1031 * This may use less resources when working with very large directories, and
1032 * may be more responsive when working with remote directories.
1033 *
1034 * @return An array of strings naming the files and directories in the
1035 * directory denoted by this abstract pathname. The array will be
1036 * empty if the directory is empty. Returns {@code null} if
1037 * this abstract pathname does not denote a directory, or if an
1038 * I/O error occurs.
1039 *
1040 * @throws SecurityException
1041 * If a security manager exists and its {@link
1042 * SecurityManager#checkRead(String)} method denies read access to
1043 * the directory
1044 */
1045 public String[] list() {
1046 SecurityManager security = System.getSecurityManager();
1047 if (security != null) {
1048 security.checkRead(path);
1049 }
1050 return fs.list(this);
1051 }
1052
1053 /**
1054 * Returns an array of strings naming the files and directories in the
1055 * directory denoted by this abstract pathname that satisfy the specified
1056 * filter. The behavior of this method is the same as that of the
1057 * {@link #list()} method, except that the strings in the returned array
1058 * must satisfy the filter. If the given {@code filter} is {@code null}
1059 * then all names are accepted. Otherwise, a name satisfies the filter if
1060 * and only if the value {@code true} results when the {@link
1061 * FilenameFilter#accept FilenameFilter.accept(File, String)} method
1062 * of the filter is invoked on this abstract pathname and the name of a
1063 * file or directory in the directory that it denotes.
1064 *
1065 * @param filter
1066 * A filename filter
1067 *
1068 * @return An array of strings naming the files and directories in the
1069 * directory denoted by this abstract pathname that were accepted
1070 * by the given {@code filter}. The array will be empty if the
1071 * directory is empty or if no names were accepted by the filter.
1072 * Returns {@code null} if this abstract pathname does not denote
1073 * a directory, or if an I/O error occurs.
1074 *
1075 * @throws SecurityException
1076 * If a security manager exists and its {@link
1077 * SecurityManager#checkRead(String)} method denies read access to
1078 * the directory
1079 *
1080 * @see java.nio.file.Files#newDirectoryStream(Path,String)
1081 */
1082 public String[] list(FilenameFilter filter) {
1083 String names[] = list();
1084 if ((names == null) || (filter == null)) {
1085 return names;
1086 }
1087 List<String> v = new ArrayList<>();
1088 for (int i = 0 ; i < names.length ; i++) {
1089 if (filter.accept(this, names[i])) {
1090 v.add(names[i]);
1091 }
1092 }
1093 return v.toArray(new String[v.size()]);
1094 }
1095
1096 /**
1097 * Returns an array of abstract pathnames denoting the files in the
1098 * directory denoted by this abstract pathname.
1099 *
1100 * <p> If this abstract pathname does not denote a directory, then this
1101 * method returns {@code null}. Otherwise an array of {@code File} objects
1102 * is returned, one for each file or directory in the directory. Pathnames
1103 * denoting the directory itself and the directory's parent directory are
1104 * not included in the result. Each resulting abstract pathname is
1105 * constructed from this abstract pathname using the {@link #File(File,
1106 * String) File(File, String)} constructor. Therefore if this
1107 * pathname is absolute then each resulting pathname is absolute; if this
1108 * pathname is relative then each resulting pathname will be relative to
1109 * the same directory.
1110 *
1111 * <p> There is no guarantee that the name strings in the resulting array
1112 * will appear in any specific order; they are not, in particular,
1113 * guaranteed to appear in alphabetical order.
1114 *
1115 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1116 * java.nio.file.Files#newDirectoryStream(Path) newDirectoryStream} method
1117 * to open a directory and iterate over the names of the files in the
1118 * directory. This may use less resources when working with very large
1119 * directories.
1120 *
1121 * @return An array of abstract pathnames denoting the files and
1122 * directories in the directory denoted by this abstract pathname.
1123 * The array will be empty if the directory is empty. Returns
1124 * {@code null} if this abstract pathname does not denote a
1125 * directory, or if an I/O error occurs.
1126 *
1127 * @throws SecurityException
1128 * If a security manager exists and its {@link
1129 * SecurityManager#checkRead(String)} method denies read access to
1130 * the directory
1131 *
1132 * @since 1.2
1133 */
1134 public File[] listFiles() {
1135 String[] ss = list();
1136 if (ss == null) return null;
1137 int n = ss.length;
1138 File[] fs = new File[n];
1139 for (int i = 0; i < n; i++) {
1140 fs[i] = new File(ss[i], this);
1141 }
1142 return fs;
1143 }
1144
1145 /**
1146 * Returns an array of abstract pathnames denoting the files and
1147 * directories in the directory denoted by this abstract pathname that
1148 * satisfy the specified filter. The behavior of this method is the same
1149 * as that of the {@link #listFiles()} method, except that the pathnames in
1150 * the returned array must satisfy the filter. If the given {@code filter}
1151 * is {@code null} then all pathnames are accepted. Otherwise, a pathname
1152 * satisfies the filter if and only if the value {@code true} results when
1153 * the {@link FilenameFilter#accept
1154 * FilenameFilter.accept(File, String)} method of the filter is
1155 * invoked on this abstract pathname and the name of a file or directory in
1156 * the directory that it denotes.
1157 *
1158 * @param filter
1159 * A filename filter
1160 *
1161 * @return An array of abstract pathnames denoting the files and
1162 * directories in the directory denoted by this abstract pathname.
1163 * The array will be empty if the directory is empty. Returns
1164 * {@code null} if this abstract pathname does not denote a
1165 * directory, or if an I/O error occurs.
1166 *
1167 * @throws SecurityException
1168 * If a security manager exists and its {@link
1169 * SecurityManager#checkRead(String)} method denies read access to
1170 * the directory
1171 *
1172 * @since 1.2
1173 * @see java.nio.file.Files#newDirectoryStream(Path,String)
1174 */
1175 public File[] listFiles(FilenameFilter filter) {
1176 String ss[] = list();
1177 if (ss == null) return null;
1178 ArrayList<File> files = new ArrayList<>();
1179 for (String s : ss)
1180 if ((filter == null) || filter.accept(this, s))
1181 files.add(new File(s, this));
1182 return files.toArray(new File[files.size()]);
1183 }
1184
1185 /**
1186 * Returns an array of abstract pathnames denoting the files and
1187 * directories in the directory denoted by this abstract pathname that
1188 * satisfy the specified filter. The behavior of this method is the same
1189 * as that of the {@link #listFiles()} method, except that the pathnames in
1190 * the returned array must satisfy the filter. If the given {@code filter}
1191 * is {@code null} then all pathnames are accepted. Otherwise, a pathname
1192 * satisfies the filter if and only if the value {@code true} results when
1193 * the {@link FileFilter#accept FileFilter.accept(File)} method of the
1194 * filter is invoked on the pathname.
1195 *
1196 * @param filter
1197 * A file filter
1198 *
1199 * @return An array of abstract pathnames denoting the files and
1200 * directories in the directory denoted by this abstract pathname.
1201 * The array will be empty if the directory is empty. Returns
1202 * {@code null} if this abstract pathname does not denote a
1203 * directory, or if an I/O error occurs.
1204 *
1205 * @throws SecurityException
1206 * If a security manager exists and its {@link
1207 * SecurityManager#checkRead(String)} method denies read access to
1208 * the directory
1209 *
1210 * @since 1.2
1211 * @see java.nio.file.Files#newDirectoryStream(Path,java.nio.file.DirectoryStream.Filter)
1212 */
1213 public File[] listFiles(FileFilter filter) {
1214 String ss[] = list();
1215 if (ss == null) return null;
1216 ArrayList<File> files = new ArrayList<>();
1217 for (String s : ss) {
1218 File f = new File(s, this);
1219 if ((filter == null) || filter.accept(f))
1220 files.add(f);
1221 }
1222 return files.toArray(new File[files.size()]);
1223 }
1224
1225 /**
1226 * Creates the directory named by this abstract pathname.
1227 *
1228 * @return <code>true</code> if and only if the directory was
1229 * created; <code>false</code> otherwise
1230 *
1231 * @throws SecurityException
1232 * If a security manager exists and its <code>{@link
1233 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1234 * method does not permit the named directory to be created
1235 */
1236 public boolean mkdir() {
1237 SecurityManager security = System.getSecurityManager();
1238 if (security != null) {
1239 security.checkWrite(path);
1240 }
1241 return fs.createDirectory(this);
1242 }
1243
1244 /**
1245 * Creates the directory named by this abstract pathname, including any
1246 * necessary but nonexistent parent directories. Note that if this
1247 * operation fails it may have succeeded in creating some of the necessary
1248 * parent directories.
1249 *
1250 * @return <code>true</code> if and only if the directory was created,
1251 * along with all necessary parent directories; <code>false</code>
1252 * otherwise
1253 *
1254 * @throws SecurityException
1255 * If a security manager exists and its <code>{@link
1256 * java.lang.SecurityManager#checkRead(java.lang.String)}</code>
1257 * method does not permit verification of the existence of the
1258 * named directory and all necessary parent directories; or if
1259 * the <code>{@link
1260 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1261 * method does not permit the named directory and all necessary
1262 * parent directories to be created
1263 */
1264 public boolean mkdirs() {
1265 if (exists()) {
1266 return false;
1267 }
1268 if (mkdir()) {
1269 return true;
1270 }
1271 File canonFile = null;
1272 try {
1273 canonFile = getCanonicalFile();
1274 } catch (IOException e) {
1275 return false;
1276 }
1277
1278 File parent = canonFile.getParentFile();
1279 return (parent != null && (parent.mkdirs() || parent.exists()) &&
1280 canonFile.mkdir());
1281 }
1282
1283 /**
1284 * Renames the file denoted by this abstract pathname.
1285 *
1286 * <p> Many aspects of the behavior of this method are inherently
1287 * platform-dependent: The rename operation might not be able to move a
1288 * file from one filesystem to another, it might not be atomic, and it
1289 * might not succeed if a file with the destination abstract pathname
1290 * already exists. The return value should always be checked to make sure
1291 * that the rename operation was successful.
1292 *
1293 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1294 * java.nio.file.Files#move move} method to move or rename a file in a
1295 * platform independent manner.
1296 *
1297 * @param dest The new abstract pathname for the named file
1298 *
1299 * @return <code>true</code> if and only if the renaming succeeded;
1300 * <code>false</code> otherwise
1301 *
1302 * @throws SecurityException
1303 * If a security manager exists and its <code>{@link
1304 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1305 * method denies write access to either the old or new pathnames
1306 *
1307 * @throws NullPointerException
1308 * If parameter <code>dest</code> is <code>null</code>
1309 */
1310 public boolean renameTo(File dest) {
1311 SecurityManager security = System.getSecurityManager();
1312 if (security != null) {
1313 security.checkWrite(path);
1314 security.checkWrite(dest.path);
1315 }
1316 return fs.rename(this, dest);
1317 }
1318
1319 /**
1320 * Sets the last-modified time of the file or directory named by this
1321 * abstract pathname.
1322 *
1323 * <p> All platforms support file-modification times to the nearest second,
1324 * but some provide more precision. The argument will be truncated to fit
1325 * the supported precision. If the operation succeeds and no intervening
1326 * operations on the file take place, then the next invocation of the
1327 * <code>{@link #lastModified}</code> method will return the (possibly
1328 * truncated) <code>time</code> argument that was passed to this method.
1329 *
1330 * @param time The new last-modified time, measured in milliseconds since
1331 * the epoch (00:00:00 GMT, January 1, 1970)
1332 *
1333 * @return <code>true</code> if and only if the operation succeeded;
1334 * <code>false</code> otherwise
1335 *
1336 * @throws IllegalArgumentException If the argument is negative
1337 *
1338 * @throws SecurityException
1339 * If a security manager exists and its <code>{@link
1340 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1341 * method denies write access to the named file
1342 *
1343 * @since 1.2
1344 */
1345 public boolean setLastModified(long time) {
1346 if (time < 0) throw new IllegalArgumentException("Negative time");
1347 SecurityManager security = System.getSecurityManager();
1348 if (security != null) {
1349 security.checkWrite(path);
1350 }
1351 return fs.setLastModifiedTime(this, time);
1352 }
1353
1354 /**
1355 * Marks the file or directory named by this abstract pathname so that
1356 * only read operations are allowed. After invoking this method the file
1357 * or directory is guaranteed not to change until it is either deleted or
1358 * marked to allow write access. Whether or not a read-only file or
1359 * directory may be deleted depends upon the underlying system.
1360 *
1361 * @return <code>true</code> if and only if the operation succeeded;
1362 * <code>false</code> otherwise
1363 *
1364 * @throws SecurityException
1365 * If a security manager exists and its <code>{@link
1366 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1367 * method denies write access to the named file
1368 *
1369 * @since 1.2
1370 */
1371 public boolean setReadOnly() {
1372 SecurityManager security = System.getSecurityManager();
1373 if (security != null) {
1374 security.checkWrite(path);
1375 }
1376 return fs.setReadOnly(this);
1377 }
1378
1379 /**
1380 * Sets the owner's or everybody's write permission for this abstract
1381 * pathname.
1382 *
1383 * <p> The {@link java.nio.file.Files} class defines methods that operate on
1384 * file attributes including file permissions. This may be used when finer
1385 * manipulation of file permissions is required.
1386 *
1387 * @param writable
1388 * If <code>true</code>, sets the access permission to allow write
1389 * operations; if <code>false</code> to disallow write operations
1390 *
1391 * @param ownerOnly
1392 * If <code>true</code>, the write permission applies only to the
1393 * owner's write permission; otherwise, it applies to everybody. If
1394 * the underlying file system can not distinguish the owner's write
1395 * permission from that of others, then the permission will apply to
1396 * everybody, regardless of this value.
1397 *
1398 * @return <code>true</code> if and only if the operation succeeded. The
1399 * operation will fail if the user does not have permission to change
1400 * the access permissions of this abstract pathname.
1401 *
1402 * @throws SecurityException
1403 * If a security manager exists and its <code>{@link
1404 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1405 * method denies write access to the named file
1406 *
1407 * @since 1.6
1408 */
1409 public boolean setWritable(boolean writable, boolean ownerOnly) {
1410 SecurityManager security = System.getSecurityManager();
1411 if (security != null) {
1412 security.checkWrite(path);
1413 }
1414 return fs.setPermission(this, FileSystem.ACCESS_WRITE, writable, ownerOnly);
1415 }
1416
1417 /**
1418 * A convenience method to set the owner's write permission for this abstract
1419 * pathname.
1420 *
1421 * <p> An invocation of this method of the form <tt>file.setWritable(arg)</tt>
1422 * behaves in exactly the same way as the invocation
1423 *
1424 * <pre>
1425 * file.setWritable(arg, true) </pre>
1426 *
1427 * @param writable
1428 * If <code>true</code>, sets the access permission to allow write
1429 * operations; if <code>false</code> to disallow write operations
1430 *
1431 * @return <code>true</code> if and only if the operation succeeded. The
1432 * operation will fail if the user does not have permission to
1433 * change the access permissions of this abstract pathname.
1434 *
1435 * @throws SecurityException
1436 * If a security manager exists and its <code>{@link
1437 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1438 * method denies write access to the file
1439 *
1440 * @since 1.6
1441 */
1442 public boolean setWritable(boolean writable) {
1443 return setWritable(writable, true);
1444 }
1445
1446 /**
1447 * Sets the owner's or everybody's read permission for this abstract
1448 * pathname.
1449 *
1450 * <p> The {@link java.nio.file.Files} class defines methods that operate on
1451 * file attributes including file permissions. This may be used when finer
1452 * manipulation of file permissions is required.
1453 *
1454 * @param readable
1455 * If <code>true</code>, sets the access permission to allow read
1456 * operations; if <code>false</code> to disallow read operations
1457 *
1458 * @param ownerOnly
1459 * If <code>true</code>, the read permission applies only to the
1460 * owner's read permission; otherwise, it applies to everybody. If
1461 * the underlying file system can not distinguish the owner's read
1462 * permission from that of others, then the permission will apply to
1463 * everybody, regardless of this value.
1464 *
1465 * @return <code>true</code> if and only if the operation succeeded. The
1466 * operation will fail if the user does not have permission to
1467 * change the access permissions of this abstract pathname. If
1468 * <code>readable</code> is <code>false</code> and the underlying
1469 * file system does not implement a read permission, then the
1470 * operation will fail.
1471 *
1472 * @throws SecurityException
1473 * If a security manager exists and its <code>{@link
1474 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1475 * method denies write access to the file
1476 *
1477 * @since 1.6
1478 */
1479 public boolean setReadable(boolean readable, boolean ownerOnly) {
1480 SecurityManager security = System.getSecurityManager();
1481 if (security != null) {
1482 security.checkWrite(path);
1483 }
1484 return fs.setPermission(this, FileSystem.ACCESS_READ, readable, ownerOnly);
1485 }
1486
1487 /**
1488 * A convenience method to set the owner's read permission for this abstract
1489 * pathname.
1490 *
1491 * <p>An invocation of this method of the form <tt>file.setReadable(arg)</tt>
1492 * behaves in exactly the same way as the invocation
1493 *
1494 * <pre>
1495 * file.setReadable(arg, true) </pre>
1496 *
1497 * @param readable
1498 * If <code>true</code>, sets the access permission to allow read
1499 * operations; if <code>false</code> to disallow read operations
1500 *
1501 * @return <code>true</code> if and only if the operation succeeded. The
1502 * operation will fail if the user does not have permission to
1503 * change the access permissions of this abstract pathname. If
1504 * <code>readable</code> is <code>false</code> and the underlying
1505 * file system does not implement a read permission, then the
1506 * operation will fail.
1507 *
1508 * @throws SecurityException
1509 * If a security manager exists and its <code>{@link
1510 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1511 * method denies write access to the file
1512 *
1513 * @since 1.6
1514 */
1515 public boolean setReadable(boolean readable) {
1516 return setReadable(readable, true);
1517 }
1518
1519 /**
1520 * Sets the owner's or everybody's execute permission for this abstract
1521 * pathname.
1522 *
1523 * <p> The {@link java.nio.file.Files} class defines methods that operate on
1524 * file attributes including file permissions. This may be used when finer
1525 * manipulation of file permissions is required.
1526 *
1527 * @param executable
1528 * If <code>true</code>, sets the access permission to allow execute
1529 * operations; if <code>false</code> to disallow execute operations
1530 *
1531 * @param ownerOnly
1532 * If <code>true</code>, the execute permission applies only to the
1533 * owner's execute permission; otherwise, it applies to everybody.
1534 * If the underlying file system can not distinguish the owner's
1535 * execute permission from that of others, then the permission will
1536 * apply to everybody, regardless of this value.
1537 *
1538 * @return <code>true</code> if and only if the operation succeeded. The
1539 * operation will fail if the user does not have permission to
1540 * change the access permissions of this abstract pathname. If
1541 * <code>executable</code> is <code>false</code> and the underlying
1542 * file system does not implement an execute permission, then the
1543 * operation will fail.
1544 *
1545 * @throws SecurityException
1546 * If a security manager exists and its <code>{@link
1547 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1548 * method denies write access to the file
1549 *
1550 * @since 1.6
1551 */
1552 public boolean setExecutable(boolean executable, boolean ownerOnly) {
1553 SecurityManager security = System.getSecurityManager();
1554 if (security != null) {
1555 security.checkWrite(path);
1556 }
1557 return fs.setPermission(this, FileSystem.ACCESS_EXECUTE, executable, ownerOnly);
1558 }
1559
1560 /**
1561 * A convenience method to set the owner's execute permission for this abstract
1562 * pathname.
1563 *
1564 * <p>An invocation of this method of the form <tt>file.setExcutable(arg)</tt>
1565 * behaves in exactly the same way as the invocation
1566 *
1567 * <pre>
1568 * file.setExecutable(arg, true) </pre>
1569 *
1570 * @param executable
1571 * If <code>true</code>, sets the access permission to allow execute
1572 * operations; if <code>false</code> to disallow execute operations
1573 *
1574 * @return <code>true</code> if and only if the operation succeeded. The
1575 * operation will fail if the user does not have permission to
1576 * change the access permissions of this abstract pathname. If
1577 * <code>executable</code> is <code>false</code> and the underlying
1578 * file system does not implement an excute permission, then the
1579 * operation will fail.
1580 *
1581 * @throws SecurityException
1582 * If a security manager exists and its <code>{@link
1583 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1584 * method denies write access to the file
1585 *
1586 * @since 1.6
1587 */
1588 public boolean setExecutable(boolean executable) {
1589 return setExecutable(executable, true);
1590 }
1591
1592 /**
1593 * Tests whether the application can execute the file denoted by this
1594 * abstract pathname.
1595 *
1596 * @return <code>true</code> if and only if the abstract pathname exists
1597 * <em>and</em> the application is allowed to execute the file
1598 *
1599 * @throws SecurityException
1600 * If a security manager exists and its <code>{@link
1601 * java.lang.SecurityManager#checkExec(java.lang.String)}</code>
1602 * method denies execute access to the file
1603 *
1604 * @since 1.6
1605 */
1606 public boolean canExecute() {
1607 SecurityManager security = System.getSecurityManager();
1608 if (security != null) {
1609 security.checkExec(path);
1610 }
1611 return fs.checkAccess(this, FileSystem.ACCESS_EXECUTE);
1612 }
1613
1614
1615 /* -- Filesystem interface -- */
1616
1617 /**
1618 * List the available filesystem roots.
1619 *
1620 * <p> A particular Java platform may support zero or more
1621 * hierarchically-organized file systems. Each file system has a
1622 * {@code root} directory from which all other files in that file system
1623 * can be reached. Windows platforms, for example, have a root directory
1624 * for each active drive; UNIX platforms have a single root directory,
1625 * namely {@code "/"}. The set of available filesystem roots is affected
1626 * by various system-level operations such as the insertion or ejection of
1627 * removable media and the disconnecting or unmounting of physical or
1628 * virtual disk drives.
1629 *
1630 * <p> This method returns an array of {@code File} objects that denote the
1631 * root directories of the available filesystem roots. It is guaranteed
1632 * that the canonical pathname of any file physically present on the local
1633 * machine will begin with one of the roots returned by this method.
1634 *
1635 * <p> The canonical pathname of a file that resides on some other machine
1636 * and is accessed via a remote-filesystem protocol such as SMB or NFS may
1637 * or may not begin with one of the roots returned by this method. If the
1638 * pathname of a remote file is syntactically indistinguishable from the
1639 * pathname of a local file then it will begin with one of the roots
1640 * returned by this method. Thus, for example, {@code File} objects
1641 * denoting the root directories of the mapped network drives of a Windows
1642 * platform will be returned by this method, while {@code File} objects
1643 * containing UNC pathnames will not be returned by this method.
1644 *
1645 * <p> Unlike most methods in this class, this method does not throw
1646 * security exceptions. If a security manager exists and its {@link
1647 * SecurityManager#checkRead(String)} method denies read access to a
1648 * particular root directory, then that directory will not appear in the
1649 * result.
1650 *
1651 * @return An array of {@code File} objects denoting the available
1652 * filesystem roots, or {@code null} if the set of roots could not
1653 * be determined. The array will be empty if there are no
1654 * filesystem roots.
1655 *
1656 * @since 1.2
1657 * @see java.nio.file.FileStore
1658 */
1659 public static File[] listRoots() {
1660 return fs.listRoots();
1661 }
1662
1663
1664 /* -- Disk usage -- */
1665
1666 /**
1667 * Returns the size of the partition <a href="#partName">named</a> by this
1668 * abstract pathname.
1669 *
1670 * @return The size, in bytes, of the partition or <tt>0L</tt> if this
1671 * abstract pathname does not name a partition
1672 *
1673 * @throws SecurityException
1674 * If a security manager has been installed and it denies
1675 * {@link RuntimePermission}<tt>("getFileSystemAttributes")</tt>
1676 * or its {@link SecurityManager#checkRead(String)} method denies
1677 * read access to the file named by this abstract pathname
1678 *
1679 * @since 1.6
1680 */
1681 public long getTotalSpace() {
1682 SecurityManager sm = System.getSecurityManager();
1683 if (sm != null) {
1684 sm.checkPermission(new RuntimePermission("getFileSystemAttributes"));
1685 sm.checkRead(path);
1686 }
1687 return fs.getSpace(this, FileSystem.SPACE_TOTAL);
1688 }
1689
1690 /**
1691 * Returns the number of unallocated bytes in the partition <a
1692 * href="#partName">named</a> by this abstract path name.
1693 *
1694 * <p> The returned number of unallocated bytes is a hint, but not
1695 * a guarantee, that it is possible to use most or any of these
1696 * bytes. The number of unallocated bytes is most likely to be
1697 * accurate immediately after this call. It is likely to be made
1698 * inaccurate by any external I/O operations including those made
1699 * on the system outside of this virtual machine. This method
1700 * makes no guarantee that write operations to this file system
1701 * will succeed.
1702 *
1703 * @return The number of unallocated bytes on the partition <tt>0L</tt>
1704 * if the abstract pathname does not name a partition. This
1705 * value will be less than or equal to the total file system size
1706 * returned by {@link #getTotalSpace}.
1707 *
1708 * @throws SecurityException
1709 * If a security manager has been installed and it denies
1710 * {@link RuntimePermission}<tt>("getFileSystemAttributes")</tt>
1711 * or its {@link SecurityManager#checkRead(String)} method denies
1712 * read access to the file named by this abstract pathname
1713 *
1714 * @since 1.6
1715 */
1716 public long getFreeSpace() {
1717 SecurityManager sm = System.getSecurityManager();
1718 if (sm != null) {
1719 sm.checkPermission(new RuntimePermission("getFileSystemAttributes"));
1720 sm.checkRead(path);
1721 }
1722 return fs.getSpace(this, FileSystem.SPACE_FREE);
1723 }
1724
1725 /**
1726 * Returns the number of bytes available to this virtual machine on the
1727 * partition <a href="#partName">named</a> by this abstract pathname. When
1728 * possible, this method checks for write permissions and other operating
1729 * system restrictions and will therefore usually provide a more accurate
1730 * estimate of how much new data can actually be written than {@link
1731 * #getFreeSpace}.
1732 *
1733 * <p> The returned number of available bytes is a hint, but not a
1734 * guarantee, that it is possible to use most or any of these bytes. The
1735 * number of unallocated bytes is most likely to be accurate immediately
1736 * after this call. It is likely to be made inaccurate by any external
1737 * I/O operations including those made on the system outside of this
1738 * virtual machine. This method makes no guarantee that write operations
1739 * to this file system will succeed.
1740 *
1741 * @return The number of available bytes on the partition or <tt>0L</tt>
1742 * if the abstract pathname does not name a partition. On
1743 * systems where this information is not available, this method
1744 * will be equivalent to a call to {@link #getFreeSpace}.
1745 *
1746 * @throws SecurityException
1747 * If a security manager has been installed and it denies
1748 * {@link RuntimePermission}<tt>("getFileSystemAttributes")</tt>
1749 * or its {@link SecurityManager#checkRead(String)} method denies
1750 * read access to the file named by this abstract pathname
1751 *
1752 * @since 1.6
1753 */
1754 public long getUsableSpace() {
1755 SecurityManager sm = System.getSecurityManager();
1756 if (sm != null) {
1757 sm.checkPermission(new RuntimePermission("getFileSystemAttributes"));
1758 sm.checkRead(path);
1759 }
1760 return fs.getSpace(this, FileSystem.SPACE_USABLE);
1761 }
1762
1763 /* -- Temporary files -- */
1764
1765 private static class TempDirectory {
1766 private TempDirectory() { }
1767
1768 // temporary directory location
1769 private static final File tmpdir = new File(fs.normalize(AccessController
1770 .doPrivileged(new GetPropertyAction("java.io.tmpdir"))));
1771 static File location() {
1772 return tmpdir;
1773 }
1774
1775 // file name generation
1776 private static final SecureRandom random = new SecureRandom();
1777 static File generateFile(String prefix, String suffix, File dir) {
1778 long n = random.nextLong();
1779 if (n == Long.MIN_VALUE) {
1780 n = 0; // corner case
1781 } else {
1782 n = Math.abs(n);
1783 }
1784 return new File(dir, prefix + Long.toString(n) + suffix);
1785 }
1786 }
1787
1788 /**
1789 * <p> Creates a new empty file in the specified directory, using the
1790 * given prefix and suffix strings to generate its name. If this method
1791 * returns successfully then it is guaranteed that:
1792 *
1793 * <ol>
1794 * <li> The file denoted by the returned abstract pathname did not exist
1795 * before this method was invoked, and
1796 * <li> Neither this method nor any of its variants will return the same
1797 * abstract pathname again in the current invocation of the virtual
1798 * machine.
1799 * </ol>
1800 *
1801 * This method provides only part of a temporary-file facility. To arrange
1802 * for a file created by this method to be deleted automatically, use the
1803 * <code>{@link #deleteOnExit}</code> method.
1804 *
1805 * <p> The <code>prefix</code> argument must be at least three characters
1806 * long. It is recommended that the prefix be a short, meaningful string
1807 * such as <code>"hjb"</code> or <code>"mail"</code>. The
1808 * <code>suffix</code> argument may be <code>null</code>, in which case the
1809 * suffix <code>".tmp"</code> will be used.
1810 *
1811 * <p> To create the new file, the prefix and the suffix may first be
1812 * adjusted to fit the limitations of the underlying platform. If the
1813 * prefix is too long then it will be truncated, but its first three
1814 * characters will always be preserved. If the suffix is too long then it
1815 * too will be truncated, but if it begins with a period character
1816 * (<code>'.'</code>) then the period and the first three characters
1817 * following it will always be preserved. Once these adjustments have been
1818 * made the name of the new file will be generated by concatenating the
1819 * prefix, five or more internally-generated characters, and the suffix.
1820 *
1821 * <p> If the <code>directory</code> argument is <code>null</code> then the
1822 * system-dependent default temporary-file directory will be used. The
1823 * default temporary-file directory is specified by the system property
1824 * <code>java.io.tmpdir</code>. On UNIX systems the default value of this
1825 * property is typically <code>"/tmp"</code> or <code>"/var/tmp"</code>; on
1826 * Microsoft Windows systems it is typically <code>"C:\\WINNT\\TEMP"</code>. A different
1827 * value may be given to this system property when the Java virtual machine
1828 * is invoked, but programmatic changes to this property are not guaranteed
1829 * to have any effect upon the temporary directory used by this method.
1830 *
1831 * @param prefix The prefix string to be used in generating the file's
1832 * name; must be at least three characters long
1833 *
1834 * @param suffix The suffix string to be used in generating the file's
1835 * name; may be <code>null</code>, in which case the
1836 * suffix <code>".tmp"</code> will be used
1837 *
1838 * @param directory The directory in which the file is to be created, or
1839 * <code>null</code> if the default temporary-file
1840 * directory is to be used
1841 *
1842 * @return An abstract pathname denoting a newly-created empty file
1843 *
1844 * @throws IllegalArgumentException
1845 * If the <code>prefix</code> argument contains fewer than three
1846 * characters
1847 *
1848 * @throws IOException If a file could not be created
1849 *
1850 * @throws SecurityException
1851 * If a security manager exists and its <code>{@link
1852 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1853 * method does not allow a file to be created
1854 *
1855 * @since 1.2
1856 */
1857 public static File createTempFile(String prefix, String suffix,
1858 File directory)
1859 throws IOException
1860 {
1861 if (prefix.length() < 3)
1862 throw new IllegalArgumentException("Prefix string too short");
1863 if (suffix == null)
1864 suffix = ".tmp";
1865
1866 File tmpdir = (directory != null) ? directory : TempDirectory.location();
1867 SecurityManager sm = System.getSecurityManager();
1868 File f;
1869 do {
1870 f = TempDirectory.generateFile(prefix, suffix, tmpdir);
1871 if (sm != null) {
1872 try {
1873 sm.checkWrite(f.getPath());
1874 } catch (SecurityException se) {
1875 // don't reveal temporary directory location
1876 if (directory == null)
1877 throw new SecurityException("Unable to create temporary file");
1878 throw se;
1879 }
1880 }
1881 } while (!fs.createFileExclusively(f.getPath()));
1882 return f;
1883 }
1884
1885 /**
1886 * Creates an empty file in the default temporary-file directory, using
1887 * the given prefix and suffix to generate its name. Invoking this method
1888 * is equivalent to invoking <code>{@link #createTempFile(java.lang.String,
1889 * java.lang.String, java.io.File)
1890 * createTempFile(prefix, suffix, null)}</code>.
1891 *
1892 * <p> The {@link
1893 * java.nio.file.Files#createTempFile(String,String,java.nio.file.attribute.FileAttribute[])
1894 * Files.createTempFile} method provides an alternative method to create an
1895 * empty file in the temporary-file directory. Files created by that method
1896 * may have more restrictive access permissions to files created by this
1897 * method and so may be more suited to security-sensitive applications.
1898 *
1899 * @param prefix The prefix string to be used in generating the file's
1900 * name; must be at least three characters long
1901 *
1902 * @param suffix The suffix string to be used in generating the file's
1903 * name; may be <code>null</code>, in which case the
1904 * suffix <code>".tmp"</code> will be used
1905 *
1906 * @return An abstract pathname denoting a newly-created empty file
1907 *
1908 * @throws IllegalArgumentException
1909 * If the <code>prefix</code> argument contains fewer than three
1910 * characters
1911 *
1912 * @throws IOException If a file could not be created
1913 *
1914 * @throws SecurityException
1915 * If a security manager exists and its <code>{@link
1916 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1917 * method does not allow a file to be created
1918 *
1919 * @since 1.2
1920 * @see java.nio.file.Files#createTempDirectory(String,FileAttribute[])
1921 */
1922 public static File createTempFile(String prefix, String suffix)
1923 throws IOException
1924 {
1925 return createTempFile(prefix, suffix, null);
1926 }
1927
1928 /* -- Basic infrastructure -- */
1929
1930 /**
1931 * Compares two abstract pathnames lexicographically. The ordering
1932 * defined by this method depends upon the underlying system. On UNIX
1933 * systems, alphabetic case is significant in comparing pathnames; on Microsoft Windows
1934 * systems it is not.
1935 *
1936 * @param pathname The abstract pathname to be compared to this abstract
1937 * pathname
1938 *
1939 * @return Zero if the argument is equal to this abstract pathname, a
1940 * value less than zero if this abstract pathname is
1941 * lexicographically less than the argument, or a value greater
1942 * than zero if this abstract pathname is lexicographically
1943 * greater than the argument
1944 *
1945 * @since 1.2
1946 */
1947 public int compareTo(File pathname) {
1948 return fs.compare(this, pathname);
1949 }
1950
1951 /**
1952 * Tests this abstract pathname for equality with the given object.
1953 * Returns <code>true</code> if and only if the argument is not
1954 * <code>null</code> and is an abstract pathname that denotes the same file
1955 * or directory as this abstract pathname. Whether or not two abstract
1956 * pathnames are equal depends upon the underlying system. On UNIX
1957 * systems, alphabetic case is significant in comparing pathnames; on Microsoft Windows
1958 * systems it is not.
1959 *
1960 * @param obj The object to be compared with this abstract pathname
1961 *
1962 * @return <code>true</code> if and only if the objects are the same;
1963 * <code>false</code> otherwise
1964 */
1965 public boolean equals(Object obj) {
1966 if ((obj != null) && (obj instanceof File)) {
1967 return compareTo((File)obj) == 0;
1968 }
1969 return false;
1970 }
1971
1972 /**
1973 * Computes a hash code for this abstract pathname. Because equality of
1974 * abstract pathnames is inherently system-dependent, so is the computation
1975 * of their hash codes. On UNIX systems, the hash code of an abstract
1976 * pathname is equal to the exclusive <em>or</em> of the hash code
1977 * of its pathname string and the decimal value
1978 * <code>1234321</code>. On Microsoft Windows systems, the hash
1979 * code is equal to the exclusive <em>or</em> of the hash code of
1980 * its pathname string converted to lower case and the decimal
1981 * value <code>1234321</code>. Locale is not taken into account on
1982 * lowercasing the pathname string.
1983 *
1984 * @return A hash code for this abstract pathname
1985 */
1986 public int hashCode() {
1987 return fs.hashCode(this);
1988 }
1989
1990 /**
1991 * Returns the pathname string of this abstract pathname. This is just the
1992 * string returned by the <code>{@link #getPath}</code> method.
1993 *
1994 * @return The string form of this abstract pathname
1995 */
1996 public String toString() {
1997 return getPath();
1998 }
1999
2000 /**
2001 * WriteObject is called to save this filename.
2002 * The separator character is saved also so it can be replaced
2003 * in case the path is reconstituted on a different host type.
2004 * <p>
2005 * @serialData Default fields followed by separator character.
2006 */
2007 private synchronized void writeObject(java.io.ObjectOutputStream s)
2008 throws IOException
2009 {
2010 s.defaultWriteObject();
2011 s.writeChar(this.separatorChar); // Add the separator character
2012 }
2013
2014 /**
2015 * readObject is called to restore this filename.
2016 * The original separator character is read. If it is different
2017 * than the separator character on this system, then the old separator
2018 * is replaced by the local separator.
2019 */
2020 private synchronized void readObject(java.io.ObjectInputStream s)
2021 throws IOException, ClassNotFoundException
2022 {
2023 ObjectInputStream.GetField fields = s.readFields();
2024 String pathField = (String)fields.get("path", null);
2025 char sep = s.readChar(); // read the previous separator char
2026 if (sep != separatorChar)
2027 pathField = pathField.replace(sep, separatorChar);
2028 this.path = fs.normalize(pathField);
2029 this.prefixLength = fs.prefixLength(this.path);
2030 }
2031
2032 /** use serialVersionUID from JDK 1.0.2 for interoperability */
2033 private static final long serialVersionUID = 301077366599181567L;
2034
2035 // -- Integration with java.nio.file --
2036
2037 private volatile transient Path filePath;
2038
2039 /**
2040 * Returns a {@link Path java.nio.file.Path} object constructed from the
2041 * this abstract path. The resulting {@code Path} is associated with the
2042 * {@link java.nio.file.FileSystems#getDefault default-filesystem}.
2043 *
2044 * <p> The first invocation of this method works as if invoking it were
2045 * equivalent to evaluating the expression:
2046 * <blockquote><pre>
2047 * {@link java.nio.file.FileSystems#getDefault FileSystems.getDefault}().{@link
2048 * java.nio.file.FileSystem#getPath getPath}(this.{@link #getPath getPath}());
2049 * </pre></blockquote>
2050 * Subsequent invocations of this method return the same {@code Path}.
2051 *
2052 * <p> If this abstract pathname is the empty abstract pathname then this
2053 * method returns a {@code Path} that may be used to access the current
2054 * user directory.
2055 *
2056 * @return a {@code Path} constructed from this abstract path
2057 *
2058 * @throws InvalidPathException
2059 * if a {@code Path} object cannot be constructed from the abstract
2060 * path (see {@link java.nio.file.FileSystem#getPath FileSystem.getPath})
2061 *
2062 * @since 1.7
2063 * @see Path#toFile
2064 */
2065 public Path toPath() {
2066 Path result = filePath;
2067 if (result == null) {
2068 synchronized (this) {
2069 result = filePath;
2070 if (result == null) {
2071 result = FileSystems.getDefault().getPath(path);
2072 filePath = result;
2073 }
2074 }
2075 }
2076 return result;
2077 }
2078 }