1 /*
2 * Copyright (c) 1994, 2012, 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.net.URI;
29 import java.net.URL;
30 import java.net.MalformedURLException;
31 import java.net.URISyntaxException;
32 import java.util.List;
33 import java.util.ArrayList;
34 import java.security.AccessController;
35 import java.security.SecureRandom;
36 import java.nio.file.Path;
37 import java.nio.file.FileSystems;
38 import sun.security.action.GetPropertyAction;
39
40 /**
41 * An abstract representation of file and directory pathnames.
42 *
43 * <p> User interfaces and operating systems use system-dependent <em>pathname
44 * strings</em> to name files and directories. This class presents an
45 * abstract, system-independent view of hierarchical pathnames. An
46 * <em>abstract pathname</em> has two components:
47 *
48 * <ol>
49 * <li> An optional system-dependent <em>prefix</em> string,
50 * such as a disk-drive specifier, <code>"/"</code> for the UNIX root
51 * directory, or <code>"\\\\"</code> for a Microsoft Windows UNC pathname, and
52 * <li> A sequence of zero or more string <em>names</em>.
53 * </ol>
54 *
55 * The first name in an abstract pathname may be a directory name or, in the
56 * case of Microsoft Windows UNC pathnames, a hostname. Each subsequent name
57 * in an abstract pathname denotes a directory; the last name may denote
58 * either a directory or a file. The <em>empty</em> abstract pathname has no
59 * prefix and an empty name sequence.
60 *
61 * <p> The conversion of a pathname string to or from an abstract pathname is
62 * inherently system-dependent. When an abstract pathname is converted into a
63 * pathname string, each name is separated from the next by a single copy of
64 * the default <em>separator character</em>. The default name-separator
65 * character is defined by the system property <code>file.separator</code>, and
66 * is made available in the public static fields <code>{@link
67 * #separator}</code> and <code>{@link #separatorChar}</code> of this class.
68 * When a pathname string is converted into an abstract pathname, the names
69 * within it may be separated by the default name-separator character or by any
70 * other name-separator character that is supported by the underlying system.
71 *
72 * <p> A pathname, whether abstract or in string form, may be either
73 * <em>absolute</em> or <em>relative</em>. An absolute pathname is complete in
74 * that no other information is required in order to locate the file that it
75 * denotes. A relative pathname, in contrast, must be interpreted in terms of
76 * information taken from some other pathname. By default the classes in the
77 * <code>java.io</code> package always resolve relative pathnames against the
78 * current user directory. This directory is named by the system property
79 * <code>user.dir</code>, and is typically the directory in which the Java
80 * virtual machine was invoked.
81 *
82 * <p> The <em>parent</em> of an abstract pathname may be obtained by invoking
83 * the {@link #getParent} method of this class and consists of the pathname's
84 * prefix and each name in the pathname's name sequence except for the last.
85 * Each directory's absolute pathname is an ancestor of any <tt>File</tt>
86 * object with an absolute abstract pathname which begins with the directory's
87 * absolute pathname. For example, the directory denoted by the abstract
88 * pathname <tt>"/usr"</tt> is an ancestor of the directory denoted by the
89 * pathname <tt>"/usr/local/bin"</tt>.
90 *
91 * <p> The prefix concept is used to handle root directories on UNIX platforms,
92 * and drive specifiers, root directories and UNC pathnames on Microsoft Windows platforms,
93 * as follows:
94 *
95 * <ul>
96 *
97 * <li> For UNIX platforms, the prefix of an absolute pathname is always
98 * <code>"/"</code>. Relative pathnames have no prefix. The abstract pathname
99 * denoting the root directory has the prefix <code>"/"</code> and an empty
100 * name sequence.
101 *
102 * <li> For Microsoft Windows platforms, the prefix of a pathname that contains a drive
103 * specifier consists of the drive letter followed by <code>":"</code> and
104 * possibly followed by <code>"\\"</code> if the pathname is absolute. The
105 * prefix of a UNC pathname is <code>"\\\\"</code>; the hostname and the share
106 * name are the first two names in the name sequence. A relative pathname that
107 * does not specify a drive has no prefix.
108 *
109 * </ul>
110 *
111 * <p> Instances of this class may or may not denote an actual file-system
112 * object such as a file or a directory. If it does denote such an object
113 * then that object resides in a <i>partition</i>. A partition is an
114 * operating system-specific portion of storage for a file system. A single
115 * storage device (e.g. a physical disk-drive, flash memory, CD-ROM) may
116 * contain multiple partitions. The object, if any, will reside on the
117 * partition <a name="partName">named</a> by some ancestor of the absolute
118 * form of this pathname.
119 *
120 * <p> A file system may implement restrictions to certain operations on the
121 * actual file-system object, such as reading, writing, and executing. These
122 * restrictions are collectively known as <i>access permissions</i>. The file
123 * system may have multiple sets of access permissions on a single object.
124 * For example, one set may apply to the object's <i>owner</i>, and another
125 * may apply to all other users. The access permissions on an object may
126 * cause some methods in this class to fail.
127 *
128 * <p> Instances of the <code>File</code> class are immutable; that is, once
129 * created, the abstract pathname represented by a <code>File</code> object
130 * will never change.
131 *
132 * <h4>Interoperability with {@code java.nio.file} package</h4>
133 *
134 * <p> The <a href="../../java/nio/file/package-summary.html">{@code java.nio.file}</a>
135 * package defines interfaces and classes for the Java virtual machine to access
136 * files, file attributes, and file systems. This API may be used to overcome
137 * many of the limitations of the {@code java.io.File} class.
138 * The {@link #toPath toPath} method may be used to obtain a {@link
139 * Path} that uses the abstract path represented by a {@code File} object to
140 * locate a file. The resulting {@code Path} may be used with the {@link
141 * java.nio.file.Files} class to provide more efficient and extensive access to
142 * additional file operations, file attributes, and I/O exceptions to help
143 * diagnose errors when an operation on a file fails.
144 *
145 * @author unascribed
146 * @since JDK1.0
147 */
148
149 public class File
150 implements Serializable, Comparable<File>
151 {
152
153 /**
154 * The FileSystem object representing the platform's local file system.
155 */
156 private static final FileSystem fs = FileSystem.getFileSystem();
157
158 /**
159 * This abstract pathname's normalized pathname string. A normalized
160 * pathname string uses the default name-separator character and does not
161 * contain any duplicate or redundant separators.
162 *
163 * @serial
164 */
165 private final String path;
166
167 /**
168 * The length of this abstract pathname's prefix, or zero if it has no
169 * prefix.
170 */
171 private final transient int prefixLength;
172
173 /**
174 * Returns the length of this abstract pathname's prefix.
175 * For use by FileSystem classes.
176 */
177 int getPrefixLength() {
178 return prefixLength;
179 }
180
181 /**
182 * The system-dependent default name-separator character. This field is
183 * initialized to contain the first character of the value of the system
184 * property <code>file.separator</code>. On UNIX systems the value of this
185 * field is <code>'/'</code>; on Microsoft Windows systems it is <code>'\\'</code>.
186 *
187 * @see java.lang.System#getProperty(java.lang.String)
188 */
189 public static final char separatorChar = fs.getSeparator();
190
191 /**
192 * The system-dependent default name-separator character, represented as a
193 * string for convenience. This string contains a single character, namely
194 * <code>{@link #separatorChar}</code>.
195 */
196 public static final String separator = "" + separatorChar;
197
198 /**
199 * The system-dependent path-separator character. This field is
200 * initialized to contain the first character of the value of the system
201 * property <code>path.separator</code>. This character is used to
202 * separate filenames in a sequence of files given as a <em>path list</em>.
203 * On UNIX systems, this character is <code>':'</code>; on Microsoft Windows systems it
204 * is <code>';'</code>.
205 *
206 * @see java.lang.System#getProperty(java.lang.String)
207 */
208 public static final char pathSeparatorChar = fs.getPathSeparator();
209
210 /**
211 * The system-dependent path-separator character, represented as a string
212 * for convenience. This string contains a single character, namely
213 * <code>{@link #pathSeparatorChar}</code>.
214 */
215 public static final String pathSeparator = "" + pathSeparatorChar;
216
217
218 /* -- Constructors -- */
219
220 /**
221 * Internal constructor for already-normalized pathname strings.
222 */
223 private File(String pathname, int prefixLength) {
224 this.path = pathname;
225 this.prefixLength = prefixLength;
226 }
227
228 /**
229 * Internal constructor for already-normalized pathname strings.
230 * The parameter order is used to disambiguate this method from the
231 * public(File, String) constructor.
232 */
233 private File(String child, File parent) {
234 assert parent.path != null;
235 assert (!parent.path.equals(""));
236 this.path = fs.resolve(parent.path, child);
237 this.prefixLength = parent.prefixLength;
238 }
239
240 /**
241 * Creates a new <code>File</code> instance by converting the given
242 * pathname string into an abstract pathname. If the given string is
243 * the empty string, then the result is the empty abstract pathname.
244 *
245 * @param pathname A pathname string
246 * @throws NullPointerException
247 * If the <code>pathname</code> argument is <code>null</code>
248 */
249 public File(String pathname) {
250 if (pathname == null) {
251 throw new NullPointerException();
252 }
253 this.path = fs.normalize(pathname);
254 this.prefixLength = fs.prefixLength(this.path);
255 }
256
257 /* Note: The two-argument File constructors do not interpret an empty
258 parent abstract pathname as the current user directory. An empty parent
259 instead causes the child to be resolved against the system-dependent
260 directory defined by the FileSystem.getDefaultParent method. On Unix
261 this default is "/", while on Microsoft Windows it is "\\". This is required for
262 compatibility with the original behavior of this class. */
263
264 /**
265 * Creates a new <code>File</code> instance from a parent pathname string
266 * and a child pathname string.
267 *
268 * <p> If <code>parent</code> is <code>null</code> then the new
269 * <code>File</code> instance is created as if by invoking the
270 * single-argument <code>File</code> constructor on the given
271 * <code>child</code> pathname string.
272 *
273 * <p> Otherwise the <code>parent</code> pathname string is taken to denote
274 * a directory, and the <code>child</code> pathname string is taken to
275 * denote either a directory or a file. If the <code>child</code> pathname
276 * string is absolute then it is converted into a relative pathname in a
277 * system-dependent way. If <code>parent</code> is the empty string then
278 * the new <code>File</code> instance is created by converting
279 * <code>child</code> into an abstract pathname and resolving the result
280 * against a system-dependent default directory. Otherwise each pathname
281 * string is converted into an abstract pathname and the child abstract
282 * pathname is resolved against the parent.
283 *
284 * @param parent The parent pathname string
285 * @param child The child pathname string
286 * @throws NullPointerException
287 * If <code>child</code> is <code>null</code>
288 */
289 public File(String parent, String child) {
290 if (child == null) {
291 throw new NullPointerException();
292 }
293 if (parent != null) {
294 if (parent.equals("")) {
295 this.path = fs.resolve(fs.getDefaultParent(),
296 fs.normalize(child));
297 } else {
298 this.path = fs.resolve(fs.normalize(parent),
299 fs.normalize(child));
300 }
301 } else {
302 this.path = fs.normalize(child);
303 }
304 this.prefixLength = fs.prefixLength(this.path);
305 }
306
307 /**
308 * Creates a new <code>File</code> instance from a parent abstract
309 * pathname and a child pathname string.
310 *
311 * <p> If <code>parent</code> is <code>null</code> then the new
312 * <code>File</code> instance is created as if by invoking the
313 * single-argument <code>File</code> constructor on the given
314 * <code>child</code> pathname string.
315 *
316 * <p> Otherwise the <code>parent</code> abstract pathname is taken to
317 * denote a directory, and the <code>child</code> pathname string is taken
318 * to denote either a directory or a file. If the <code>child</code>
319 * pathname string is absolute then it is converted into a relative
320 * pathname in a system-dependent way. If <code>parent</code> is the empty
321 * abstract pathname then the new <code>File</code> instance is created by
322 * converting <code>child</code> into an abstract pathname and resolving
323 * the result against a system-dependent default directory. Otherwise each
324 * pathname string is converted into an abstract pathname and the child
325 * abstract pathname is resolved against the parent.
326 *
327 * @param parent The parent abstract pathname
328 * @param child The child pathname string
329 * @throws NullPointerException
330 * If <code>child</code> is <code>null</code>
331 */
332 public File(File parent, String child) {
333 if (child == null) {
334 throw new NullPointerException();
335 }
336 if (parent != null) {
337 if (parent.path.equals("")) {
338 this.path = fs.resolve(fs.getDefaultParent(),
339 fs.normalize(child));
340 } else {
341 this.path = fs.resolve(parent.path,
342 fs.normalize(child));
343 }
344 } else {
345 this.path = fs.normalize(child);
346 }
347 this.prefixLength = fs.prefixLength(this.path);
348 }
349
350 /**
351 * Creates a new <tt>File</tt> instance by converting the given
352 * <tt>file:</tt> URI into an abstract pathname.
353 *
354 * <p> The exact form of a <tt>file:</tt> URI is system-dependent, hence
355 * the transformation performed by this constructor is also
356 * system-dependent.
357 *
358 * <p> For a given abstract pathname <i>f</i> it is guaranteed that
359 *
360 * <blockquote><tt>
361 * new File(</tt><i> f</i><tt>.{@link #toURI() toURI}()).equals(</tt><i> f</i><tt>.{@link #getAbsoluteFile() getAbsoluteFile}())
362 * </tt></blockquote>
363 *
364 * so long as the original abstract pathname, the URI, and the new abstract
365 * pathname are all created in (possibly different invocations of) the same
366 * Java virtual machine. This relationship typically does not hold,
367 * however, when a <tt>file:</tt> URI that is created in a virtual machine
368 * on one operating system is converted into an abstract pathname in a
369 * virtual machine on a different operating system.
370 *
371 * @param uri
372 * An absolute, hierarchical URI with a scheme equal to
373 * <tt>"file"</tt>, a non-empty path component, and undefined
374 * authority, query, and fragment components
375 *
376 * @throws NullPointerException
377 * If <tt>uri</tt> is <tt>null</tt>
378 *
379 * @throws IllegalArgumentException
380 * If the preconditions on the parameter do not hold
381 *
382 * @see #toURI()
383 * @see java.net.URI
384 * @since 1.4
385 */
386 public File(URI uri) {
387
388 // Check our many preconditions
389 if (!uri.isAbsolute())
390 throw new IllegalArgumentException("URI is not absolute");
391 if (uri.isOpaque())
392 throw new IllegalArgumentException("URI is not hierarchical");
393 String scheme = uri.getScheme();
394 if ((scheme == null) || !scheme.equalsIgnoreCase("file"))
395 throw new IllegalArgumentException("URI scheme is not \"file\"");
396 if (uri.getAuthority() != null)
397 throw new IllegalArgumentException("URI has an authority component");
398 if (uri.getFragment() != null)
399 throw new IllegalArgumentException("URI has a fragment component");
400 if (uri.getQuery() != null)
401 throw new IllegalArgumentException("URI has a query component");
402 String p = uri.getPath();
403 if (p.equals(""))
404 throw new IllegalArgumentException("URI path component is empty");
405
406 // Okay, now initialize
407 p = fs.fromURIPath(p);
408 if (File.separatorChar != '/')
409 p = p.replace('/', File.separatorChar);
410 this.path = fs.normalize(p);
411 this.prefixLength = fs.prefixLength(this.path);
412 }
413
414
415 /* -- Path-component accessors -- */
416
417 /**
418 * Returns the name of the file or directory denoted by this abstract
419 * pathname. This is just the last name in the pathname's name
420 * sequence. If the pathname's name sequence is empty, then the empty
421 * string is returned.
422 *
423 * @return The name of the file or directory denoted by this abstract
424 * pathname, or the empty string if this pathname's name sequence
425 * is empty
426 */
427 public String getName() {
428 int index = path.lastIndexOf(separatorChar);
429 if (index < prefixLength) return path.substring(prefixLength);
430 return path.substring(index + 1);
431 }
432
433 /**
434 * Returns the pathname string of this abstract pathname's parent, or
435 * <code>null</code> if this pathname does not name a parent directory.
436 *
437 * <p> The <em>parent</em> of an abstract pathname consists of the
438 * pathname's prefix, if any, and each name in the pathname's name
439 * sequence except for the last. If the name sequence is empty then
440 * the pathname does not name a parent directory.
441 *
442 * @return The pathname string of the parent directory named by this
443 * abstract pathname, or <code>null</code> if this pathname
444 * does not name a parent
445 */
446 public String getParent() {
447 int index = path.lastIndexOf(separatorChar);
448 if (index < prefixLength) {
449 if ((prefixLength > 0) && (path.length() > prefixLength))
450 return path.substring(0, prefixLength);
451 return null;
452 }
453 return path.substring(0, index);
454 }
455
456 /**
457 * Returns the abstract pathname of this abstract pathname's parent,
458 * or <code>null</code> if this pathname does not name a parent
459 * directory.
460 *
461 * <p> The <em>parent</em> of an abstract pathname consists of the
462 * pathname's prefix, if any, and each name in the pathname's name
463 * sequence except for the last. If the name sequence is empty then
464 * the pathname does not name a parent directory.
465 *
466 * @return The abstract pathname of the parent directory named by this
467 * abstract pathname, or <code>null</code> if this pathname
468 * does not name a parent
469 *
470 * @since 1.2
471 */
472 public File getParentFile() {
473 String p = this.getParent();
474 if (p == null) return null;
475 return new File(p, this.prefixLength);
476 }
477
478 /**
479 * Converts this abstract pathname into a pathname string. The resulting
480 * string uses the {@link #separator default name-separator character} to
481 * separate the names in the name sequence.
482 *
483 * @return The string form of this abstract pathname
484 */
485 public String getPath() {
486 return path;
487 }
488
489
490 /* -- Path operations -- */
491
492 /**
493 * Tests whether this abstract pathname is absolute. The definition of
494 * absolute pathname is system dependent. On UNIX systems, a pathname is
495 * absolute if its prefix is <code>"/"</code>. On Microsoft Windows systems, a
496 * pathname is absolute if its prefix is a drive specifier followed by
497 * <code>"\\"</code>, or if its prefix is <code>"\\\\"</code>.
498 *
499 * @return <code>true</code> if this abstract pathname is absolute,
500 * <code>false</code> otherwise
501 */
502 public boolean isAbsolute() {
503 return fs.isAbsolute(this);
504 }
505
506 /**
507 * Returns the absolute pathname string of this abstract pathname.
508 *
509 * <p> If this abstract pathname is already absolute, then the pathname
510 * string is simply returned as if by the <code>{@link #getPath}</code>
511 * method. If this abstract pathname is the empty abstract pathname then
512 * the pathname string of the current user directory, which is named by the
513 * system property <code>user.dir</code>, is returned. Otherwise this
514 * pathname is resolved in a system-dependent way. On UNIX systems, a
515 * relative pathname is made absolute by resolving it against the current
516 * user directory. On Microsoft Windows systems, a relative pathname is made absolute
517 * by resolving it against the current directory of the drive named by the
518 * pathname, if any; if not, it is resolved against the current user
519 * directory.
520 *
521 * @return The absolute pathname string denoting the same file or
522 * directory as this abstract pathname
523 *
524 * @throws SecurityException
525 * If a required system property value cannot be accessed.
526 *
527 * @see java.io.File#isAbsolute()
528 */
529 public String getAbsolutePath() {
530 return fs.resolve(this);
531 }
532
533 /**
534 * Returns the absolute form of this abstract pathname. Equivalent to
535 * <code>new File(this.{@link #getAbsolutePath})</code>.
536 *
537 * @return The absolute abstract pathname denoting the same file or
538 * directory as this abstract pathname
539 *
540 * @throws SecurityException
541 * If a required system property value cannot be accessed.
542 *
543 * @since 1.2
544 */
545 public File getAbsoluteFile() {
546 String absPath = getAbsolutePath();
547 return new File(absPath, fs.prefixLength(absPath));
548 }
549
550 /**
551 * Returns the canonical pathname string of this abstract pathname.
552 *
553 * <p> A canonical pathname is both absolute and unique. The precise
554 * definition of canonical form is system-dependent. This method first
555 * converts this pathname to absolute form if necessary, as if by invoking the
556 * {@link #getAbsolutePath} method, and then maps it to its unique form in a
557 * system-dependent way. This typically involves removing redundant names
558 * such as <tt>"."</tt> and <tt>".."</tt> from the pathname, resolving
559 * symbolic links (on UNIX platforms), and converting drive letters to a
560 * standard case (on Microsoft Windows platforms).
561 *
562 * <p> Every pathname that denotes an existing file or directory has a
563 * unique canonical form. Every pathname that denotes a nonexistent file
564 * or directory also has a unique canonical form. The canonical form of
565 * the pathname of a nonexistent file or directory may be different from
566 * the canonical form of the same pathname after the file or directory is
567 * created. Similarly, the canonical form of the pathname of an existing
568 * file or directory may be different from the canonical form of the same
569 * pathname after the file or directory is deleted.
570 *
571 * @return The canonical pathname string denoting the same file or
572 * directory as this abstract pathname
573 *
574 * @throws IOException
575 * If an I/O error occurs, which is possible because the
576 * construction of the canonical pathname may require
577 * filesystem queries
578 *
579 * @throws SecurityException
580 * If a required system property value cannot be accessed, or
581 * if a security manager exists and its <code>{@link
582 * java.lang.SecurityManager#checkRead}</code> method denies
583 * read access to the file
584 *
585 * @since JDK1.1
586 * @see Path#toRealPath
587 */
588 public String getCanonicalPath() throws IOException {
589 return fs.canonicalize(fs.resolve(this));
590 }
591
592 /**
593 * Returns the canonical form of this abstract pathname. Equivalent to
594 * <code>new File(this.{@link #getCanonicalPath})</code>.
595 *
596 * @return The canonical pathname string denoting the same file or
597 * directory as this abstract pathname
598 *
599 * @throws IOException
600 * If an I/O error occurs, which is possible because the
601 * construction of the canonical pathname may require
602 * filesystem queries
603 *
604 * @throws SecurityException
605 * If a required system property value cannot be accessed, or
606 * if a security manager exists and its <code>{@link
607 * java.lang.SecurityManager#checkRead}</code> method denies
608 * read access to the file
609 *
610 * @since 1.2
611 * @see Path#toRealPath
612 */
613 public File getCanonicalFile() throws IOException {
614 String canonPath = getCanonicalPath();
615 return new File(canonPath, fs.prefixLength(canonPath));
616 }
617
618 private static String slashify(String path, boolean isDirectory) {
619 String p = path;
620 if (File.separatorChar != '/')
621 p = p.replace(File.separatorChar, '/');
622 if (!p.startsWith("/"))
623 p = "/" + p;
624 if (!p.endsWith("/") && isDirectory)
625 p = p + "/";
626 return p;
627 }
628
629 /**
630 * Converts this abstract pathname into a <code>file:</code> URL. The
631 * exact form of the URL is system-dependent. If it can be determined that
632 * the file denoted by this abstract pathname is a directory, then the
633 * resulting URL will end with a slash.
634 *
635 * @return A URL object representing the equivalent file URL
636 *
637 * @throws MalformedURLException
638 * If the path cannot be parsed as a URL
639 *
640 * @see #toURI()
641 * @see java.net.URI
642 * @see java.net.URI#toURL()
643 * @see java.net.URL
644 * @since 1.2
645 *
646 * @deprecated This method does not automatically escape characters that
647 * are illegal in URLs. It is recommended that new code convert an
648 * abstract pathname into a URL by first converting it into a URI, via the
649 * {@link #toURI() toURI} method, and then converting the URI into a URL
650 * via the {@link java.net.URI#toURL() URI.toURL} method.
651 */
652 @Deprecated
653 public URL toURL() throws MalformedURLException {
654 return new URL("file", "", slashify(getAbsolutePath(), isDirectory()));
655 }
656
657 /**
658 * Constructs a <tt>file:</tt> URI that represents this abstract pathname.
659 *
660 * <p> The exact form of the URI is system-dependent. If it can be
661 * determined that the file denoted by this abstract pathname is a
662 * directory, then the resulting URI will end with a slash.
663 *
664 * <p> For a given abstract pathname <i>f</i>, it is guaranteed that
665 *
666 * <blockquote><tt>
667 * new {@link #File(java.net.URI) File}(</tt><i> f</i><tt>.toURI()).equals(</tt><i> f</i><tt>.{@link #getAbsoluteFile() getAbsoluteFile}())
668 * </tt></blockquote>
669 *
670 * so long as the original abstract pathname, the URI, and the new abstract
671 * pathname are all created in (possibly different invocations of) the same
672 * Java virtual machine. Due to the system-dependent nature of abstract
673 * pathnames, however, this relationship typically does not hold when a
674 * <tt>file:</tt> URI that is created in a virtual machine on one operating
675 * system is converted into an abstract pathname in a virtual machine on a
676 * different operating system.
677 *
678 * <p> Note that when this abstract pathname represents a UNC pathname then
679 * all components of the UNC (including the server name component) are encoded
680 * in the {@code URI} path. The authority component is undefined, meaning
681 * that it is represented as {@code null}. The {@link Path} class defines the
682 * {@link Path#toUri toUri} method to encode the server name in the authority
683 * component of the resulting {@code URI}. The {@link #toPath toPath} method
684 * may be used to obtain a {@code Path} representing this abstract pathname.
685 *
686 * @return An absolute, hierarchical URI with a scheme equal to
687 * <tt>"file"</tt>, a path representing this abstract pathname,
688 * and undefined authority, query, and fragment components
689 * @throws SecurityException If a required system property value cannot
690 * be accessed.
691 *
692 * @see #File(java.net.URI)
693 * @see java.net.URI
694 * @see java.net.URI#toURL()
695 * @since 1.4
696 */
697 public URI toURI() {
698 try {
699 File f = getAbsoluteFile();
700 String sp = slashify(f.getPath(), f.isDirectory());
701 if (sp.startsWith("//"))
702 sp = "//" + sp;
703 return new URI("file", null, sp, null);
704 } catch (URISyntaxException x) {
705 throw new Error(x); // Can't happen
706 }
707 }
708
709
710 /* -- Attribute accessors -- */
711
712 /**
713 * Tests whether the application can read the file denoted by this
714 * abstract pathname. On some platforms it may be possible to start the
715 * Java virtual machine with special privileges that allow it to read
716 * files that are marked as unreadable. Consequently this method may return
717 * {@code true} even though the file does not have read permissions.
718 *
719 * @return <code>true</code> if and only if the file specified by this
720 * abstract pathname exists <em>and</em> can be read by the
721 * application; <code>false</code> otherwise
722 *
723 * @throws SecurityException
724 * If a security manager exists and its <code>{@link
725 * java.lang.SecurityManager#checkRead(java.lang.String)}</code>
726 * method denies read access to the file
727 */
728 public boolean canRead() {
729 SecurityManager security = System.getSecurityManager();
730 if (security != null) {
731 security.checkRead(path);
732 }
733 return fs.checkAccess(this, FileSystem.ACCESS_READ);
734 }
735
736 /**
737 * Tests whether the application can modify the file denoted by this
738 * abstract pathname. On some platforms it may be possible to start the
739 * Java virtual machine with special privileges that allow it to modify
740 * files that are marked read-only. Consequently this method may return
741 * {@code true} even though the file is marked read-only.
742 *
743 * @return <code>true</code> if and only if the file system actually
744 * contains a file denoted by this abstract pathname <em>and</em>
745 * the application is allowed to write to the file;
746 * <code>false</code> otherwise.
747 *
748 * @throws SecurityException
749 * If a security manager exists and its <code>{@link
750 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
751 * method denies write access to the file
752 */
753 public boolean canWrite() {
754 SecurityManager security = System.getSecurityManager();
755 if (security != null) {
756 security.checkWrite(path);
757 }
758 return fs.checkAccess(this, FileSystem.ACCESS_WRITE);
759 }
760
761 /**
762 * Tests whether the file or directory denoted by this abstract pathname
763 * exists.
764 *
765 * @return <code>true</code> if and only if the file or directory denoted
766 * by this abstract pathname exists; <code>false</code> otherwise
767 *
768 * @throws SecurityException
769 * If a security manager exists and its <code>{@link
770 * java.lang.SecurityManager#checkRead(java.lang.String)}</code>
771 * method denies read access to the file or directory
772 */
773 public boolean exists() {
774 SecurityManager security = System.getSecurityManager();
775 if (security != null) {
776 security.checkRead(path);
777 }
778 return ((fs.getBooleanAttributes(this) & FileSystem.BA_EXISTS) != 0);
779 }
780
781 /**
782 * Tests whether the file denoted by this abstract pathname is a
783 * directory.
784 *
785 * <p> Where it is required to distinguish an I/O exception from the case
786 * that the file is not a directory, or where several attributes of the
787 * same file are required at the same time, then the {@link
788 * java.nio.file.Files#readAttributes(Path,Class,LinkOption[])
789 * Files.readAttributes} method may be used.
790 *
791 * @return <code>true</code> if and only if the file denoted by this
792 * abstract pathname exists <em>and</em> is a directory;
793 * <code>false</code> otherwise
794 *
795 * @throws SecurityException
796 * If a security manager exists and its <code>{@link
797 * java.lang.SecurityManager#checkRead(java.lang.String)}</code>
798 * method denies read access to the file
799 */
800 public boolean isDirectory() {
801 SecurityManager security = System.getSecurityManager();
802 if (security != null) {
803 security.checkRead(path);
804 }
805 return ((fs.getBooleanAttributes(this) & FileSystem.BA_DIRECTORY)
806 != 0);
807 }
808
809 /**
810 * Tests whether the file denoted by this abstract pathname is a normal
811 * file. A file is <em>normal</em> if it is not a directory and, in
812 * addition, satisfies other system-dependent criteria. Any non-directory
813 * file created by a Java application is guaranteed to be a normal file.
814 *
815 * <p> Where it is required to distinguish an I/O exception from the case
816 * that the file is not a normal file, or where several attributes of the
817 * same file are required at the same time, then the {@link
818 * java.nio.file.Files#readAttributes(Path,Class,LinkOption[])
819 * Files.readAttributes} method may be used.
820 *
821 * @return <code>true</code> if and only if the file denoted by this
822 * abstract pathname exists <em>and</em> is a normal file;
823 * <code>false</code> otherwise
824 *
825 * @throws SecurityException
826 * If a security manager exists and its <code>{@link
827 * java.lang.SecurityManager#checkRead(java.lang.String)}</code>
828 * method denies read access to the file
829 */
830 public boolean isFile() {
831 SecurityManager security = System.getSecurityManager();
832 if (security != null) {
833 security.checkRead(path);
834 }
835 return ((fs.getBooleanAttributes(this) & FileSystem.BA_REGULAR) != 0);
836 }
837
838 /**
839 * Tests whether the file named by this abstract pathname is a hidden
840 * file. The exact definition of <em>hidden</em> is system-dependent. On
841 * UNIX systems, a file is considered to be hidden if its name begins with
842 * a period character (<code>'.'</code>). On Microsoft Windows systems, a file is
843 * considered to be hidden if it has been marked as such in the filesystem.
844 *
845 * @return <code>true</code> if and only if the file denoted by this
846 * abstract pathname is hidden according to the conventions of the
847 * underlying platform
848 *
849 * @throws SecurityException
850 * If a security manager exists and its <code>{@link
851 * java.lang.SecurityManager#checkRead(java.lang.String)}</code>
852 * method denies read access to the file
853 *
854 * @since 1.2
855 */
856 public boolean isHidden() {
857 SecurityManager security = System.getSecurityManager();
858 if (security != null) {
859 security.checkRead(path);
860 }
861 return ((fs.getBooleanAttributes(this) & FileSystem.BA_HIDDEN) != 0);
862 }
863
864 /**
865 * Returns the time that the file denoted by this abstract pathname was
866 * last modified.
867 *
868 * <p> Where it is required to distinguish an I/O exception from the case
869 * where {@code 0L} is returned, or where several attributes of the
870 * same file are required at the same time, or where the time of last
871 * access or the creation time are required, then the {@link
872 * java.nio.file.Files#readAttributes(Path,Class,LinkOption[])
873 * Files.readAttributes} method may be used.
874 *
875 * @return A <code>long</code> value representing the time the file was
876 * last modified, measured in milliseconds since the epoch
877 * (00:00:00 GMT, January 1, 1970), or <code>0L</code> if the
878 * file does not exist or if an I/O error occurs
879 *
880 * @throws SecurityException
881 * If a security manager exists and its <code>{@link
882 * java.lang.SecurityManager#checkRead(java.lang.String)}</code>
883 * method denies read access to the file
884 */
885 public long lastModified() {
886 SecurityManager security = System.getSecurityManager();
887 if (security != null) {
888 security.checkRead(path);
889 }
890 return fs.getLastModifiedTime(this);
891 }
892
893 /**
894 * Returns the length of the file denoted by this abstract pathname.
895 * The return value is unspecified if this pathname denotes a directory.
896 *
897 * <p> Where it is required to distinguish an I/O exception from the case
898 * that {@code 0L} is returned, or where several attributes of the same file
899 * are required at the same time, then the {@link
900 * java.nio.file.Files#readAttributes(Path,Class,LinkOption[])
901 * Files.readAttributes} method may be used.
902 *
903 * @return The length, in bytes, of the file denoted by this abstract
904 * pathname, or <code>0L</code> if the file does not exist. Some
905 * operating systems may return <code>0L</code> for pathnames
906 * denoting system-dependent entities such as devices or pipes.
907 *
908 * @throws SecurityException
909 * If a security manager exists and its <code>{@link
910 * java.lang.SecurityManager#checkRead(java.lang.String)}</code>
911 * method denies read access to the file
912 */
913 public long length() {
914 SecurityManager security = System.getSecurityManager();
915 if (security != null) {
916 security.checkRead(path);
917 }
918 return fs.getLength(this);
919 }
920
921
922 /* -- File operations -- */
923
924 /**
925 * Atomically creates a new, empty file named by this abstract pathname if
926 * and only if a file with this name does not yet exist. The check for the
927 * existence of the file and the creation of the file if it does not exist
928 * are a single operation that is atomic with respect to all other
929 * filesystem activities that might affect the file.
930 * <P>
931 * Note: this method should <i>not</i> be used for file-locking, as
932 * the resulting protocol cannot be made to work reliably. The
933 * {@link java.nio.channels.FileLock FileLock}
934 * facility should be used instead.
935 *
936 * @return <code>true</code> if the named file does not exist and was
937 * successfully created; <code>false</code> if the named file
938 * already exists
939 *
940 * @throws IOException
941 * If an I/O error occurred
942 *
943 * @throws SecurityException
944 * If a security manager exists and its <code>{@link
945 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
946 * method denies write access to the file
947 *
948 * @since 1.2
949 */
950 public boolean createNewFile() throws IOException {
951 SecurityManager security = System.getSecurityManager();
952 if (security != null) security.checkWrite(path);
953 return fs.createFileExclusively(path);
954 }
955
956 /**
957 * Deletes the file or directory denoted by this abstract pathname. If
958 * this pathname denotes a directory, then the directory must be empty in
959 * order to be deleted.
960 *
961 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
962 * java.nio.file.Files#delete(Path) delete} method to throw an {@link IOException}
963 * when a file cannot be deleted. This is useful for error reporting and to
964 * diagnose why a file cannot be deleted.
965 *
966 * @return <code>true</code> if and only if the file or directory is
967 * successfully deleted; <code>false</code> otherwise
968 *
969 * @throws SecurityException
970 * If a security manager exists and its <code>{@link
971 * java.lang.SecurityManager#checkDelete}</code> method denies
972 * delete access to the file
973 */
974 public boolean delete() {
975 SecurityManager security = System.getSecurityManager();
976 if (security != null) {
977 security.checkDelete(path);
978 }
979 return fs.delete(this);
980 }
981
982 /**
983 * Requests that the file or directory denoted by this abstract
984 * pathname be deleted when the virtual machine terminates.
985 * Files (or directories) are deleted in the reverse order that
986 * they are registered. Invoking this method to delete a file or
987 * directory that is already registered for deletion has no effect.
988 * Deletion will be attempted only for normal termination of the
989 * virtual machine, as defined by the Java Language Specification.
990 *
991 * <p> Once deletion has been requested, it is not possible to cancel the
992 * request. This method should therefore be used with care.
993 *
994 * <P>
995 * Note: this method should <i>not</i> be used for file-locking, as
996 * the resulting protocol cannot be made to work reliably. The
997 * {@link java.nio.channels.FileLock FileLock}
998 * facility should be used instead.
999 *
1000 * @throws SecurityException
1001 * If a security manager exists and its <code>{@link
1002 * java.lang.SecurityManager#checkDelete}</code> method denies
1003 * delete access to the file
1004 *
1005 * @see #delete
1006 *
1007 * @since 1.2
1008 */
1009 public void deleteOnExit() {
1010 SecurityManager security = System.getSecurityManager();
1011 if (security != null) {
1012 security.checkDelete(path);
1013 }
1014 DeleteOnExitHook.add(path);
1015 }
1016
1017 /**
1018 * Returns an array of strings naming the files and directories in the
1019 * directory denoted by this abstract pathname.
1020 *
1021 * <p> If this abstract pathname does not denote a directory, then this
1022 * method returns {@code null}. Otherwise an array of strings is
1023 * returned, one for each file or directory in the directory. Names
1024 * denoting the directory itself and the directory's parent directory are
1025 * not included in the result. Each string is a file name rather than a
1026 * complete path.
1027 *
1028 * <p> There is no guarantee that the name strings in the resulting array
1029 * will appear in any specific order; they are not, in particular,
1030 * guaranteed to appear in alphabetical order.
1031 *
1032 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1033 * java.nio.file.Files#newDirectoryStream(Path) newDirectoryStream} method to
1034 * open a directory and iterate over the names of the files in the directory.
1035 * This may use less resources when working with very large directories, and
1036 * may be more responsive when working with remote directories.
1037 *
1038 * @return An array of strings naming the files and directories in the
1039 * directory denoted by this abstract pathname. The array will be
1040 * empty if the directory is empty. Returns {@code null} if
1041 * this abstract pathname does not denote a directory, or if an
1042 * I/O error occurs.
1043 *
1044 * @throws SecurityException
1045 * If a security manager exists and its {@link
1046 * SecurityManager#checkRead(String)} method denies read access to
1047 * the directory
1048 */
1049 public String[] list() {
1050 SecurityManager security = System.getSecurityManager();
1051 if (security != null) {
1052 security.checkRead(path);
1053 }
1054 return fs.list(this);
1055 }
1056
1057 /**
1058 * Returns an array of strings naming the files and directories in the
1059 * directory denoted by this abstract pathname that satisfy the specified
1060 * filter. The behavior of this method is the same as that of the
1061 * {@link #list()} method, except that the strings in the returned array
1062 * must satisfy the filter. If the given {@code filter} is {@code null}
1063 * then all names are accepted. Otherwise, a name satisfies the filter if
1064 * and only if the value {@code true} results when the {@link
1065 * FilenameFilter#accept FilenameFilter.accept(File, String)} method
1066 * of the filter is invoked on this abstract pathname and the name of a
1067 * file or directory in the directory that it denotes.
1068 *
1069 * @param filter
1070 * A filename filter
1071 *
1072 * @return An array of strings naming the files and directories in the
1073 * directory denoted by this abstract pathname that were accepted
1074 * by the given {@code filter}. The array will be empty if the
1075 * directory is empty or if no names were accepted by the filter.
1076 * Returns {@code null} if this abstract pathname does not denote
1077 * a directory, or if an I/O error occurs.
1078 *
1079 * @throws SecurityException
1080 * If a security manager exists and its {@link
1081 * SecurityManager#checkRead(String)} method denies read access to
1082 * the directory
1083 *
1084 * @see java.nio.file.Files#newDirectoryStream(Path,String)
1085 */
1086 public String[] list(FilenameFilter filter) {
1087 String names[] = list();
1088 if ((names == null) || (filter == null)) {
1089 return names;
1090 }
1091 List<String> v = new ArrayList<>();
1092 for (int i = 0 ; i < names.length ; i++) {
1093 if (filter.accept(this, names[i])) {
1094 v.add(names[i]);
1095 }
1096 }
1097 return v.toArray(new String[v.size()]);
1098 }
1099
1100 /**
1101 * Returns an array of abstract pathnames denoting the files in the
1102 * directory denoted by this abstract pathname.
1103 *
1104 * <p> If this abstract pathname does not denote a directory, then this
1105 * method returns {@code null}. Otherwise an array of {@code File} objects
1106 * is returned, one for each file or directory in the directory. Pathnames
1107 * denoting the directory itself and the directory's parent directory are
1108 * not included in the result. Each resulting abstract pathname is
1109 * constructed from this abstract pathname using the {@link #File(File,
1110 * String) File(File, String)} constructor. Therefore if this
1111 * pathname is absolute then each resulting pathname is absolute; if this
1112 * pathname is relative then each resulting pathname will be relative to
1113 * the same directory.
1114 *
1115 * <p> There is no guarantee that the name strings in the resulting array
1116 * will appear in any specific order; they are not, in particular,
1117 * guaranteed to appear in alphabetical order.
1118 *
1119 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1120 * java.nio.file.Files#newDirectoryStream(Path) newDirectoryStream} method
1121 * to open a directory and iterate over the names of the files in the
1122 * directory. This may use less resources when working with very large
1123 * directories.
1124 *
1125 * @return An array of abstract pathnames denoting the files and
1126 * directories in the directory denoted by this abstract pathname.
1127 * The array will be empty if the directory is empty. Returns
1128 * {@code null} if this abstract pathname does not denote a
1129 * directory, or if an I/O error occurs.
1130 *
1131 * @throws SecurityException
1132 * If a security manager exists and its {@link
1133 * SecurityManager#checkRead(String)} method denies read access to
1134 * the directory
1135 *
1136 * @since 1.2
1137 */
1138 public File[] listFiles() {
1139 String[] ss = list();
1140 if (ss == null) return null;
1141 int n = ss.length;
1142 File[] fs = new File[n];
1143 for (int i = 0; i < n; i++) {
1144 fs[i] = new File(ss[i], this);
1145 }
1146 return fs;
1147 }
1148
1149 /**
1150 * Returns an array of abstract pathnames denoting the files and
1151 * directories in the directory denoted by this abstract pathname that
1152 * satisfy the specified filter. The behavior of this method is the same
1153 * as that of the {@link #listFiles()} method, except that the pathnames in
1154 * the returned array must satisfy the filter. If the given {@code filter}
1155 * is {@code null} then all pathnames are accepted. Otherwise, a pathname
1156 * satisfies the filter if and only if the value {@code true} results when
1157 * the {@link FilenameFilter#accept
1158 * FilenameFilter.accept(File, String)} method of the filter is
1159 * invoked on this abstract pathname and the name of a file or directory in
1160 * the directory that it denotes.
1161 *
1162 * @param filter
1163 * A filename filter
1164 *
1165 * @return An array of abstract pathnames denoting the files and
1166 * directories in the directory denoted by this abstract pathname.
1167 * The array will be empty if the directory is empty. Returns
1168 * {@code null} if this abstract pathname does not denote a
1169 * directory, or if an I/O error occurs.
1170 *
1171 * @throws SecurityException
1172 * If a security manager exists and its {@link
1173 * SecurityManager#checkRead(String)} method denies read access to
1174 * the directory
1175 *
1176 * @since 1.2
1177 * @see java.nio.file.Files#newDirectoryStream(Path,String)
1178 */
1179 public File[] listFiles(FilenameFilter filter) {
1180 String ss[] = list();
1181 if (ss == null) return null;
1182 ArrayList<File> files = new ArrayList<>();
1183 for (String s : ss)
1184 if ((filter == null) || filter.accept(this, s))
1185 files.add(new File(s, this));
1186 return files.toArray(new File[files.size()]);
1187 }
1188
1189 /**
1190 * Returns an array of abstract pathnames denoting the files and
1191 * directories in the directory denoted by this abstract pathname that
1192 * satisfy the specified filter. The behavior of this method is the same
1193 * as that of the {@link #listFiles()} method, except that the pathnames in
1194 * the returned array must satisfy the filter. If the given {@code filter}
1195 * is {@code null} then all pathnames are accepted. Otherwise, a pathname
1196 * satisfies the filter if and only if the value {@code true} results when
1197 * the {@link FileFilter#accept FileFilter.accept(File)} method of the
1198 * filter is invoked on the pathname.
1199 *
1200 * @param filter
1201 * A file filter
1202 *
1203 * @return An array of abstract pathnames denoting the files and
1204 * directories in the directory denoted by this abstract pathname.
1205 * The array will be empty if the directory is empty. Returns
1206 * {@code null} if this abstract pathname does not denote a
1207 * directory, or if an I/O error occurs.
1208 *
1209 * @throws SecurityException
1210 * If a security manager exists and its {@link
1211 * SecurityManager#checkRead(String)} method denies read access to
1212 * the directory
1213 *
1214 * @since 1.2
1215 * @see java.nio.file.Files#newDirectoryStream(Path,java.nio.file.DirectoryStream.Filter)
1216 */
1217 public File[] listFiles(FileFilter filter) {
1218 String ss[] = list();
1219 if (ss == null) return null;
1220 ArrayList<File> files = new ArrayList<>();
1221 for (String s : ss) {
1222 File f = new File(s, this);
1223 if ((filter == null) || filter.accept(f))
1224 files.add(f);
1225 }
1226 return files.toArray(new File[files.size()]);
1227 }
1228
1229 /**
1230 * Creates the directory named by this abstract pathname.
1231 *
1232 * @return <code>true</code> if and only if the directory was
1233 * created; <code>false</code> otherwise
1234 *
1235 * @throws SecurityException
1236 * If a security manager exists and its <code>{@link
1237 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1238 * method does not permit the named directory to be created
1239 */
1240 public boolean mkdir() {
1241 SecurityManager security = System.getSecurityManager();
1242 if (security != null) {
1243 security.checkWrite(path);
1244 }
1245 return fs.createDirectory(this);
1246 }
1247
1248 /**
1249 * Creates the directory named by this abstract pathname, including any
1250 * necessary but nonexistent parent directories. Note that if this
1251 * operation fails it may have succeeded in creating some of the necessary
1252 * parent directories.
1253 *
1254 * @return <code>true</code> if and only if the directory was created,
1255 * along with all necessary parent directories; <code>false</code>
1256 * otherwise
1257 *
1258 * @throws SecurityException
1259 * If a security manager exists and its <code>{@link
1260 * java.lang.SecurityManager#checkRead(java.lang.String)}</code>
1261 * method does not permit verification of the existence of the
1262 * named directory and all necessary parent directories; or if
1263 * the <code>{@link
1264 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1265 * method does not permit the named directory and all necessary
1266 * parent directories to be created
1267 */
1268 public boolean mkdirs() {
1269 if (exists()) {
1270 return false;
1271 }
1272 if (mkdir()) {
1273 return true;
1274 }
1275 File canonFile = null;
1276 try {
1277 canonFile = getCanonicalFile();
1278 } catch (IOException e) {
1279 return false;
1280 }
1281
1282 File parent = canonFile.getParentFile();
1283 return (parent != null && (parent.mkdirs() || parent.exists()) &&
1284 canonFile.mkdir());
1285 }
1286
1287 /**
1288 * Renames the file denoted by this abstract pathname.
1289 *
1290 * <p> Many aspects of the behavior of this method are inherently
1291 * platform-dependent: The rename operation might not be able to move a
1292 * file from one filesystem to another, it might not be atomic, and it
1293 * might not succeed if a file with the destination abstract pathname
1294 * already exists. The return value should always be checked to make sure
1295 * that the rename operation was successful.
1296 *
1297 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1298 * java.nio.file.Files#move move} method to move or rename a file in a
1299 * platform independent manner.
1300 *
1301 * @param dest The new abstract pathname for the named file
1302 *
1303 * @return <code>true</code> if and only if the renaming succeeded;
1304 * <code>false</code> otherwise
1305 *
1306 * @throws SecurityException
1307 * If a security manager exists and its <code>{@link
1308 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1309 * method denies write access to either the old or new pathnames
1310 *
1311 * @throws NullPointerException
1312 * If parameter <code>dest</code> is <code>null</code>
1313 */
1314 public boolean renameTo(File dest) {
1315 SecurityManager security = System.getSecurityManager();
1316 if (security != null) {
1317 security.checkWrite(path);
1318 security.checkWrite(dest.path);
1319 }
1320 return fs.rename(this, dest);
1321 }
1322
1323 /**
1324 * Sets the last-modified time of the file or directory named by this
1325 * abstract pathname.
1326 *
1327 * <p> All platforms support file-modification times to the nearest second,
1328 * but some provide more precision. The argument will be truncated to fit
1329 * the supported precision. If the operation succeeds and no intervening
1330 * operations on the file take place, then the next invocation of the
1331 * <code>{@link #lastModified}</code> method will return the (possibly
1332 * truncated) <code>time</code> argument that was passed to this method.
1333 *
1334 * @param time The new last-modified time, measured in milliseconds since
1335 * the epoch (00:00:00 GMT, January 1, 1970)
1336 *
1337 * @return <code>true</code> if and only if the operation succeeded;
1338 * <code>false</code> otherwise
1339 *
1340 * @throws IllegalArgumentException If the argument is negative
1341 *
1342 * @throws SecurityException
1343 * If a security manager exists and its <code>{@link
1344 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1345 * method denies write access to the named file
1346 *
1347 * @since 1.2
1348 */
1349 public boolean setLastModified(long time) {
1350 if (time < 0) throw new IllegalArgumentException("Negative time");
1351 SecurityManager security = System.getSecurityManager();
1352 if (security != null) {
1353 security.checkWrite(path);
1354 }
1355 return fs.setLastModifiedTime(this, time);
1356 }
1357
1358 /**
1359 * Marks the file or directory named by this abstract pathname so that
1360 * only read operations are allowed. After invoking this method the file
1361 * or directory will not change until it is either deleted or marked
1362 * to allow write access. On some platforms it may be possible to start the
1363 * Java virtual machine with special privileges that allow it to modify
1364 * files that are marked read-only. Whether or not a read-only file or
1365 * directory may be deleted depends upon the underlying system.
1366 *
1367 * @return <code>true</code> if and only if the operation succeeded;
1368 * <code>false</code> otherwise
1369 *
1370 * @throws SecurityException
1371 * If a security manager exists and its <code>{@link
1372 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1373 * method denies write access to the named file
1374 *
1375 * @since 1.2
1376 */
1377 public boolean setReadOnly() {
1378 SecurityManager security = System.getSecurityManager();
1379 if (security != null) {
1380 security.checkWrite(path);
1381 }
1382 return fs.setReadOnly(this);
1383 }
1384
1385 /**
1386 * Sets the owner's or everybody's write permission for this abstract
1387 * pathname. On some platforms it may be possible to start the Java virtual
1388 * machine with special privileges that allow it to modify files that
1389 * disallow write operations.
1390 *
1391 * <p> The {@link java.nio.file.Files} class defines methods that operate on
1392 * file attributes including file permissions. This may be used when finer
1393 * manipulation of file permissions is required.
1394 *
1395 * @param writable
1396 * If <code>true</code>, sets the access permission to allow write
1397 * operations; if <code>false</code> to disallow write operations
1398 *
1399 * @param ownerOnly
1400 * If <code>true</code>, the write permission applies only to the
1401 * owner's write permission; otherwise, it applies to everybody. If
1402 * the underlying file system can not distinguish the owner's write
1403 * permission from that of others, then the permission will apply to
1404 * everybody, regardless of this value.
1405 *
1406 * @return <code>true</code> if and only if the operation succeeded. The
1407 * operation will fail if the user does not have permission to change
1408 * the access permissions of this abstract pathname.
1409 *
1410 * @throws SecurityException
1411 * If a security manager exists and its <code>{@link
1412 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1413 * method denies write access to the named file
1414 *
1415 * @since 1.6
1416 */
1417 public boolean setWritable(boolean writable, boolean ownerOnly) {
1418 SecurityManager security = System.getSecurityManager();
1419 if (security != null) {
1420 security.checkWrite(path);
1421 }
1422 return fs.setPermission(this, FileSystem.ACCESS_WRITE, writable, ownerOnly);
1423 }
1424
1425 /**
1426 * A convenience method to set the owner's write permission for this abstract
1427 * pathname. On some platforms it may be possible to start the Java virtual
1428 * machine with special privileges that allow it to modify files that
1429 * disallow write operations.
1430 *
1431 * <p> An invocation of this method of the form <tt>file.setWritable(arg)</tt>
1432 * behaves in exactly the same way as the invocation
1433 *
1434 * <pre>
1435 * file.setWritable(arg, true) </pre>
1436 *
1437 * @param writable
1438 * If <code>true</code>, sets the access permission to allow write
1439 * operations; if <code>false</code> to disallow write operations
1440 *
1441 * @return <code>true</code> if and only if the operation succeeded. The
1442 * operation will fail if the user does not have permission to
1443 * change the access permissions of this abstract pathname.
1444 *
1445 * @throws SecurityException
1446 * If a security manager exists and its <code>{@link
1447 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1448 * method denies write access to the file
1449 *
1450 * @since 1.6
1451 */
1452 public boolean setWritable(boolean writable) {
1453 return setWritable(writable, true);
1454 }
1455
1456 /**
1457 * Sets the owner's or everybody's read permission for this abstract
1458 * pathname. On some platforms it may be possible to start the Java virtual
1459 * machine with special privileges that allow it to read files that are
1460 * marked as unreadable.
1461 *
1462 * <p> The {@link java.nio.file.Files} class defines methods that operate on
1463 * file attributes including file permissions. This may be used when finer
1464 * manipulation of file permissions is required.
1465 *
1466 * @param readable
1467 * If <code>true</code>, sets the access permission to allow read
1468 * operations; if <code>false</code> to disallow read operations
1469 *
1470 * @param ownerOnly
1471 * If <code>true</code>, the read permission applies only to the
1472 * owner's read permission; otherwise, it applies to everybody. If
1473 * the underlying file system can not distinguish the owner's read
1474 * permission from that of others, then the permission will apply to
1475 * everybody, regardless of this value.
1476 *
1477 * @return <code>true</code> if and only if the operation succeeded. The
1478 * operation will fail if the user does not have permission to
1479 * change the access permissions of this abstract pathname. If
1480 * <code>readable</code> is <code>false</code> and the underlying
1481 * file system does not implement a read permission, then the
1482 * operation will fail.
1483 *
1484 * @throws SecurityException
1485 * If a security manager exists and its <code>{@link
1486 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1487 * method denies write access to the file
1488 *
1489 * @since 1.6
1490 */
1491 public boolean setReadable(boolean readable, boolean ownerOnly) {
1492 SecurityManager security = System.getSecurityManager();
1493 if (security != null) {
1494 security.checkWrite(path);
1495 }
1496 return fs.setPermission(this, FileSystem.ACCESS_READ, readable, ownerOnly);
1497 }
1498
1499 /**
1500 * A convenience method to set the owner's read permission for this abstract
1501 * pathname. On some platforms it may be possible to start the Java virtual
1502 * machine with special privileges that allow it to read files that that are
1503 * marked as unreadable.
1504 *
1505 * <p>An invocation of this method of the form <tt>file.setReadable(arg)</tt>
1506 * behaves in exactly the same way as the invocation
1507 *
1508 * <pre>
1509 * file.setReadable(arg, true) </pre>
1510 *
1511 * @param readable
1512 * If <code>true</code>, sets the access permission to allow read
1513 * operations; if <code>false</code> to disallow read operations
1514 *
1515 * @return <code>true</code> if and only if the operation succeeded. The
1516 * operation will fail if the user does not have permission to
1517 * change the access permissions of this abstract pathname. If
1518 * <code>readable</code> is <code>false</code> and the underlying
1519 * file system does not implement a read permission, then the
1520 * operation will fail.
1521 *
1522 * @throws SecurityException
1523 * If a security manager exists and its <code>{@link
1524 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1525 * method denies write access to the file
1526 *
1527 * @since 1.6
1528 */
1529 public boolean setReadable(boolean readable) {
1530 return setReadable(readable, true);
1531 }
1532
1533 /**
1534 * Sets the owner's or everybody's execute permission for this abstract
1535 * pathname. On some platforms it may be possible to start the Java virtual
1536 * machine with special privileges that allow it to execute files that are
1537 * not marked executable.
1538 *
1539 * <p> The {@link java.nio.file.Files} class defines methods that operate on
1540 * file attributes including file permissions. This may be used when finer
1541 * manipulation of file permissions is required.
1542 *
1543 * @param executable
1544 * If <code>true</code>, sets the access permission to allow execute
1545 * operations; if <code>false</code> to disallow execute operations
1546 *
1547 * @param ownerOnly
1548 * If <code>true</code>, the execute permission applies only to the
1549 * owner's execute permission; otherwise, it applies to everybody.
1550 * If the underlying file system can not distinguish the owner's
1551 * execute permission from that of others, then the permission will
1552 * apply to everybody, regardless of this value.
1553 *
1554 * @return <code>true</code> if and only if the operation succeeded. The
1555 * operation will fail if the user does not have permission to
1556 * change the access permissions of this abstract pathname. If
1557 * <code>executable</code> is <code>false</code> and the underlying
1558 * file system does not implement an execute permission, then the
1559 * operation will fail.
1560 *
1561 * @throws SecurityException
1562 * If a security manager exists and its <code>{@link
1563 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1564 * method denies write access to the file
1565 *
1566 * @since 1.6
1567 */
1568 public boolean setExecutable(boolean executable, boolean ownerOnly) {
1569 SecurityManager security = System.getSecurityManager();
1570 if (security != null) {
1571 security.checkWrite(path);
1572 }
1573 return fs.setPermission(this, FileSystem.ACCESS_EXECUTE, executable, ownerOnly);
1574 }
1575
1576 /**
1577 * A convenience method to set the owner's execute permission for this
1578 * abstract pathname. On some platforms it may be possible to start the Java
1579 * virtual machine with special privileges that allow it to execute files
1580 * that are not marked executable.
1581 *
1582 * <p>An invocation of this method of the form <tt>file.setExcutable(arg)</tt>
1583 * behaves in exactly the same way as the invocation
1584 *
1585 * <pre>
1586 * file.setExecutable(arg, true) </pre>
1587 *
1588 * @param executable
1589 * If <code>true</code>, sets the access permission to allow execute
1590 * operations; if <code>false</code> to disallow execute operations
1591 *
1592 * @return <code>true</code> if and only if the operation succeeded. The
1593 * operation will fail if the user does not have permission to
1594 * change the access permissions of this abstract pathname. If
1595 * <code>executable</code> is <code>false</code> and the underlying
1596 * file system does not implement an excute permission, then the
1597 * operation will fail.
1598 *
1599 * @throws SecurityException
1600 * If a security manager exists and its <code>{@link
1601 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1602 * method denies write access to the file
1603 *
1604 * @since 1.6
1605 */
1606 public boolean setExecutable(boolean executable) {
1607 return setExecutable(executable, true);
1608 }
1609
1610 /**
1611 * Tests whether the application can execute the file denoted by this
1612 * abstract pathname. On some platforms it may be possible to start the
1613 * Java virtual machine with special privileges that allow it to execute
1614 * files that are not marked executable. Consequently this method may return
1615 * {@code true} even though the file does not have execute permissions.
1616 *
1617 * @return <code>true</code> if and only if the abstract pathname exists
1618 * <em>and</em> the application is allowed to execute the file
1619 *
1620 * @throws SecurityException
1621 * If a security manager exists and its <code>{@link
1622 * java.lang.SecurityManager#checkExec(java.lang.String)}</code>
1623 * method denies execute access to the file
1624 *
1625 * @since 1.6
1626 */
1627 public boolean canExecute() {
1628 SecurityManager security = System.getSecurityManager();
1629 if (security != null) {
1630 security.checkExec(path);
1631 }
1632 return fs.checkAccess(this, FileSystem.ACCESS_EXECUTE);
1633 }
1634
1635
1636 /* -- Filesystem interface -- */
1637
1638 /**
1639 * List the available filesystem roots.
1640 *
1641 * <p> A particular Java platform may support zero or more
1642 * hierarchically-organized file systems. Each file system has a
1643 * {@code root} directory from which all other files in that file system
1644 * can be reached. Windows platforms, for example, have a root directory
1645 * for each active drive; UNIX platforms have a single root directory,
1646 * namely {@code "/"}. The set of available filesystem roots is affected
1647 * by various system-level operations such as the insertion or ejection of
1648 * removable media and the disconnecting or unmounting of physical or
1649 * virtual disk drives.
1650 *
1651 * <p> This method returns an array of {@code File} objects that denote the
1652 * root directories of the available filesystem roots. It is guaranteed
1653 * that the canonical pathname of any file physically present on the local
1654 * machine will begin with one of the roots returned by this method.
1655 *
1656 * <p> The canonical pathname of a file that resides on some other machine
1657 * and is accessed via a remote-filesystem protocol such as SMB or NFS may
1658 * or may not begin with one of the roots returned by this method. If the
1659 * pathname of a remote file is syntactically indistinguishable from the
1660 * pathname of a local file then it will begin with one of the roots
1661 * returned by this method. Thus, for example, {@code File} objects
1662 * denoting the root directories of the mapped network drives of a Windows
1663 * platform will be returned by this method, while {@code File} objects
1664 * containing UNC pathnames will not be returned by this method.
1665 *
1666 * <p> Unlike most methods in this class, this method does not throw
1667 * security exceptions. If a security manager exists and its {@link
1668 * SecurityManager#checkRead(String)} method denies read access to a
1669 * particular root directory, then that directory will not appear in the
1670 * result.
1671 *
1672 * @return An array of {@code File} objects denoting the available
1673 * filesystem roots, or {@code null} if the set of roots could not
1674 * be determined. The array will be empty if there are no
1675 * filesystem roots.
1676 *
1677 * @since 1.2
1678 * @see java.nio.file.FileStore
1679 */
1680 public static File[] listRoots() {
1681 return fs.listRoots();
1682 }
1683
1684
1685 /* -- Disk usage -- */
1686
1687 /**
1688 * Returns the size of the partition <a href="#partName">named</a> by this
1689 * abstract pathname.
1690 *
1691 * @return The size, in bytes, of the partition or <tt>0L</tt> if this
1692 * abstract pathname does not name a partition
1693 *
1694 * @throws SecurityException
1695 * If a security manager has been installed and it denies
1696 * {@link RuntimePermission}<tt>("getFileSystemAttributes")</tt>
1697 * or its {@link SecurityManager#checkRead(String)} method denies
1698 * read access to the file named by this abstract pathname
1699 *
1700 * @since 1.6
1701 */
1702 public long getTotalSpace() {
1703 SecurityManager sm = System.getSecurityManager();
1704 if (sm != null) {
1705 sm.checkPermission(new RuntimePermission("getFileSystemAttributes"));
1706 sm.checkRead(path);
1707 }
1708 return fs.getSpace(this, FileSystem.SPACE_TOTAL);
1709 }
1710
1711 /**
1712 * Returns the number of unallocated bytes in the partition <a
1713 * href="#partName">named</a> by this abstract path name.
1714 *
1715 * <p> The returned number of unallocated bytes is a hint, but not
1716 * a guarantee, that it is possible to use most or any of these
1717 * bytes. The number of unallocated bytes is most likely to be
1718 * accurate immediately after this call. It is likely to be made
1719 * inaccurate by any external I/O operations including those made
1720 * on the system outside of this virtual machine. This method
1721 * makes no guarantee that write operations to this file system
1722 * will succeed.
1723 *
1724 * @return The number of unallocated bytes on the partition <tt>0L</tt>
1725 * if the abstract pathname does not name a partition. This
1726 * value will be less than or equal to the total file system size
1727 * returned by {@link #getTotalSpace}.
1728 *
1729 * @throws SecurityException
1730 * If a security manager has been installed and it denies
1731 * {@link RuntimePermission}<tt>("getFileSystemAttributes")</tt>
1732 * or its {@link SecurityManager#checkRead(String)} method denies
1733 * read access to the file named by this abstract pathname
1734 *
1735 * @since 1.6
1736 */
1737 public long getFreeSpace() {
1738 SecurityManager sm = System.getSecurityManager();
1739 if (sm != null) {
1740 sm.checkPermission(new RuntimePermission("getFileSystemAttributes"));
1741 sm.checkRead(path);
1742 }
1743 return fs.getSpace(this, FileSystem.SPACE_FREE);
1744 }
1745
1746 /**
1747 * Returns the number of bytes available to this virtual machine on the
1748 * partition <a href="#partName">named</a> by this abstract pathname. When
1749 * possible, this method checks for write permissions and other operating
1750 * system restrictions and will therefore usually provide a more accurate
1751 * estimate of how much new data can actually be written than {@link
1752 * #getFreeSpace}.
1753 *
1754 * <p> The returned number of available bytes is a hint, but not a
1755 * guarantee, that it is possible to use most or any of these bytes. The
1756 * number of unallocated bytes is most likely to be accurate immediately
1757 * after this call. It is likely to be made inaccurate by any external
1758 * I/O operations including those made on the system outside of this
1759 * virtual machine. This method makes no guarantee that write operations
1760 * to this file system will succeed.
1761 *
1762 * @return The number of available bytes on the partition or <tt>0L</tt>
1763 * if the abstract pathname does not name a partition. On
1764 * systems where this information is not available, this method
1765 * will be equivalent to a call to {@link #getFreeSpace}.
1766 *
1767 * @throws SecurityException
1768 * If a security manager has been installed and it denies
1769 * {@link RuntimePermission}<tt>("getFileSystemAttributes")</tt>
1770 * or its {@link SecurityManager#checkRead(String)} method denies
1771 * read access to the file named by this abstract pathname
1772 *
1773 * @since 1.6
1774 */
1775 public long getUsableSpace() {
1776 SecurityManager sm = System.getSecurityManager();
1777 if (sm != null) {
1778 sm.checkPermission(new RuntimePermission("getFileSystemAttributes"));
1779 sm.checkRead(path);
1780 }
1781 return fs.getSpace(this, FileSystem.SPACE_USABLE);
1782 }
1783
1784 /* -- Temporary files -- */
1785
1786 private static class TempDirectory {
1787 private TempDirectory() { }
1788
1789 // temporary directory location
1790 private static final File tmpdir = new File(fs.normalize(AccessController
1791 .doPrivileged(new GetPropertyAction("java.io.tmpdir"))));
1792 static File location() {
1793 return tmpdir;
1794 }
1795
1796 // file name generation
1797 private static final SecureRandom random = new SecureRandom();
1798 static File generateFile(String prefix, String suffix, File dir) {
1799 long n = random.nextLong();
1800 if (n == Long.MIN_VALUE) {
1801 n = 0; // corner case
1802 } else {
1803 n = Math.abs(n);
1804 }
1805 return new File(dir, prefix + Long.toString(n) + suffix);
1806 }
1807 }
1808
1809 /**
1810 * <p> Creates a new empty file in the specified directory, using the
1811 * given prefix and suffix strings to generate its name. If this method
1812 * returns successfully then it is guaranteed that:
1813 *
1814 * <ol>
1815 * <li> The file denoted by the returned abstract pathname did not exist
1816 * before this method was invoked, and
1817 * <li> Neither this method nor any of its variants will return the same
1818 * abstract pathname again in the current invocation of the virtual
1819 * machine.
1820 * </ol>
1821 *
1822 * This method provides only part of a temporary-file facility. To arrange
1823 * for a file created by this method to be deleted automatically, use the
1824 * <code>{@link #deleteOnExit}</code> method.
1825 *
1826 * <p> The <code>prefix</code> argument must be at least three characters
1827 * long. It is recommended that the prefix be a short, meaningful string
1828 * such as <code>"hjb"</code> or <code>"mail"</code>. The
1829 * <code>suffix</code> argument may be <code>null</code>, in which case the
1830 * suffix <code>".tmp"</code> will be used.
1831 *
1832 * <p> To create the new file, the prefix and the suffix may first be
1833 * adjusted to fit the limitations of the underlying platform. If the
1834 * prefix is too long then it will be truncated, but its first three
1835 * characters will always be preserved. If the suffix is too long then it
1836 * too will be truncated, but if it begins with a period character
1837 * (<code>'.'</code>) then the period and the first three characters
1838 * following it will always be preserved. Once these adjustments have been
1839 * made the name of the new file will be generated by concatenating the
1840 * prefix, five or more internally-generated characters, and the suffix.
1841 *
1842 * <p> If the <code>directory</code> argument is <code>null</code> then the
1843 * system-dependent default temporary-file directory will be used. The
1844 * default temporary-file directory is specified by the system property
1845 * <code>java.io.tmpdir</code>. On UNIX systems the default value of this
1846 * property is typically <code>"/tmp"</code> or <code>"/var/tmp"</code>; on
1847 * Microsoft Windows systems it is typically <code>"C:\\WINNT\\TEMP"</code>. A different
1848 * value may be given to this system property when the Java virtual machine
1849 * is invoked, but programmatic changes to this property are not guaranteed
1850 * to have any effect upon the temporary directory used by this method.
1851 *
1852 * @param prefix The prefix string to be used in generating the file's
1853 * name; must be at least three characters long
1854 *
1855 * @param suffix The suffix string to be used in generating the file's
1856 * name; may be <code>null</code>, in which case the
1857 * suffix <code>".tmp"</code> will be used
1858 *
1859 * @param directory The directory in which the file is to be created, or
1860 * <code>null</code> if the default temporary-file
1861 * directory is to be used
1862 *
1863 * @return An abstract pathname denoting a newly-created empty file
1864 *
1865 * @throws IllegalArgumentException
1866 * If the <code>prefix</code> argument contains fewer than three
1867 * characters
1868 *
1869 * @throws IOException If a file could not be created
1870 *
1871 * @throws SecurityException
1872 * If a security manager exists and its <code>{@link
1873 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1874 * method does not allow a file to be created
1875 *
1876 * @since 1.2
1877 */
1878 public static File createTempFile(String prefix, String suffix,
1879 File directory)
1880 throws IOException
1881 {
1882 if (prefix.length() < 3)
1883 throw new IllegalArgumentException("Prefix string too short");
1884 if (suffix == null)
1885 suffix = ".tmp";
1886
1887 File tmpdir = (directory != null) ? directory : TempDirectory.location();
1888 SecurityManager sm = System.getSecurityManager();
1889 File f;
1890 do {
1891 f = TempDirectory.generateFile(prefix, suffix, tmpdir);
1892 if (sm != null) {
1893 try {
1894 sm.checkWrite(f.getPath());
1895 } catch (SecurityException se) {
1896 // don't reveal temporary directory location
1897 if (directory == null)
1898 throw new SecurityException("Unable to create temporary file");
1899 throw se;
1900 }
1901 }
1902 } while (!fs.createFileExclusively(f.getPath()));
1903 return f;
1904 }
1905
1906 /**
1907 * Creates an empty file in the default temporary-file directory, using
1908 * the given prefix and suffix to generate its name. Invoking this method
1909 * is equivalent to invoking <code>{@link #createTempFile(java.lang.String,
1910 * java.lang.String, java.io.File)
1911 * createTempFile(prefix, suffix, null)}</code>.
1912 *
1913 * <p> The {@link
1914 * java.nio.file.Files#createTempFile(String,String,java.nio.file.attribute.FileAttribute[])
1915 * Files.createTempFile} method provides an alternative method to create an
1916 * empty file in the temporary-file directory. Files created by that method
1917 * may have more restrictive access permissions to files created by this
1918 * method and so may be more suited to security-sensitive applications.
1919 *
1920 * @param prefix The prefix string to be used in generating the file's
1921 * name; must be at least three characters long
1922 *
1923 * @param suffix The suffix string to be used in generating the file's
1924 * name; may be <code>null</code>, in which case the
1925 * suffix <code>".tmp"</code> will be used
1926 *
1927 * @return An abstract pathname denoting a newly-created empty file
1928 *
1929 * @throws IllegalArgumentException
1930 * If the <code>prefix</code> argument contains fewer than three
1931 * characters
1932 *
1933 * @throws IOException If a file could not be created
1934 *
1935 * @throws SecurityException
1936 * If a security manager exists and its <code>{@link
1937 * java.lang.SecurityManager#checkWrite(java.lang.String)}</code>
1938 * method does not allow a file to be created
1939 *
1940 * @since 1.2
1941 * @see java.nio.file.Files#createTempDirectory(String,FileAttribute[])
1942 */
1943 public static File createTempFile(String prefix, String suffix)
1944 throws IOException
1945 {
1946 return createTempFile(prefix, suffix, null);
1947 }
1948
1949 /* -- Basic infrastructure -- */
1950
1951 /**
1952 * Compares two abstract pathnames lexicographically. The ordering
1953 * defined by this method depends upon the underlying system. On UNIX
1954 * systems, alphabetic case is significant in comparing pathnames; on Microsoft Windows
1955 * systems it is not.
1956 *
1957 * @param pathname The abstract pathname to be compared to this abstract
1958 * pathname
1959 *
1960 * @return Zero if the argument is equal to this abstract pathname, a
1961 * value less than zero if this abstract pathname is
1962 * lexicographically less than the argument, or a value greater
1963 * than zero if this abstract pathname is lexicographically
1964 * greater than the argument
1965 *
1966 * @since 1.2
1967 */
1968 public int compareTo(File pathname) {
1969 return fs.compare(this, pathname);
1970 }
1971
1972 /**
1973 * Tests this abstract pathname for equality with the given object.
1974 * Returns <code>true</code> if and only if the argument is not
1975 * <code>null</code> and is an abstract pathname that denotes the same file
1976 * or directory as this abstract pathname. Whether or not two abstract
1977 * pathnames are equal depends upon the underlying system. On UNIX
1978 * systems, alphabetic case is significant in comparing pathnames; on Microsoft Windows
1979 * systems it is not.
1980 *
1981 * @param obj The object to be compared with this abstract pathname
1982 *
1983 * @return <code>true</code> if and only if the objects are the same;
1984 * <code>false</code> otherwise
1985 */
1986 public boolean equals(Object obj) {
1987 if ((obj != null) && (obj instanceof File)) {
1988 return compareTo((File)obj) == 0;
1989 }
1990 return false;
1991 }
1992
1993 /**
1994 * Computes a hash code for this abstract pathname. Because equality of
1995 * abstract pathnames is inherently system-dependent, so is the computation
1996 * of their hash codes. On UNIX systems, the hash code of an abstract
1997 * pathname is equal to the exclusive <em>or</em> of the hash code
1998 * of its pathname string and the decimal value
1999 * <code>1234321</code>. On Microsoft Windows systems, the hash
2000 * code is equal to the exclusive <em>or</em> of the hash code of
2001 * its pathname string converted to lower case and the decimal
2002 * value <code>1234321</code>. Locale is not taken into account on
2003 * lowercasing the pathname string.
2004 *
2005 * @return A hash code for this abstract pathname
2006 */
2007 public int hashCode() {
2008 return fs.hashCode(this);
2009 }
2010
2011 /**
2012 * Returns the pathname string of this abstract pathname. This is just the
2013 * string returned by the <code>{@link #getPath}</code> method.
2014 *
2015 * @return The string form of this abstract pathname
2016 */
2017 public String toString() {
2018 return getPath();
2019 }
2020
2021 /**
2022 * WriteObject is called to save this filename.
2023 * The separator character is saved also so it can be replaced
2024 * in case the path is reconstituted on a different host type.
2025 * <p>
2026 * @serialData Default fields followed by separator character.
2027 */
2028 private synchronized void writeObject(java.io.ObjectOutputStream s)
2029 throws IOException
2030 {
2031 s.defaultWriteObject();
2032 s.writeChar(separatorChar); // Add the separator character
2033 }
2034
2035 /**
2036 * readObject is called to restore this filename.
2037 * The original separator character is read. If it is different
2038 * than the separator character on this system, then the old separator
2039 * is replaced by the local separator.
2040 */
2041 private synchronized void readObject(java.io.ObjectInputStream s)
2042 throws IOException, ClassNotFoundException
2043 {
2044 ObjectInputStream.GetField fields = s.readFields();
2045 String pathField = (String)fields.get("path", null);
2046 char sep = s.readChar(); // read the previous separator char
2047 if (sep != separatorChar)
2048 pathField = pathField.replace(sep, separatorChar);
2049 String path = fs.normalize(pathField);
2050 UNSAFE.putObject(this, PATH_OFFSET, path);
2051 UNSAFE.putIntVolatile(this, PREFIX_LENGTH_OFFSET, fs.prefixLength(path));
2052 }
2053
2054 private static final long PATH_OFFSET;
2055 private static final long PREFIX_LENGTH_OFFSET;
2056 private static final sun.misc.Unsafe UNSAFE;
2057 static {
2058 try {
2059 sun.misc.Unsafe unsafe = sun.misc.Unsafe.getUnsafe();
2060 PATH_OFFSET = unsafe.objectFieldOffset(
2061 File.class.getDeclaredField("path"));
2062 PREFIX_LENGTH_OFFSET = unsafe.objectFieldOffset(
2063 File.class.getDeclaredField("prefixLength"));
2064 UNSAFE = unsafe;
2065 } catch (ReflectiveOperationException e) {
2066 throw new Error(e);
2067 }
2068 }
2069
2070
2071 /** use serialVersionUID from JDK 1.0.2 for interoperability */
2072 private static final long serialVersionUID = 301077366599181567L;
2073
2074 // -- Integration with java.nio.file --
2075
2076 private volatile transient Path filePath;
2077
2078 /**
2079 * Returns a {@link Path java.nio.file.Path} object constructed from the
2080 * this abstract path. The resulting {@code Path} is associated with the
2081 * {@link java.nio.file.FileSystems#getDefault default-filesystem}.
2082 *
2083 * <p> The first invocation of this method works as if invoking it were
2084 * equivalent to evaluating the expression:
2085 * <blockquote><pre>
2086 * {@link java.nio.file.FileSystems#getDefault FileSystems.getDefault}().{@link
2087 * java.nio.file.FileSystem#getPath getPath}(this.{@link #getPath getPath}());
2088 * </pre></blockquote>
2089 * Subsequent invocations of this method return the same {@code Path}.
2090 *
2091 * <p> If this abstract pathname is the empty abstract pathname then this
2092 * method returns a {@code Path} that may be used to access the current
2093 * user directory.
2094 *
2095 * @return a {@code Path} constructed from this abstract path
2096 *
2097 * @throws java.nio.file.InvalidPathException
2098 * if a {@code Path} object cannot be constructed from the abstract
2099 * path (see {@link java.nio.file.FileSystem#getPath FileSystem.getPath})
2100 *
2101 * @since 1.7
2102 * @see Path#toFile
2103 */
2104 public Path toPath() {
2105 Path result = filePath;
2106 if (result == null) {
2107 synchronized (this) {
2108 result = filePath;
2109 if (result == null) {
2110 result = FileSystems.getDefault().getPath(path);
2111 filePath = result;
2112 }
2113 }
2114 }
2115 return result;
2116 }
2117 }