1 /*
2 * Copyright (c) 1994, 2019, 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.nio.file.FileStore;
33 import java.nio.file.FileSystems;
34 import java.nio.file.Path;
35 import java.security.SecureRandom;
36 import java.util.ArrayList;
37 import java.util.List;
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 "/"} for the UNIX root
51 * directory, or {@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}, and
66 * is made available in the public static fields {@link
67 * #separator} and {@link #separatorChar} 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} package always resolve relative pathnames against the
78 * current user directory. This directory is named by the system property
79 * {@code user.dir}, 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 {@code File}
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 {@code "/usr"} is an ancestor of the directory denoted by the
89 * pathname {@code "/usr/local/bin"}.
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 "/"}. Relative pathnames have no prefix. The abstract pathname
99 * denoting the root directory has the prefix {@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 ":"} and
104 * possibly followed by {@code "\\"} if the pathname is absolute. The
105 * prefix of a UNC pathname is {@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 id="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} class are immutable; that is, once
129 * created, the abstract pathname represented by a {@code File} object
130 * will never change.
131 *
132 * <h2>Interoperability with {@code java.nio.file} package</h2>
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 1.0
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 = DefaultFileSystem.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 * Enum type that indicates the status of a file path.
169 */
170 private static enum PathStatus { INVALID, CHECKED };
171
172 /**
173 * The flag indicating whether the file path is invalid.
174 */
175 private transient PathStatus status = null;
176
177 /**
178 * Check if the file has an invalid path. Currently, the inspection of
179 * a file path is very limited, and it only covers Nul character check.
180 * Returning true means the path is definitely invalid/garbage. But
181 * returning false does not guarantee that the path is valid.
182 *
183 * @return true if the file path is invalid.
184 */
185 final boolean isInvalid() {
186 PathStatus s = status;
187 if (s == null) {
188 s = (this.path.indexOf('\u0000') < 0) ? PathStatus.CHECKED
189 : PathStatus.INVALID;
190 status = s;
191 }
192 return s == PathStatus.INVALID;
193 }
194
195 /**
196 * The length of this abstract pathname's prefix, or zero if it has no
197 * prefix.
198 */
199 private final transient int prefixLength;
200
201 /**
202 * Returns the length of this abstract pathname's prefix.
203 * For use by FileSystem classes.
204 */
205 int getPrefixLength() {
206 return prefixLength;
207 }
208
209 /**
210 * The system-dependent default name-separator character. This field is
211 * initialized to contain the first character of the value of the system
212 * property {@code file.separator}. On UNIX systems the value of this
213 * field is {@code '/'}; on Microsoft Windows systems it is {@code '\\'}.
214 *
215 * @see java.lang.System#getProperty(java.lang.String)
216 */
217 public static final char separatorChar = fs.getSeparator();
218
219 /**
220 * The system-dependent default name-separator character, represented as a
221 * string for convenience. This string contains a single character, namely
222 * {@link #separatorChar}.
223 */
224 public static final String separator = "" + separatorChar;
225
226 /**
227 * The system-dependent path-separator character. This field is
228 * initialized to contain the first character of the value of the system
229 * property {@code path.separator}. This character is used to
230 * separate filenames in a sequence of files given as a <em>path list</em>.
231 * On UNIX systems, this character is {@code ':'}; on Microsoft Windows systems it
232 * is {@code ';'}.
233 *
234 * @see java.lang.System#getProperty(java.lang.String)
235 */
236 public static final char pathSeparatorChar = fs.getPathSeparator();
237
238 /**
239 * The system-dependent path-separator character, represented as a string
240 * for convenience. This string contains a single character, namely
241 * {@link #pathSeparatorChar}.
242 */
243 public static final String pathSeparator = "" + pathSeparatorChar;
244
245
246 /* -- Constructors -- */
247
248 /**
249 * Internal constructor for already-normalized pathname strings.
250 */
251 private File(String pathname, int prefixLength) {
252 this.path = pathname;
253 this.prefixLength = prefixLength;
254 }
255
256 /**
257 * Internal constructor for already-normalized pathname strings.
258 * The parameter order is used to disambiguate this method from the
259 * public(File, String) constructor.
260 */
261 private File(String child, File parent) {
262 assert parent.path != null;
263 assert (!parent.path.isEmpty());
264 this.path = fs.resolve(parent.path, child);
265 this.prefixLength = parent.prefixLength;
266 }
267
268 /**
269 * Creates a new {@code File} instance by converting the given
270 * pathname string into an abstract pathname. If the given string is
271 * the empty string, then the result is the empty abstract pathname.
272 *
273 * @param pathname A pathname string
274 * @throws NullPointerException
275 * If the {@code pathname} argument is {@code null}
276 */
277 public File(String pathname) {
278 if (pathname == null) {
279 throw new NullPointerException();
280 }
281 this.path = fs.normalize(pathname);
282 this.prefixLength = fs.prefixLength(this.path);
283 }
284
285 /* Note: The two-argument File constructors do not interpret an empty
286 parent abstract pathname as the current user directory. An empty parent
287 instead causes the child to be resolved against the system-dependent
288 directory defined by the FileSystem.getDefaultParent method. On Unix
289 this default is "/", while on Microsoft Windows it is "\\". This is required for
290 compatibility with the original behavior of this class. */
291
292 /**
293 * Creates a new {@code File} instance from a parent pathname string
294 * and a child pathname string.
295 *
296 * <p> If {@code parent} is {@code null} then the new
297 * {@code File} instance is created as if by invoking the
298 * single-argument {@code File} constructor on the given
299 * {@code child} pathname string.
300 *
301 * <p> Otherwise the {@code parent} pathname string is taken to denote
302 * a directory, and the {@code child} pathname string is taken to
303 * denote either a directory or a file. If the {@code child} pathname
304 * string is absolute then it is converted into a relative pathname in a
305 * system-dependent way. If {@code parent} is the empty string then
306 * the new {@code File} instance is created by converting
307 * {@code child} into an abstract pathname and resolving the result
308 * against a system-dependent default directory. Otherwise each pathname
309 * string is converted into an abstract pathname and the child abstract
310 * pathname is resolved against the parent.
311 *
312 * @param parent The parent pathname string
313 * @param child The child pathname string
314 * @throws NullPointerException
315 * If {@code child} is {@code null}
316 */
317 public File(String parent, String child) {
318 if (child == null) {
319 throw new NullPointerException();
320 }
321 if (parent != null) {
322 if (parent.isEmpty()) {
323 this.path = fs.resolve(fs.getDefaultParent(),
324 fs.normalize(child));
325 } else {
326 this.path = fs.resolve(fs.normalize(parent),
327 fs.normalize(child));
328 }
329 } else {
330 this.path = fs.normalize(child);
331 }
332 this.prefixLength = fs.prefixLength(this.path);
333 }
334
335 /**
336 * Creates a new {@code File} instance from a parent abstract
337 * pathname and a child pathname string.
338 *
339 * <p> If {@code parent} is {@code null} then the new
340 * {@code File} instance is created as if by invoking the
341 * single-argument {@code File} constructor on the given
342 * {@code child} pathname string.
343 *
344 * <p> Otherwise the {@code parent} abstract pathname is taken to
345 * denote a directory, and the {@code child} pathname string is taken
346 * to denote either a directory or a file. If the {@code child}
347 * pathname string is absolute then it is converted into a relative
348 * pathname in a system-dependent way. If {@code parent} is the empty
349 * abstract pathname then the new {@code File} instance is created by
350 * converting {@code child} into an abstract pathname and resolving
351 * the result against a system-dependent default directory. Otherwise each
352 * pathname string is converted into an abstract pathname and the child
353 * abstract pathname is resolved against the parent.
354 *
355 * @param parent The parent abstract pathname
356 * @param child The child pathname string
357 * @throws NullPointerException
358 * If {@code child} is {@code null}
359 */
360 public File(File parent, String child) {
361 if (child == null) {
362 throw new NullPointerException();
363 }
364 if (parent != null) {
365 if (parent.path.isEmpty()) {
366 this.path = fs.resolve(fs.getDefaultParent(),
367 fs.normalize(child));
368 } else {
369 this.path = fs.resolve(parent.path,
370 fs.normalize(child));
371 }
372 } else {
373 this.path = fs.normalize(child);
374 }
375 this.prefixLength = fs.prefixLength(this.path);
376 }
377
378 /**
379 * Creates a new {@code File} instance by converting the given
380 * {@code file:} URI into an abstract pathname.
381 *
382 * <p> The exact form of a {@code file:} URI is system-dependent, hence
383 * the transformation performed by this constructor is also
384 * system-dependent.
385 *
386 * <p> For a given abstract pathname <i>f</i> it is guaranteed that
387 *
388 * <blockquote><code>
389 * new File(</code><i> f</i><code>.{@link #toURI()
390 * toURI}()).equals(</code><i> f</i><code>.{@link #getAbsoluteFile() getAbsoluteFile}())
391 * </code></blockquote>
392 *
393 * so long as the original abstract pathname, the URI, and the new abstract
394 * pathname are all created in (possibly different invocations of) the same
395 * Java virtual machine. This relationship typically does not hold,
396 * however, when a {@code file:} URI that is created in a virtual machine
397 * on one operating system is converted into an abstract pathname in a
398 * virtual machine on a different operating system.
399 *
400 * @param uri
401 * An absolute, hierarchical URI with a scheme equal to
402 * {@code "file"}, a non-empty path component, and undefined
403 * authority, query, and fragment components
404 *
405 * @throws NullPointerException
406 * If {@code uri} is {@code null}
407 *
408 * @throws IllegalArgumentException
409 * If the preconditions on the parameter do not hold
410 *
411 * @see #toURI()
412 * @see java.net.URI
413 * @since 1.4
414 */
415 public File(URI uri) {
416
417 // Check our many preconditions
418 if (!uri.isAbsolute())
419 throw new IllegalArgumentException("URI is not absolute");
420 if (uri.isOpaque())
421 throw new IllegalArgumentException("URI is not hierarchical");
422 String scheme = uri.getScheme();
423 if ((scheme == null) || !scheme.equalsIgnoreCase("file"))
424 throw new IllegalArgumentException("URI scheme is not \"file\"");
425 if (uri.getRawAuthority() != null)
426 throw new IllegalArgumentException("URI has an authority component");
427 if (uri.getRawFragment() != null)
428 throw new IllegalArgumentException("URI has a fragment component");
429 if (uri.getRawQuery() != null)
430 throw new IllegalArgumentException("URI has a query component");
431 String p = uri.getPath();
432 if (p.isEmpty())
433 throw new IllegalArgumentException("URI path component is empty");
434
435 // Okay, now initialize
436 p = fs.fromURIPath(p);
437 if (File.separatorChar != '/')
438 p = p.replace('/', File.separatorChar);
439 this.path = fs.normalize(p);
440 this.prefixLength = fs.prefixLength(this.path);
441 }
442
443
444 /* -- Path-component accessors -- */
445
446 /**
447 * Returns the name of the file or directory denoted by this abstract
448 * pathname. This is just the last name in the pathname's name
449 * sequence. If the pathname's name sequence is empty, then the empty
450 * string is returned.
451 *
452 * @return The name of the file or directory denoted by this abstract
453 * pathname, or the empty string if this pathname's name sequence
454 * is empty
455 */
456 public String getName() {
457 int index = path.lastIndexOf(separatorChar);
458 if (index < prefixLength) return path.substring(prefixLength);
459 return path.substring(index + 1);
460 }
461
462 /**
463 * Returns the pathname string of this abstract pathname's parent, or
464 * {@code null} if this pathname does not name a parent directory.
465 *
466 * <p> The <em>parent</em> of an abstract pathname consists of the
467 * pathname's prefix, if any, and each name in the pathname's name
468 * sequence except for the last. If the name sequence is empty then
469 * the pathname does not name a parent directory.
470 *
471 * @return The pathname string of the parent directory named by this
472 * abstract pathname, or {@code null} if this pathname
473 * does not name a parent
474 */
475 public String getParent() {
476 int index = path.lastIndexOf(separatorChar);
477 if (index < prefixLength) {
478 if ((prefixLength > 0) && (path.length() > prefixLength))
479 return path.substring(0, prefixLength);
480 return null;
481 }
482 return path.substring(0, index);
483 }
484
485 /**
486 * Returns the abstract pathname of this abstract pathname's parent,
487 * or {@code null} if this pathname does not name a parent
488 * directory.
489 *
490 * <p> The <em>parent</em> of an abstract pathname consists of the
491 * pathname's prefix, if any, and each name in the pathname's name
492 * sequence except for the last. If the name sequence is empty then
493 * the pathname does not name a parent directory.
494 *
495 * @return The abstract pathname of the parent directory named by this
496 * abstract pathname, or {@code null} if this pathname
497 * does not name a parent
498 *
499 * @since 1.2
500 */
501 public File getParentFile() {
502 String p = this.getParent();
503 if (p == null) return null;
504 return new File(p, this.prefixLength);
505 }
506
507 /**
508 * Converts this abstract pathname into a pathname string. The resulting
509 * string uses the {@link #separator default name-separator character} to
510 * separate the names in the name sequence.
511 *
512 * @return The string form of this abstract pathname
513 */
514 public String getPath() {
515 return path;
516 }
517
518
519 /* -- Path operations -- */
520
521 /**
522 * Tests whether this abstract pathname is absolute. The definition of
523 * absolute pathname is system dependent. On UNIX systems, a pathname is
524 * absolute if its prefix is {@code "/"}. On Microsoft Windows systems, a
525 * pathname is absolute if its prefix is a drive specifier followed by
526 * {@code "\\"}, or if its prefix is {@code "\\\\"}.
527 *
528 * @return {@code true} if this abstract pathname is absolute,
529 * {@code false} otherwise
530 */
531 public boolean isAbsolute() {
532 return fs.isAbsolute(this);
533 }
534
535 /**
536 * Returns the absolute pathname string of this abstract pathname.
537 *
538 * <p> If this abstract pathname is already absolute, then the pathname
539 * string is simply returned as if by the {@link #getPath}
540 * method. If this abstract pathname is the empty abstract pathname then
541 * the pathname string of the current user directory, which is named by the
542 * system property {@code user.dir}, is returned. Otherwise this
543 * pathname is resolved in a system-dependent way. On UNIX systems, a
544 * relative pathname is made absolute by resolving it against the current
545 * user directory. On Microsoft Windows systems, a relative pathname is made absolute
546 * by resolving it against the current directory of the drive named by the
547 * pathname, if any; if not, it is resolved against the current user
548 * directory.
549 *
550 * @return The absolute pathname string denoting the same file or
551 * directory as this abstract pathname
552 *
553 * @throws SecurityException
554 * If a required system property value cannot be accessed.
555 *
556 * @see java.io.File#isAbsolute()
557 */
558 public String getAbsolutePath() {
559 return fs.resolve(this);
560 }
561
562 /**
563 * Returns the absolute form of this abstract pathname. Equivalent to
564 * <code>new File(this.{@link #getAbsolutePath})</code>.
565 *
566 * @return The absolute abstract pathname denoting the same file or
567 * directory as this abstract pathname
568 *
569 * @throws SecurityException
570 * If a required system property value cannot be accessed.
571 *
572 * @since 1.2
573 */
574 public File getAbsoluteFile() {
575 String absPath = getAbsolutePath();
576 return new File(absPath, fs.prefixLength(absPath));
577 }
578
579 /**
580 * Returns the canonical pathname string of this abstract pathname.
581 *
582 * <p> A canonical pathname is both absolute and unique. The precise
583 * definition of canonical form is system-dependent. This method first
584 * converts this pathname to absolute form if necessary, as if by invoking the
585 * {@link #getAbsolutePath} method, and then maps it to its unique form in a
586 * system-dependent way. This typically involves removing redundant names
587 * such as {@code "."} and {@code ".."} from the pathname, resolving
588 * symbolic links (on UNIX platforms), and converting drive letters to a
589 * standard case (on Microsoft Windows platforms).
590 *
591 * <p> Every pathname that denotes an existing file or directory has a
592 * unique canonical form. Every pathname that denotes a nonexistent file
593 * or directory also has a unique canonical form. The canonical form of
594 * the pathname of a nonexistent file or directory may be different from
595 * the canonical form of the same pathname after the file or directory is
596 * created. Similarly, the canonical form of the pathname of an existing
597 * file or directory may be different from the canonical form of the same
598 * pathname after the file or directory is deleted.
599 *
600 * @return The canonical pathname string denoting the same file or
601 * directory as this abstract pathname
602 *
603 * @throws IOException
604 * If an I/O error occurs, which is possible because the
605 * construction of the canonical pathname may require
606 * filesystem queries
607 *
608 * @throws SecurityException
609 * If a required system property value cannot be accessed, or
610 * if a security manager exists and its {@link
611 * java.lang.SecurityManager#checkRead} method denies
612 * read access to the file
613 *
614 * @since 1.1
615 * @see Path#toRealPath
616 */
617 public String getCanonicalPath() throws IOException {
618 if (isInvalid()) {
619 throw new IOException("Invalid file path");
620 }
621 return fs.canonicalize(fs.resolve(this));
622 }
623
624 /**
625 * Returns the canonical form of this abstract pathname. Equivalent to
626 * <code>new File(this.{@link #getCanonicalPath})</code>.
627 *
628 * @return The canonical pathname string denoting the same file or
629 * directory as this abstract pathname
630 *
631 * @throws IOException
632 * If an I/O error occurs, which is possible because the
633 * construction of the canonical pathname may require
634 * filesystem queries
635 *
636 * @throws SecurityException
637 * If a required system property value cannot be accessed, or
638 * if a security manager exists and its {@link
639 * java.lang.SecurityManager#checkRead} method denies
640 * read access to the file
641 *
642 * @since 1.2
643 * @see Path#toRealPath
644 */
645 public File getCanonicalFile() throws IOException {
646 String canonPath = getCanonicalPath();
647 return new File(canonPath, fs.prefixLength(canonPath));
648 }
649
650 private static String slashify(String path, boolean isDirectory) {
651 String p = path;
652 if (File.separatorChar != '/')
653 p = p.replace(File.separatorChar, '/');
654 if (!p.startsWith("/"))
655 p = "/" + p;
656 if (!p.endsWith("/") && isDirectory)
657 p = p + "/";
658 return p;
659 }
660
661 /**
662 * Converts this abstract pathname into a {@code file:} URL. The
663 * exact form of the URL is system-dependent. If it can be determined that
664 * the file denoted by this abstract pathname is a directory, then the
665 * resulting URL will end with a slash.
666 *
667 * @return A URL object representing the equivalent file URL
668 *
669 * @throws MalformedURLException
670 * If the path cannot be parsed as a URL
671 *
672 * @see #toURI()
673 * @see java.net.URI
674 * @see java.net.URI#toURL()
675 * @see java.net.URL
676 * @since 1.2
677 *
678 * @deprecated This method does not automatically escape characters that
679 * are illegal in URLs. It is recommended that new code convert an
680 * abstract pathname into a URL by first converting it into a URI, via the
681 * {@link #toURI() toURI} method, and then converting the URI into a URL
682 * via the {@link java.net.URI#toURL() URI.toURL} method.
683 */
684 @Deprecated
685 public URL toURL() throws MalformedURLException {
686 if (isInvalid()) {
687 throw new MalformedURLException("Invalid file path");
688 }
689 return new URL("file", "", slashify(getAbsolutePath(), isDirectory()));
690 }
691
692 /**
693 * Constructs a {@code file:} URI that represents this abstract pathname.
694 *
695 * <p> The exact form of the URI is system-dependent. If it can be
696 * determined that the file denoted by this abstract pathname is a
697 * directory, then the resulting URI will end with a slash.
698 *
699 * <p> For a given abstract pathname <i>f</i>, it is guaranteed that
700 *
701 * <blockquote><code>
702 * new {@link #File(java.net.URI) File}(</code><i> f</i><code>.toURI()).equals(
703 * </code><i> f</i><code>.{@link #getAbsoluteFile() getAbsoluteFile}())
704 * </code></blockquote>
705 *
706 * so long as the original abstract pathname, the URI, and the new abstract
707 * pathname are all created in (possibly different invocations of) the same
708 * Java virtual machine. Due to the system-dependent nature of abstract
709 * pathnames, however, this relationship typically does not hold when a
710 * {@code file:} URI that is created in a virtual machine on one operating
711 * system is converted into an abstract pathname in a virtual machine on a
712 * different operating system.
713 *
714 * <p> Note that when this abstract pathname represents a UNC pathname then
715 * all components of the UNC (including the server name component) are encoded
716 * in the {@code URI} path. The authority component is undefined, meaning
717 * that it is represented as {@code null}. The {@link Path} class defines the
718 * {@link Path#toUri toUri} method to encode the server name in the authority
719 * component of the resulting {@code URI}. The {@link #toPath toPath} method
720 * may be used to obtain a {@code Path} representing this abstract pathname.
721 *
722 * @return An absolute, hierarchical URI with a scheme equal to
723 * {@code "file"}, a path representing this abstract pathname,
724 * and undefined authority, query, and fragment components
725 * @throws SecurityException If a required system property value cannot
726 * be accessed.
727 *
728 * @see #File(java.net.URI)
729 * @see java.net.URI
730 * @see java.net.URI#toURL()
731 * @since 1.4
732 */
733 public URI toURI() {
734 try {
735 File f = getAbsoluteFile();
736 String sp = slashify(f.getPath(), f.isDirectory());
737 if (sp.startsWith("//"))
738 sp = "//" + sp;
739 return new URI("file", null, sp, null);
740 } catch (URISyntaxException x) {
741 throw new Error(x); // Can't happen
742 }
743 }
744
745
746 /* -- Attribute accessors -- */
747
748 /**
749 * Tests whether the application can read the file denoted by this
750 * abstract pathname. On some platforms it may be possible to start the
751 * Java virtual machine with special privileges that allow it to read
752 * files that are marked as unreadable. Consequently this method may return
753 * {@code true} even though the file does not have read permissions.
754 *
755 * @return {@code true} if and only if the file specified by this
756 * abstract pathname exists <em>and</em> can be read by the
757 * application; {@code false} otherwise
758 *
759 * @throws SecurityException
760 * If a security manager exists and its {@link
761 * java.lang.SecurityManager#checkRead(java.lang.String)}
762 * method denies read access to the file
763 */
764 public boolean canRead() {
765 SecurityManager security = System.getSecurityManager();
766 if (security != null) {
767 security.checkRead(path);
768 }
769 if (isInvalid()) {
770 return false;
771 }
772 return fs.checkAccess(this, FileSystem.ACCESS_READ);
773 }
774
775 /**
776 * Tests whether the application can modify the file denoted by this
777 * abstract pathname. On some platforms it may be possible to start the
778 * Java virtual machine with special privileges that allow it to modify
779 * files that are marked read-only. Consequently this method may return
780 * {@code true} even though the file is marked read-only.
781 *
782 * @return {@code true} if and only if the file system actually
783 * contains a file denoted by this abstract pathname <em>and</em>
784 * the application is allowed to write to the file;
785 * {@code false} otherwise.
786 *
787 * @throws SecurityException
788 * If a security manager exists and its {@link
789 * java.lang.SecurityManager#checkWrite(java.lang.String)}
790 * method denies write access to the file
791 */
792 public boolean canWrite() {
793 SecurityManager security = System.getSecurityManager();
794 if (security != null) {
795 security.checkWrite(path);
796 }
797 if (isInvalid()) {
798 return false;
799 }
800 return fs.checkAccess(this, FileSystem.ACCESS_WRITE);
801 }
802
803 /**
804 * Tests whether the file or directory denoted by this abstract pathname
805 * exists.
806 *
807 * @return {@code true} if and only if the file or directory denoted
808 * by this abstract pathname exists; {@code false} otherwise
809 *
810 * @throws SecurityException
811 * If a security manager exists and its {@link
812 * java.lang.SecurityManager#checkRead(java.lang.String)}
813 * method denies read access to the file or directory
814 */
815 public boolean exists() {
816 SecurityManager security = System.getSecurityManager();
817 if (security != null) {
818 security.checkRead(path);
819 }
820 if (isInvalid()) {
821 return false;
822 }
823 return ((fs.getBooleanAttributes(this) & FileSystem.BA_EXISTS) != 0);
824 }
825
826 /**
827 * Tests whether the file denoted by this abstract pathname is a
828 * directory.
829 *
830 * <p> Where it is required to distinguish an I/O exception from the case
831 * that the file is not a directory, or where several attributes of the
832 * same file are required at the same time, then the {@link
833 * java.nio.file.Files#readAttributes(Path,Class,LinkOption[])
834 * Files.readAttributes} method may be used.
835 *
836 * @return {@code true} if and only if the file denoted by this
837 * abstract pathname exists <em>and</em> is a directory;
838 * {@code false} otherwise
839 *
840 * @throws SecurityException
841 * If a security manager exists and its {@link
842 * java.lang.SecurityManager#checkRead(java.lang.String)}
843 * method denies read access to the file
844 */
845 public boolean isDirectory() {
846 SecurityManager security = System.getSecurityManager();
847 if (security != null) {
848 security.checkRead(path);
849 }
850 if (isInvalid()) {
851 return false;
852 }
853 return ((fs.getBooleanAttributes(this) & FileSystem.BA_DIRECTORY)
854 != 0);
855 }
856
857 /**
858 * Tests whether the file denoted by this abstract pathname is a normal
859 * file. A file is <em>normal</em> if it is not a directory and, in
860 * addition, satisfies other system-dependent criteria. Any non-directory
861 * file created by a Java application is guaranteed to be a normal file.
862 *
863 * <p> Where it is required to distinguish an I/O exception from the case
864 * that the file is not a normal file, or where several attributes of the
865 * same file are required at the same time, then the {@link
866 * java.nio.file.Files#readAttributes(Path,Class,LinkOption[])
867 * Files.readAttributes} method may be used.
868 *
869 * @return {@code true} if and only if the file denoted by this
870 * abstract pathname exists <em>and</em> is a normal file;
871 * {@code false} otherwise
872 *
873 * @throws SecurityException
874 * If a security manager exists and its {@link
875 * java.lang.SecurityManager#checkRead(java.lang.String)}
876 * method denies read access to the file
877 */
878 public boolean isFile() {
879 SecurityManager security = System.getSecurityManager();
880 if (security != null) {
881 security.checkRead(path);
882 }
883 if (isInvalid()) {
884 return false;
885 }
886 return ((fs.getBooleanAttributes(this) & FileSystem.BA_REGULAR) != 0);
887 }
888
889 /**
890 * Tests whether the file named by this abstract pathname is a hidden
891 * file. The exact definition of <em>hidden</em> is system-dependent. On
892 * UNIX systems, a file is considered to be hidden if its name begins with
893 * a period character ({@code '.'}). On Microsoft Windows systems, a file is
894 * considered to be hidden if it has been marked as such in the filesystem.
895 *
896 * @return {@code true} if and only if the file denoted by this
897 * abstract pathname is hidden according to the conventions of the
898 * underlying platform
899 *
900 * @throws SecurityException
901 * If a security manager exists and its {@link
902 * java.lang.SecurityManager#checkRead(java.lang.String)}
903 * method denies read access to the file
904 *
905 * @since 1.2
906 */
907 public boolean isHidden() {
908 SecurityManager security = System.getSecurityManager();
909 if (security != null) {
910 security.checkRead(path);
911 }
912 if (isInvalid()) {
913 return false;
914 }
915 return ((fs.getBooleanAttributes(this) & FileSystem.BA_HIDDEN) != 0);
916 }
917
918 /**
919 * Returns the time that the file denoted by this abstract pathname was
920 * last modified.
921 *
922 * @apiNote
923 * While the unit of time of the return value is milliseconds, the
924 * granularity of the value depends on the underlying file system and may
925 * be larger. For example, some file systems use time stamps in units of
926 * seconds.
927 *
928 * <p> Where it is required to distinguish an I/O exception from the case
929 * where {@code 0L} is returned, or where several attributes of the
930 * same file are required at the same time, or where the time of last
931 * access or the creation time are required, then the {@link
932 * java.nio.file.Files#readAttributes(Path,Class,LinkOption[])
933 * Files.readAttributes} method may be used. If however only the
934 * time of last modification is required, then the
935 * {@link java.nio.file.Files#getLastModifiedTime(Path,LinkOption[])
936 * Files.getLastModifiedTime} method may be used instead.
937 *
938 * @return A {@code long} value representing the time the file was
939 * last modified, measured in milliseconds since the epoch
940 * (00:00:00 GMT, January 1, 1970), or {@code 0L} if the
941 * file does not exist or if an I/O error occurs. The value may
942 * be negative indicating the number of milliseconds before the
943 * epoch
944 *
945 * @throws SecurityException
946 * If a security manager exists and its {@link
947 * java.lang.SecurityManager#checkRead(java.lang.String)}
948 * method denies read access to the file
949 */
950 public long lastModified() {
951 SecurityManager security = System.getSecurityManager();
952 if (security != null) {
953 security.checkRead(path);
954 }
955 if (isInvalid()) {
956 return 0L;
957 }
958 return fs.getLastModifiedTime(this);
959 }
960
961 /**
962 * Returns the length of the file denoted by this abstract pathname.
963 * The return value is unspecified if this pathname denotes a directory.
964 *
965 * <p> Where it is required to distinguish an I/O exception from the case
966 * that {@code 0L} is returned, or where several attributes of the same file
967 * are required at the same time, then the {@link
968 * java.nio.file.Files#readAttributes(Path,Class,LinkOption[])
969 * Files.readAttributes} method may be used.
970 *
971 * @return The length, in bytes, of the file denoted by this abstract
972 * pathname, or {@code 0L} if the file does not exist. Some
973 * operating systems may return {@code 0L} for pathnames
974 * denoting system-dependent entities such as devices or pipes.
975 *
976 * @throws SecurityException
977 * If a security manager exists and its {@link
978 * java.lang.SecurityManager#checkRead(java.lang.String)}
979 * method denies read access to the file
980 */
981 public long length() {
982 SecurityManager security = System.getSecurityManager();
983 if (security != null) {
984 security.checkRead(path);
985 }
986 if (isInvalid()) {
987 return 0L;
988 }
989 return fs.getLength(this);
990 }
991
992
993 /* -- File operations -- */
994
995 /**
996 * Atomically creates a new, empty file named by this abstract pathname if
997 * and only if a file with this name does not yet exist. The check for the
998 * existence of the file and the creation of the file if it does not exist
999 * are a single operation that is atomic with respect to all other
1000 * filesystem activities that might affect the file.
1001 * <P>
1002 * Note: this method should <i>not</i> be used for file-locking, as
1003 * the resulting protocol cannot be made to work reliably. The
1004 * {@link java.nio.channels.FileLock FileLock}
1005 * facility should be used instead.
1006 *
1007 * @return {@code true} if the named file does not exist and was
1008 * successfully created; {@code false} if the named file
1009 * already exists
1010 *
1011 * @throws IOException
1012 * If an I/O error occurred
1013 *
1014 * @throws SecurityException
1015 * If a security manager exists and its {@link
1016 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1017 * method denies write access to the file
1018 *
1019 * @since 1.2
1020 */
1021 public boolean createNewFile() throws IOException {
1022 SecurityManager security = System.getSecurityManager();
1023 if (security != null) security.checkWrite(path);
1024 if (isInvalid()) {
1025 throw new IOException("Invalid file path");
1026 }
1027 return fs.createFileExclusively(path);
1028 }
1029
1030 /**
1031 * Deletes the file or directory denoted by this abstract pathname. If
1032 * this pathname denotes a directory, then the directory must be empty in
1033 * order to be deleted.
1034 *
1035 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1036 * java.nio.file.Files#delete(Path) delete} method to throw an {@link IOException}
1037 * when a file cannot be deleted. This is useful for error reporting and to
1038 * diagnose why a file cannot be deleted.
1039 *
1040 * @return {@code true} if and only if the file or directory is
1041 * successfully deleted; {@code false} otherwise
1042 *
1043 * @throws SecurityException
1044 * If a security manager exists and its {@link
1045 * java.lang.SecurityManager#checkDelete} method denies
1046 * delete access to the file
1047 */
1048 public boolean delete() {
1049 SecurityManager security = System.getSecurityManager();
1050 if (security != null) {
1051 security.checkDelete(path);
1052 }
1053 if (isInvalid()) {
1054 return false;
1055 }
1056 return fs.delete(this);
1057 }
1058
1059 /**
1060 * Requests that the file or directory denoted by this abstract
1061 * pathname be deleted when the virtual machine terminates.
1062 * Files (or directories) are deleted in the reverse order that
1063 * they are registered. Invoking this method to delete a file or
1064 * directory that is already registered for deletion has no effect.
1065 * Deletion will be attempted only for normal termination of the
1066 * virtual machine, as defined by the Java Language Specification.
1067 *
1068 * <p> Once deletion has been requested, it is not possible to cancel the
1069 * request. This method should therefore be used with care.
1070 *
1071 * <P>
1072 * Note: this method should <i>not</i> be used for file-locking, as
1073 * the resulting protocol cannot be made to work reliably. The
1074 * {@link java.nio.channels.FileLock FileLock}
1075 * facility should be used instead.
1076 *
1077 * @throws SecurityException
1078 * If a security manager exists and its {@link
1079 * java.lang.SecurityManager#checkDelete} method denies
1080 * delete access to the file
1081 *
1082 * @see #delete
1083 *
1084 * @since 1.2
1085 */
1086 public void deleteOnExit() {
1087 SecurityManager security = System.getSecurityManager();
1088 if (security != null) {
1089 security.checkDelete(path);
1090 }
1091 if (isInvalid()) {
1092 return;
1093 }
1094 DeleteOnExitHook.add(path);
1095 }
1096
1097 /**
1098 * Returns an array of strings naming the files and directories in the
1099 * directory denoted by this abstract pathname.
1100 *
1101 * <p> If this abstract pathname does not denote a directory, then this
1102 * method returns {@code null}. Otherwise an array of strings is
1103 * returned, one for each file or directory in the directory. Names
1104 * denoting the directory itself and the directory's parent directory are
1105 * not included in the result. Each string is a file name rather than a
1106 * complete path.
1107 *
1108 * <p> There is no guarantee that the name strings in the resulting array
1109 * will appear in any specific order; they are not, in particular,
1110 * guaranteed to appear in alphabetical order.
1111 *
1112 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1113 * java.nio.file.Files#newDirectoryStream(Path) newDirectoryStream} method to
1114 * open a directory and iterate over the names of the files in the directory.
1115 * This may use less resources when working with very large directories, and
1116 * may be more responsive when working with remote directories.
1117 *
1118 * @return An array of strings naming the files and directories in the
1119 * directory denoted by this abstract pathname. The array will be
1120 * empty if the directory is empty. Returns {@code null} if
1121 * this abstract pathname does not denote a directory, or if an
1122 * I/O error occurs.
1123 *
1124 * @throws SecurityException
1125 * If a security manager exists and its {@link
1126 * SecurityManager#checkRead(String)} method denies read access to
1127 * the directory
1128 */
1129 public String[] list() {
1130 SecurityManager security = System.getSecurityManager();
1131 if (security != null) {
1132 security.checkRead(path);
1133 }
1134 if (isInvalid()) {
1135 return null;
1136 }
1137 return fs.list(this);
1138 }
1139
1140 /**
1141 * Returns an array of strings naming the files and directories in the
1142 * directory denoted by this abstract pathname that satisfy the specified
1143 * filter. The behavior of this method is the same as that of the
1144 * {@link #list()} method, except that the strings in the returned array
1145 * must satisfy the filter. If the given {@code filter} is {@code null}
1146 * then all names are accepted. Otherwise, a name satisfies the filter if
1147 * and only if the value {@code true} results when the {@link
1148 * FilenameFilter#accept FilenameFilter.accept(File, String)} method
1149 * of the filter is invoked on this abstract pathname and the name of a
1150 * file or directory in the directory that it denotes.
1151 *
1152 * @param filter
1153 * A filename filter
1154 *
1155 * @return An array of strings naming the files and directories in the
1156 * directory denoted by this abstract pathname that were accepted
1157 * by the given {@code filter}. The array will be empty if the
1158 * directory is empty or if no names were accepted by the filter.
1159 * Returns {@code null} if this abstract pathname does not denote
1160 * a directory, or if an I/O error occurs.
1161 *
1162 * @throws SecurityException
1163 * If a security manager exists and its {@link
1164 * SecurityManager#checkRead(String)} method denies read access to
1165 * the directory
1166 *
1167 * @see java.nio.file.Files#newDirectoryStream(Path,String)
1168 */
1169 public String[] list(FilenameFilter filter) {
1170 String names[] = list();
1171 if ((names == null) || (filter == null)) {
1172 return names;
1173 }
1174 List<String> v = new ArrayList<>();
1175 for (int i = 0 ; i < names.length ; i++) {
1176 if (filter.accept(this, names[i])) {
1177 v.add(names[i]);
1178 }
1179 }
1180 return v.toArray(new String[v.size()]);
1181 }
1182
1183 /**
1184 * Returns an array of abstract pathnames denoting the files in the
1185 * directory denoted by this abstract pathname.
1186 *
1187 * <p> If this abstract pathname does not denote a directory, then this
1188 * method returns {@code null}. Otherwise an array of {@code File} objects
1189 * is returned, one for each file or directory in the directory. Pathnames
1190 * denoting the directory itself and the directory's parent directory are
1191 * not included in the result. Each resulting abstract pathname is
1192 * constructed from this abstract pathname using the {@link #File(File,
1193 * String) File(File, String)} constructor. Therefore if this
1194 * pathname is absolute then each resulting pathname is absolute; if this
1195 * pathname is relative then each resulting pathname will be relative to
1196 * the same directory.
1197 *
1198 * <p> There is no guarantee that the name strings in the resulting array
1199 * will appear in any specific order; they are not, in particular,
1200 * guaranteed to appear in alphabetical order.
1201 *
1202 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1203 * java.nio.file.Files#newDirectoryStream(Path) newDirectoryStream} method
1204 * to open a directory and iterate over the names of the files in the
1205 * directory. This may use less resources when working with very large
1206 * directories.
1207 *
1208 * @return An array of abstract pathnames denoting the files and
1209 * directories in the directory denoted by this abstract pathname.
1210 * The array will be empty if the directory is empty. Returns
1211 * {@code null} if this abstract pathname does not denote a
1212 * directory, or if an I/O error occurs.
1213 *
1214 * @throws SecurityException
1215 * If a security manager exists and its {@link
1216 * SecurityManager#checkRead(String)} method denies read access to
1217 * the directory
1218 *
1219 * @since 1.2
1220 */
1221 public File[] listFiles() {
1222 String[] ss = list();
1223 if (ss == null) return null;
1224 int n = ss.length;
1225 File[] fs = new File[n];
1226 for (int i = 0; i < n; i++) {
1227 fs[i] = new File(ss[i], this);
1228 }
1229 return fs;
1230 }
1231
1232 /**
1233 * Returns an array of abstract pathnames denoting the files and
1234 * directories in the directory denoted by this abstract pathname that
1235 * satisfy the specified filter. The behavior of this method is the same
1236 * as that of the {@link #listFiles()} method, except that the pathnames in
1237 * the returned array must satisfy the filter. If the given {@code filter}
1238 * is {@code null} then all pathnames are accepted. Otherwise, a pathname
1239 * satisfies the filter if and only if the value {@code true} results when
1240 * the {@link FilenameFilter#accept
1241 * FilenameFilter.accept(File, String)} method of the filter is
1242 * invoked on this abstract pathname and the name of a file or directory in
1243 * the directory that it denotes.
1244 *
1245 * @param filter
1246 * A filename filter
1247 *
1248 * @return An array of abstract pathnames denoting the files and
1249 * directories in the directory denoted by this abstract pathname.
1250 * The array will be empty if the directory is empty. Returns
1251 * {@code null} if this abstract pathname does not denote a
1252 * directory, or if an I/O error occurs.
1253 *
1254 * @throws SecurityException
1255 * If a security manager exists and its {@link
1256 * SecurityManager#checkRead(String)} method denies read access to
1257 * the directory
1258 *
1259 * @since 1.2
1260 * @see java.nio.file.Files#newDirectoryStream(Path,String)
1261 */
1262 public File[] listFiles(FilenameFilter filter) {
1263 String ss[] = list();
1264 if (ss == null) return null;
1265 ArrayList<File> files = new ArrayList<>();
1266 for (String s : ss)
1267 if ((filter == null) || filter.accept(this, s))
1268 files.add(new File(s, this));
1269 return files.toArray(new File[files.size()]);
1270 }
1271
1272 /**
1273 * Returns an array of abstract pathnames denoting the files and
1274 * directories in the directory denoted by this abstract pathname that
1275 * satisfy the specified filter. The behavior of this method is the same
1276 * as that of the {@link #listFiles()} method, except that the pathnames in
1277 * the returned array must satisfy the filter. If the given {@code filter}
1278 * is {@code null} then all pathnames are accepted. Otherwise, a pathname
1279 * satisfies the filter if and only if the value {@code true} results when
1280 * the {@link FileFilter#accept FileFilter.accept(File)} method of the
1281 * filter is invoked on the pathname.
1282 *
1283 * @param filter
1284 * A file filter
1285 *
1286 * @return An array of abstract pathnames denoting the files and
1287 * directories in the directory denoted by this abstract pathname.
1288 * The array will be empty if the directory is empty. Returns
1289 * {@code null} if this abstract pathname does not denote a
1290 * directory, or if an I/O error occurs.
1291 *
1292 * @throws SecurityException
1293 * If a security manager exists and its {@link
1294 * SecurityManager#checkRead(String)} method denies read access to
1295 * the directory
1296 *
1297 * @since 1.2
1298 * @see java.nio.file.Files#newDirectoryStream(Path,java.nio.file.DirectoryStream.Filter)
1299 */
1300 public File[] listFiles(FileFilter filter) {
1301 String ss[] = list();
1302 if (ss == null) return null;
1303 ArrayList<File> files = new ArrayList<>();
1304 for (String s : ss) {
1305 File f = new File(s, this);
1306 if ((filter == null) || filter.accept(f))
1307 files.add(f);
1308 }
1309 return files.toArray(new File[files.size()]);
1310 }
1311
1312 /**
1313 * Creates the directory named by this abstract pathname.
1314 *
1315 * @return {@code true} if and only if the directory was
1316 * created; {@code false} otherwise
1317 *
1318 * @throws SecurityException
1319 * If a security manager exists and its {@link
1320 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1321 * method does not permit the named directory to be created
1322 */
1323 public boolean mkdir() {
1324 SecurityManager security = System.getSecurityManager();
1325 if (security != null) {
1326 security.checkWrite(path);
1327 }
1328 if (isInvalid()) {
1329 return false;
1330 }
1331 return fs.createDirectory(this);
1332 }
1333
1334 /**
1335 * Creates the directory named by this abstract pathname, including any
1336 * necessary but nonexistent parent directories. Note that if this
1337 * operation fails it may have succeeded in creating some of the necessary
1338 * parent directories.
1339 *
1340 * @return {@code true} if and only if the directory was created,
1341 * along with all necessary parent directories; {@code false}
1342 * otherwise
1343 *
1344 * @throws SecurityException
1345 * If a security manager exists and its {@link
1346 * java.lang.SecurityManager#checkRead(java.lang.String)}
1347 * method does not permit verification of the existence of the
1348 * named directory and all necessary parent directories; or if
1349 * the {@link
1350 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1351 * method does not permit the named directory and all necessary
1352 * parent directories to be created
1353 */
1354 public boolean mkdirs() {
1355 if (exists()) {
1356 return false;
1357 }
1358 if (mkdir()) {
1359 return true;
1360 }
1361 File canonFile = null;
1362 try {
1363 canonFile = getCanonicalFile();
1364 } catch (IOException e) {
1365 return false;
1366 }
1367
1368 File parent = canonFile.getParentFile();
1369 return (parent != null && (parent.mkdirs() || parent.exists()) &&
1370 canonFile.mkdir());
1371 }
1372
1373 /**
1374 * Renames the file denoted by this abstract pathname.
1375 *
1376 * <p> Many aspects of the behavior of this method are inherently
1377 * platform-dependent: The rename operation might not be able to move a
1378 * file from one filesystem to another, it might not be atomic, and it
1379 * might not succeed if a file with the destination abstract pathname
1380 * already exists. The return value should always be checked to make sure
1381 * that the rename operation was successful.
1382 *
1383 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1384 * java.nio.file.Files#move move} method to move or rename a file in a
1385 * platform independent manner.
1386 *
1387 * @param dest The new abstract pathname for the named file
1388 *
1389 * @return {@code true} if and only if the renaming succeeded;
1390 * {@code false} otherwise
1391 *
1392 * @throws SecurityException
1393 * If a security manager exists and its {@link
1394 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1395 * method denies write access to either the old or new pathnames
1396 *
1397 * @throws NullPointerException
1398 * If parameter {@code dest} is {@code null}
1399 */
1400 public boolean renameTo(File dest) {
1401 if (dest == null) {
1402 throw new NullPointerException();
1403 }
1404 SecurityManager security = System.getSecurityManager();
1405 if (security != null) {
1406 security.checkWrite(path);
1407 security.checkWrite(dest.path);
1408 }
1409 if (this.isInvalid() || dest.isInvalid()) {
1410 return false;
1411 }
1412 return fs.rename(this, dest);
1413 }
1414
1415 /**
1416 * Sets the last-modified time of the file or directory named by this
1417 * abstract pathname.
1418 *
1419 * <p> All platforms support file-modification times to the nearest second,
1420 * but some provide more precision. The argument will be truncated to fit
1421 * the supported precision. If the operation succeeds and no intervening
1422 * operations on the file take place, then the next invocation of the
1423 * {@link #lastModified} method will return the (possibly
1424 * truncated) {@code time} argument that was passed to this method.
1425 *
1426 * @param time The new last-modified time, measured in milliseconds since
1427 * the epoch (00:00:00 GMT, January 1, 1970)
1428 *
1429 * @return {@code true} if and only if the operation succeeded;
1430 * {@code false} otherwise
1431 *
1432 * @throws IllegalArgumentException If the argument is negative
1433 *
1434 * @throws SecurityException
1435 * If a security manager exists and its {@link
1436 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1437 * method denies write access to the named file
1438 *
1439 * @since 1.2
1440 */
1441 public boolean setLastModified(long time) {
1442 if (time < 0) throw new IllegalArgumentException("Negative time");
1443 SecurityManager security = System.getSecurityManager();
1444 if (security != null) {
1445 security.checkWrite(path);
1446 }
1447 if (isInvalid()) {
1448 return false;
1449 }
1450 return fs.setLastModifiedTime(this, time);
1451 }
1452
1453 /**
1454 * Marks the file or directory named by this abstract pathname so that
1455 * only read operations are allowed. After invoking this method the file
1456 * or directory will not change until it is either deleted or marked
1457 * to allow write access. On some platforms it may be possible to start the
1458 * Java virtual machine with special privileges that allow it to modify
1459 * files that are marked read-only. Whether or not a read-only file or
1460 * directory may be deleted depends upon the underlying system.
1461 *
1462 * @return {@code true} if and only if the operation succeeded;
1463 * {@code false} otherwise
1464 *
1465 * @throws SecurityException
1466 * If a security manager exists and its {@link
1467 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1468 * method denies write access to the named file
1469 *
1470 * @since 1.2
1471 */
1472 public boolean setReadOnly() {
1473 SecurityManager security = System.getSecurityManager();
1474 if (security != null) {
1475 security.checkWrite(path);
1476 }
1477 if (isInvalid()) {
1478 return false;
1479 }
1480 return fs.setReadOnly(this);
1481 }
1482
1483 /**
1484 * Sets the owner's or everybody's write permission for this abstract
1485 * pathname. On some platforms it may be possible to start the Java virtual
1486 * machine with special privileges that allow it to modify files that
1487 * disallow write operations.
1488 *
1489 * <p> The {@link java.nio.file.Files} class defines methods that operate on
1490 * file attributes including file permissions. This may be used when finer
1491 * manipulation of file permissions is required.
1492 *
1493 * @param writable
1494 * If {@code true}, sets the access permission to allow write
1495 * operations; if {@code false} to disallow write operations
1496 *
1497 * @param ownerOnly
1498 * If {@code true}, the write permission applies only to the
1499 * owner's write permission; otherwise, it applies to everybody. If
1500 * the underlying file system can not distinguish the owner's write
1501 * permission from that of others, then the permission will apply to
1502 * everybody, regardless of this value.
1503 *
1504 * @return {@code true} if and only if the operation succeeded. The
1505 * operation will fail if the user does not have permission to change
1506 * the access permissions of this abstract pathname.
1507 *
1508 * @throws SecurityException
1509 * If a security manager exists and its {@link
1510 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1511 * method denies write access to the named file
1512 *
1513 * @since 1.6
1514 */
1515 public boolean setWritable(boolean writable, boolean ownerOnly) {
1516 SecurityManager security = System.getSecurityManager();
1517 if (security != null) {
1518 security.checkWrite(path);
1519 }
1520 if (isInvalid()) {
1521 return false;
1522 }
1523 return fs.setPermission(this, FileSystem.ACCESS_WRITE, writable, ownerOnly);
1524 }
1525
1526 /**
1527 * A convenience method to set the owner's write permission for this abstract
1528 * pathname. On some platforms it may be possible to start the Java virtual
1529 * machine with special privileges that allow it to modify files that
1530 * disallow write operations.
1531 *
1532 * <p> An invocation of this method of the form {@code file.setWritable(arg)}
1533 * behaves in exactly the same way as the invocation
1534 *
1535 * <pre>{@code
1536 * file.setWritable(arg, true)
1537 * }</pre>
1538 *
1539 * @param writable
1540 * If {@code true}, sets the access permission to allow write
1541 * operations; if {@code false} to disallow write operations
1542 *
1543 * @return {@code true} if and only if the operation succeeded. The
1544 * operation will fail if the user does not have permission to
1545 * change the access permissions of this abstract pathname.
1546 *
1547 * @throws SecurityException
1548 * If a security manager exists and its {@link
1549 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1550 * method denies write access to the file
1551 *
1552 * @since 1.6
1553 */
1554 public boolean setWritable(boolean writable) {
1555 return setWritable(writable, true);
1556 }
1557
1558 /**
1559 * Sets the owner's or everybody's read permission for this abstract
1560 * pathname. On some platforms it may be possible to start the Java virtual
1561 * machine with special privileges that allow it to read files that are
1562 * marked as unreadable.
1563 *
1564 * <p> The {@link java.nio.file.Files} class defines methods that operate on
1565 * file attributes including file permissions. This may be used when finer
1566 * manipulation of file permissions is required.
1567 *
1568 * @param readable
1569 * If {@code true}, sets the access permission to allow read
1570 * operations; if {@code false} to disallow read operations
1571 *
1572 * @param ownerOnly
1573 * If {@code true}, the read permission applies only to the
1574 * owner's read permission; otherwise, it applies to everybody. If
1575 * the underlying file system can not distinguish the owner's read
1576 * permission from that of others, then the permission will apply to
1577 * everybody, regardless of this value.
1578 *
1579 * @return {@code true} if and only if the operation succeeded. The
1580 * operation will fail if the user does not have permission to
1581 * change the access permissions of this abstract pathname. If
1582 * {@code readable} is {@code false} and the underlying
1583 * file system does not implement a read permission, then the
1584 * operation will fail.
1585 *
1586 * @throws SecurityException
1587 * If a security manager exists and its {@link
1588 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1589 * method denies write access to the file
1590 *
1591 * @since 1.6
1592 */
1593 public boolean setReadable(boolean readable, boolean ownerOnly) {
1594 SecurityManager security = System.getSecurityManager();
1595 if (security != null) {
1596 security.checkWrite(path);
1597 }
1598 if (isInvalid()) {
1599 return false;
1600 }
1601 return fs.setPermission(this, FileSystem.ACCESS_READ, readable, ownerOnly);
1602 }
1603
1604 /**
1605 * A convenience method to set the owner's read permission for this abstract
1606 * pathname. On some platforms it may be possible to start the Java virtual
1607 * machine with special privileges that allow it to read files that are
1608 * marked as unreadable.
1609 *
1610 * <p>An invocation of this method of the form {@code file.setReadable(arg)}
1611 * behaves in exactly the same way as the invocation
1612 *
1613 * <pre>{@code
1614 * file.setReadable(arg, true)
1615 * }</pre>
1616 *
1617 * @param readable
1618 * If {@code true}, sets the access permission to allow read
1619 * operations; if {@code false} to disallow read operations
1620 *
1621 * @return {@code true} if and only if the operation succeeded. The
1622 * operation will fail if the user does not have permission to
1623 * change the access permissions of this abstract pathname. If
1624 * {@code readable} is {@code false} and the underlying
1625 * file system does not implement a read permission, then the
1626 * operation will fail.
1627 *
1628 * @throws SecurityException
1629 * If a security manager exists and its {@link
1630 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1631 * method denies write access to the file
1632 *
1633 * @since 1.6
1634 */
1635 public boolean setReadable(boolean readable) {
1636 return setReadable(readable, true);
1637 }
1638
1639 /**
1640 * Sets the owner's or everybody's execute permission for this abstract
1641 * pathname. On some platforms it may be possible to start the Java virtual
1642 * machine with special privileges that allow it to execute files that are
1643 * not marked executable.
1644 *
1645 * <p> The {@link java.nio.file.Files} class defines methods that operate on
1646 * file attributes including file permissions. This may be used when finer
1647 * manipulation of file permissions is required.
1648 *
1649 * @param executable
1650 * If {@code true}, sets the access permission to allow execute
1651 * operations; if {@code false} to disallow execute operations
1652 *
1653 * @param ownerOnly
1654 * If {@code true}, the execute permission applies only to the
1655 * owner's execute permission; otherwise, it applies to everybody.
1656 * If the underlying file system can not distinguish the owner's
1657 * execute permission from that of others, then the permission will
1658 * apply to everybody, regardless of this value.
1659 *
1660 * @return {@code true} if and only if the operation succeeded. The
1661 * operation will fail if the user does not have permission to
1662 * change the access permissions of this abstract pathname. If
1663 * {@code executable} is {@code false} and the underlying
1664 * file system does not implement an execute permission, then the
1665 * operation will fail.
1666 *
1667 * @throws SecurityException
1668 * If a security manager exists and its {@link
1669 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1670 * method denies write access to the file
1671 *
1672 * @since 1.6
1673 */
1674 public boolean setExecutable(boolean executable, boolean ownerOnly) {
1675 SecurityManager security = System.getSecurityManager();
1676 if (security != null) {
1677 security.checkWrite(path);
1678 }
1679 if (isInvalid()) {
1680 return false;
1681 }
1682 return fs.setPermission(this, FileSystem.ACCESS_EXECUTE, executable, ownerOnly);
1683 }
1684
1685 /**
1686 * A convenience method to set the owner's execute permission for this
1687 * abstract pathname. On some platforms it may be possible to start the Java
1688 * virtual machine with special privileges that allow it to execute files
1689 * that are not marked executable.
1690 *
1691 * <p>An invocation of this method of the form {@code file.setExcutable(arg)}
1692 * behaves in exactly the same way as the invocation
1693 *
1694 * <pre>{@code
1695 * file.setExecutable(arg, true)
1696 * }</pre>
1697 *
1698 * @param executable
1699 * If {@code true}, sets the access permission to allow execute
1700 * operations; if {@code false} to disallow execute operations
1701 *
1702 * @return {@code true} if and only if the operation succeeded. The
1703 * operation will fail if the user does not have permission to
1704 * change the access permissions of this abstract pathname. If
1705 * {@code executable} is {@code false} and the underlying
1706 * file system does not implement an execute permission, then the
1707 * operation will fail.
1708 *
1709 * @throws SecurityException
1710 * If a security manager exists and its {@link
1711 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1712 * method denies write access to the file
1713 *
1714 * @since 1.6
1715 */
1716 public boolean setExecutable(boolean executable) {
1717 return setExecutable(executable, true);
1718 }
1719
1720 /**
1721 * Tests whether the application can execute the file denoted by this
1722 * abstract pathname. On some platforms it may be possible to start the
1723 * Java virtual machine with special privileges that allow it to execute
1724 * files that are not marked executable. Consequently this method may return
1725 * {@code true} even though the file does not have execute permissions.
1726 *
1727 * @return {@code true} if and only if the abstract pathname exists
1728 * <em>and</em> the application is allowed to execute the file
1729 *
1730 * @throws SecurityException
1731 * If a security manager exists and its {@link
1732 * java.lang.SecurityManager#checkExec(java.lang.String)}
1733 * method denies execute access to the file
1734 *
1735 * @since 1.6
1736 */
1737 public boolean canExecute() {
1738 SecurityManager security = System.getSecurityManager();
1739 if (security != null) {
1740 security.checkExec(path);
1741 }
1742 if (isInvalid()) {
1743 return false;
1744 }
1745 return fs.checkAccess(this, FileSystem.ACCESS_EXECUTE);
1746 }
1747
1748
1749 /* -- Filesystem interface -- */
1750
1751 /**
1752 * List the available filesystem roots.
1753 *
1754 * <p> A particular Java platform may support zero or more
1755 * hierarchically-organized file systems. Each file system has a
1756 * {@code root} directory from which all other files in that file system
1757 * can be reached. Windows platforms, for example, have a root directory
1758 * for each active drive; UNIX platforms have a single root directory,
1759 * namely {@code "/"}. The set of available filesystem roots is affected
1760 * by various system-level operations such as the insertion or ejection of
1761 * removable media and the disconnecting or unmounting of physical or
1762 * virtual disk drives.
1763 *
1764 * <p> This method returns an array of {@code File} objects that denote the
1765 * root directories of the available filesystem roots. It is guaranteed
1766 * that the canonical pathname of any file physically present on the local
1767 * machine will begin with one of the roots returned by this method.
1768 *
1769 * <p> The canonical pathname of a file that resides on some other machine
1770 * and is accessed via a remote-filesystem protocol such as SMB or NFS may
1771 * or may not begin with one of the roots returned by this method. If the
1772 * pathname of a remote file is syntactically indistinguishable from the
1773 * pathname of a local file then it will begin with one of the roots
1774 * returned by this method. Thus, for example, {@code File} objects
1775 * denoting the root directories of the mapped network drives of a Windows
1776 * platform will be returned by this method, while {@code File} objects
1777 * containing UNC pathnames will not be returned by this method.
1778 *
1779 * <p> Unlike most methods in this class, this method does not throw
1780 * security exceptions. If a security manager exists and its {@link
1781 * SecurityManager#checkRead(String)} method denies read access to a
1782 * particular root directory, then that directory will not appear in the
1783 * result.
1784 *
1785 * @return An array of {@code File} objects denoting the available
1786 * filesystem roots, or {@code null} if the set of roots could not
1787 * be determined. The array will be empty if there are no
1788 * filesystem roots.
1789 *
1790 * @since 1.2
1791 * @see java.nio.file.FileStore
1792 */
1793 public static File[] listRoots() {
1794 return fs.listRoots();
1795 }
1796
1797
1798 /* -- Disk usage -- */
1799
1800 /**
1801 * Returns the size of the partition <a href="#partName">named</a> by this
1802 * abstract pathname. If the total number of bytes in the partition is
1803 * greater than {@link Long#MAX_VALUE}, then {@code Long.MAX_VALUE} will be
1804 * returned.
1805 *
1806 * @return The size, in bytes, of the partition or {@code 0L} if this
1807 * abstract pathname does not name a partition
1808 *
1809 * @throws SecurityException
1810 * If a security manager has been installed and it denies
1811 * {@link RuntimePermission}{@code ("getFileSystemAttributes")}
1812 * or its {@link SecurityManager#checkRead(String)} method denies
1813 * read access to the file named by this abstract pathname
1814 *
1815 * @since 1.6
1816 * @see FileStore#getTotalSpace
1817 */
1818 public long getTotalSpace() {
1819 SecurityManager sm = System.getSecurityManager();
1820 if (sm != null) {
1821 sm.checkPermission(new RuntimePermission("getFileSystemAttributes"));
1822 sm.checkRead(path);
1823 }
1824 if (isInvalid()) {
1825 return 0L;
1826 }
1827 long space = fs.getSpace(this, FileSystem.SPACE_TOTAL);
1828 return space >= 0L ? space : Long.MAX_VALUE;
1829 }
1830
1831 /**
1832 * Returns the number of unallocated bytes in the partition <a
1833 * href="#partName">named</a> by this abstract path name. If the
1834 * number of unallocated bytes in the partition is greater than
1835 * {@link Long#MAX_VALUE}, then {@code Long.MAX_VALUE} will be returned.
1836 *
1837 * <p> The returned number of unallocated bytes is a hint, but not
1838 * a guarantee, that it is possible to use most or any of these
1839 * bytes. The number of unallocated bytes is most likely to be
1840 * accurate immediately after this call. It is likely to be made
1841 * inaccurate by any external I/O operations including those made
1842 * on the system outside of this virtual machine. This method
1843 * makes no guarantee that write operations to this file system
1844 * will succeed.
1845 *
1846 * @return The number of unallocated bytes on the partition or {@code 0L}
1847 * if the abstract pathname does not name a partition. This
1848 * value will be less than or equal to the total file system size
1849 * returned by {@link #getTotalSpace}.
1850 *
1851 * @throws SecurityException
1852 * If a security manager has been installed and it denies
1853 * {@link RuntimePermission}{@code ("getFileSystemAttributes")}
1854 * or its {@link SecurityManager#checkRead(String)} method denies
1855 * read access to the file named by this abstract pathname
1856 *
1857 * @since 1.6
1858 * @see FileStore#getUnallocatedSpace
1859 */
1860 public long getFreeSpace() {
1861 SecurityManager sm = System.getSecurityManager();
1862 if (sm != null) {
1863 sm.checkPermission(new RuntimePermission("getFileSystemAttributes"));
1864 sm.checkRead(path);
1865 }
1866 if (isInvalid()) {
1867 return 0L;
1868 }
1869 long space = fs.getSpace(this, FileSystem.SPACE_FREE);
1870 return space >= 0L ? space : Long.MAX_VALUE;
1871 }
1872
1873 /**
1874 * Returns the number of bytes available to this virtual machine on the
1875 * partition <a href="#partName">named</a> by this abstract pathname. If
1876 * the number of available bytes in the partition is greater than
1877 * {@link Long#MAX_VALUE}, then {@code Long.MAX_VALUE} will be returned.
1878 * When possible, this method checks for write permissions and other
1879 * operating system restrictions and will therefore usually provide a more
1880 * accurate estimate of how much new data can actually be written than
1881 * {@link #getFreeSpace}.
1882 *
1883 * <p> The returned number of available bytes is a hint, but not a
1884 * guarantee, that it is possible to use most or any of these bytes. The
1885 * number of available bytes is most likely to be accurate immediately
1886 * after this call. It is likely to be made inaccurate by any external
1887 * I/O operations including those made on the system outside of this
1888 * virtual machine. This method makes no guarantee that write operations
1889 * to this file system will succeed.
1890 *
1891 * @return The number of available bytes on the partition or {@code 0L}
1892 * if the abstract pathname does not name a partition. On
1893 * systems where this information is not available, this method
1894 * will be equivalent to a call to {@link #getFreeSpace}.
1895 *
1896 * @throws SecurityException
1897 * If a security manager has been installed and it denies
1898 * {@link RuntimePermission}{@code ("getFileSystemAttributes")}
1899 * or its {@link SecurityManager#checkRead(String)} method denies
1900 * read access to the file named by this abstract pathname
1901 *
1902 * @since 1.6
1903 * @see FileStore#getUsableSpace
1904 */
1905 public long getUsableSpace() {
1906 SecurityManager sm = System.getSecurityManager();
1907 if (sm != null) {
1908 sm.checkPermission(new RuntimePermission("getFileSystemAttributes"));
1909 sm.checkRead(path);
1910 }
1911 if (isInvalid()) {
1912 return 0L;
1913 }
1914 long space = fs.getSpace(this, FileSystem.SPACE_USABLE);
1915 return space >= 0L ? space : Long.MAX_VALUE;
1916 }
1917
1918 /* -- Temporary files -- */
1919
1920 private static class TempDirectory {
1921 private TempDirectory() { }
1922
1923 // temporary directory location
1924 private static final File tmpdir = new File(
1925 GetPropertyAction.privilegedGetProperty("java.io.tmpdir"));
1926 static File location() {
1927 return tmpdir;
1928 }
1929
1930 // file name generation
1931 private static final SecureRandom random = new SecureRandom();
1932 private static int shortenSubName(int subNameLength, int excess,
1933 int nameMin) {
1934 int newLength = Math.max(nameMin, subNameLength - excess);
1935 if (newLength < subNameLength) {
1936 return newLength;
1937 }
1938 return subNameLength;
1939 }
1940 static File generateFile(String prefix, String suffix, File dir)
1941 throws IOException
1942 {
1943 long n = random.nextLong();
1944 String nus = Long.toUnsignedString(n);
1945
1946 // Use only the file name from the supplied prefix
1947 prefix = (new File(prefix)).getName();
1948
1949 int prefixLength = prefix.length();
1950 int nusLength = nus.length();
1951 int suffixLength = suffix.length();;
1952
1953 String name;
1954 int nameMax = fs.getNameMax(dir.getPath());
1955 int excess = prefixLength + nusLength + suffixLength - nameMax;
1956 if (excess <= 0) {
1957 name = prefix + nus + suffix;
1958 } else {
1959 // Name exceeds the maximum path component length: shorten it
1960
1961 // Attempt to shorten the prefix length to no less then 3
1962 prefixLength = shortenSubName(prefixLength, excess, 3);
1963 excess = prefixLength + nusLength + suffixLength - nameMax;
1964
1965 if (excess > 0) {
1966 // Attempt to shorten the suffix length to no less than
1967 // 0 or 4 depending on whether it begins with a dot ('.')
1968 suffixLength = shortenSubName(suffixLength, excess,
1969 suffix.indexOf(".") == 0 ? 4 : 0);
1970 suffixLength = shortenSubName(suffixLength, excess, 3);
1971 excess = prefixLength + nusLength + suffixLength - nameMax;
1972 }
1973
1974 if (excess > 0 && excess <= nusLength - 5) {
1975 // Attempt to shorten the random character string length
1976 // to no less than 5
1977 nusLength = shortenSubName(nusLength, excess, 5);
1978 }
1979
1980 StringBuilder sb =
1981 new StringBuilder(prefixLength + nusLength + suffixLength);
1982 sb.append(prefixLength < prefix.length() ?
1983 prefix.substring(0, prefixLength) : prefix);
1984 sb.append(nusLength < nus.length() ?
1985 nus.substring(0, nusLength) : nus);
1986 sb.append(suffixLength < suffix.length() ?
1987 suffix.substring(0, suffixLength) : suffix);
1988 name = sb.toString();
1989 }
1990
1991 // Normalize the path component
1992 name = fs.normalize(name);
1993
1994 File f = new File(dir, name);
1995 if (!name.equals(f.getName()) || f.isInvalid()) {
1996 if (System.getSecurityManager() != null)
1997 throw new IOException("Unable to create temporary file");
1998 else
1999 throw new IOException("Unable to create temporary file, "
2000 + name);
2001 }
2002 return f;
2003 }
2004 }
2005
2006 /**
2007 * <p> Creates a new empty file in the specified directory, using the
2008 * given prefix and suffix strings to generate its name. If this method
2009 * returns successfully then it is guaranteed that:
2010 *
2011 * <ol>
2012 * <li> The file denoted by the returned abstract pathname did not exist
2013 * before this method was invoked, and
2014 * <li> Neither this method nor any of its variants will return the same
2015 * abstract pathname again in the current invocation of the virtual
2016 * machine.
2017 * </ol>
2018 *
2019 * This method provides only part of a temporary-file facility. To arrange
2020 * for a file created by this method to be deleted automatically, use the
2021 * {@link #deleteOnExit} method.
2022 *
2023 * <p> The {@code prefix} argument must be at least three characters
2024 * long. It is recommended that the prefix be a short, meaningful string
2025 * such as {@code "hjb"} or {@code "mail"}. The
2026 * {@code suffix} argument may be {@code null}, in which case the
2027 * suffix {@code ".tmp"} will be used.
2028 *
2029 * <p> To create the new file, the prefix and the suffix may first be
2030 * adjusted to fit the limitations of the underlying platform. If the
2031 * prefix is too long then it will be truncated, but its first three
2032 * characters will always be preserved. If the suffix is too long then it
2033 * too will be truncated, but if it begins with a period character
2034 * ({@code '.'}) then the period and the first three characters
2035 * following it will always be preserved. Once these adjustments have been
2036 * made the name of the new file will be generated by concatenating the
2037 * prefix, five or more internally-generated characters, and the suffix.
2038 *
2039 * <p> If the {@code directory} argument is {@code null} then the
2040 * system-dependent default temporary-file directory will be used. The
2041 * default temporary-file directory is specified by the system property
2042 * {@code java.io.tmpdir}. On UNIX systems the default value of this
2043 * property is typically {@code "/tmp"} or {@code "/var/tmp"}; on
2044 * Microsoft Windows systems it is typically {@code "C:\\WINNT\\TEMP"}. A different
2045 * value may be given to this system property when the Java virtual machine
2046 * is invoked, but programmatic changes to this property are not guaranteed
2047 * to have any effect upon the temporary directory used by this method.
2048 *
2049 * @param prefix The prefix string to be used in generating the file's
2050 * name; must be at least three characters long
2051 *
2052 * @param suffix The suffix string to be used in generating the file's
2053 * name; may be {@code null}, in which case the
2054 * suffix {@code ".tmp"} will be used
2055 *
2056 * @param directory The directory in which the file is to be created, or
2057 * {@code null} if the default temporary-file
2058 * directory is to be used
2059 *
2060 * @return An abstract pathname denoting a newly-created empty file
2061 *
2062 * @throws IllegalArgumentException
2063 * If the {@code prefix} argument contains fewer than three
2064 * characters
2065 *
2066 * @throws IOException If a file could not be created
2067 *
2068 * @throws SecurityException
2069 * If a security manager exists and its {@link
2070 * java.lang.SecurityManager#checkWrite(java.lang.String)}
2071 * method does not allow a file to be created
2072 *
2073 * @since 1.2
2074 */
2075 public static File createTempFile(String prefix, String suffix,
2076 File directory)
2077 throws IOException
2078 {
2079 if (prefix.length() < 3) {
2080 throw new IllegalArgumentException("Prefix string \"" + prefix +
2081 "\" too short: length must be at least 3");
2082 }
2083 if (suffix == null)
2084 suffix = ".tmp";
2085
2086 File tmpdir = (directory != null) ? directory
2087 : TempDirectory.location();
2088 SecurityManager sm = System.getSecurityManager();
2089 File f;
2090 do {
2091 f = TempDirectory.generateFile(prefix, suffix, tmpdir);
2092
2093 if (sm != null) {
2094 try {
2095 sm.checkWrite(f.getPath());
2096 } catch (SecurityException se) {
2097 // don't reveal temporary directory location
2098 if (directory == null)
2099 throw new SecurityException("Unable to create temporary file");
2100 throw se;
2101 }
2102 }
2103 } while ((fs.getBooleanAttributes(f) & FileSystem.BA_EXISTS) != 0);
2104
2105 if (!fs.createFileExclusively(f.getPath()))
2106 throw new IOException("Unable to create temporary file");
2107
2108 return f;
2109 }
2110
2111 /**
2112 * Creates an empty file in the default temporary-file directory, using
2113 * the given prefix and suffix to generate its name. Invoking this method
2114 * is equivalent to invoking {@link #createTempFile(java.lang.String,
2115 * java.lang.String, java.io.File)
2116 * createTempFile(prefix, suffix, null)}.
2117 *
2118 * <p> The {@link
2119 * java.nio.file.Files#createTempFile(String,String,java.nio.file.attribute.FileAttribute[])
2120 * Files.createTempFile} method provides an alternative method to create an
2121 * empty file in the temporary-file directory. Files created by that method
2122 * may have more restrictive access permissions to files created by this
2123 * method and so may be more suited to security-sensitive applications.
2124 *
2125 * @param prefix The prefix string to be used in generating the file's
2126 * name; must be at least three characters long
2127 *
2128 * @param suffix The suffix string to be used in generating the file's
2129 * name; may be {@code null}, in which case the
2130 * suffix {@code ".tmp"} will be used
2131 *
2132 * @return An abstract pathname denoting a newly-created empty file
2133 *
2134 * @throws IllegalArgumentException
2135 * If the {@code prefix} argument contains fewer than three
2136 * characters
2137 *
2138 * @throws IOException If a file could not be created
2139 *
2140 * @throws SecurityException
2141 * If a security manager exists and its {@link
2142 * java.lang.SecurityManager#checkWrite(java.lang.String)}
2143 * method does not allow a file to be created
2144 *
2145 * @since 1.2
2146 * @see java.nio.file.Files#createTempDirectory(String,FileAttribute[])
2147 */
2148 public static File createTempFile(String prefix, String suffix)
2149 throws IOException
2150 {
2151 return createTempFile(prefix, suffix, null);
2152 }
2153
2154 /* -- Basic infrastructure -- */
2155
2156 /**
2157 * Compares two abstract pathnames lexicographically. The ordering
2158 * defined by this method depends upon the underlying system. On UNIX
2159 * systems, alphabetic case is significant in comparing pathnames; on Microsoft Windows
2160 * systems it is not.
2161 *
2162 * @param pathname The abstract pathname to be compared to this abstract
2163 * pathname
2164 *
2165 * @return Zero if the argument is equal to this abstract pathname, a
2166 * value less than zero if this abstract pathname is
2167 * lexicographically less than the argument, or a value greater
2168 * than zero if this abstract pathname is lexicographically
2169 * greater than the argument
2170 *
2171 * @since 1.2
2172 */
2173 public int compareTo(File pathname) {
2174 return fs.compare(this, pathname);
2175 }
2176
2177 /**
2178 * Tests this abstract pathname for equality with the given object.
2179 * Returns {@code true} if and only if the argument is not
2180 * {@code null} and is an abstract pathname that denotes the same file
2181 * or directory as this abstract pathname. Whether or not two abstract
2182 * pathnames are equal depends upon the underlying system. On UNIX
2183 * systems, alphabetic case is significant in comparing pathnames; on Microsoft Windows
2184 * systems it is not.
2185 *
2186 * @param obj The object to be compared with this abstract pathname
2187 *
2188 * @return {@code true} if and only if the objects are the same;
2189 * {@code false} otherwise
2190 */
2191 public boolean equals(Object obj) {
2192 if ((obj != null) && (obj instanceof File)) {
2193 return compareTo((File)obj) == 0;
2194 }
2195 return false;
2196 }
2197
2198 /**
2199 * Computes a hash code for this abstract pathname. Because equality of
2200 * abstract pathnames is inherently system-dependent, so is the computation
2201 * of their hash codes. On UNIX systems, the hash code of an abstract
2202 * pathname is equal to the exclusive <em>or</em> of the hash code
2203 * of its pathname string and the decimal value
2204 * {@code 1234321}. On Microsoft Windows systems, the hash
2205 * code is equal to the exclusive <em>or</em> of the hash code of
2206 * its pathname string converted to lower case and the decimal
2207 * value {@code 1234321}. Locale is not taken into account on
2208 * lowercasing the pathname string.
2209 *
2210 * @return A hash code for this abstract pathname
2211 */
2212 public int hashCode() {
2213 return fs.hashCode(this);
2214 }
2215
2216 /**
2217 * Returns the pathname string of this abstract pathname. This is just the
2218 * string returned by the {@link #getPath} method.
2219 *
2220 * @return The string form of this abstract pathname
2221 */
2222 public String toString() {
2223 return getPath();
2224 }
2225
2226 /**
2227 * WriteObject is called to save this filename.
2228 * The separator character is saved also so it can be replaced
2229 * in case the path is reconstituted on a different host type.
2230 *
2231 * @serialData Default fields followed by separator character.
2232 */
2233 @java.io.Serial
2234 private synchronized void writeObject(java.io.ObjectOutputStream s)
2235 throws IOException
2236 {
2237 s.defaultWriteObject();
2238 s.writeChar(separatorChar); // Add the separator character
2239 }
2240
2241 /**
2242 * readObject is called to restore this filename.
2243 * The original separator character is read. If it is different
2244 * than the separator character on this system, then the old separator
2245 * is replaced by the local separator.
2246 */
2247 @java.io.Serial
2248 private synchronized void readObject(java.io.ObjectInputStream s)
2249 throws IOException, ClassNotFoundException
2250 {
2251 ObjectInputStream.GetField fields = s.readFields();
2252 String pathField = (String)fields.get("path", null);
2253 char sep = s.readChar(); // read the previous separator char
2254 if (sep != separatorChar)
2255 pathField = pathField.replace(sep, separatorChar);
2256 String path = fs.normalize(pathField);
2257 UNSAFE.putReference(this, PATH_OFFSET, path);
2258 UNSAFE.putIntVolatile(this, PREFIX_LENGTH_OFFSET, fs.prefixLength(path));
2259 }
2260
2261 private static final jdk.internal.misc.Unsafe UNSAFE
2262 = jdk.internal.misc.Unsafe.getUnsafe();
2263 private static final long PATH_OFFSET
2264 = UNSAFE.objectFieldOffset(File.class, "path");
2265 private static final long PREFIX_LENGTH_OFFSET
2266 = UNSAFE.objectFieldOffset(File.class, "prefixLength");
2267
2268 /** use serialVersionUID from JDK 1.0.2 for interoperability */
2269 @java.io.Serial
2270 private static final long serialVersionUID = 301077366599181567L;
2271
2272 // -- Integration with java.nio.file --
2273
2274 private transient volatile Path filePath;
2275
2276 /**
2277 * Returns a {@link Path java.nio.file.Path} object constructed from
2278 * this abstract path. The resulting {@code Path} is associated with the
2279 * {@link java.nio.file.FileSystems#getDefault default-filesystem}.
2280 *
2281 * <p> The first invocation of this method works as if invoking it were
2282 * equivalent to evaluating the expression:
2283 * <blockquote><pre>
2284 * {@link java.nio.file.FileSystems#getDefault FileSystems.getDefault}().{@link
2285 * java.nio.file.FileSystem#getPath getPath}(this.{@link #getPath getPath}());
2286 * </pre></blockquote>
2287 * Subsequent invocations of this method return the same {@code Path}.
2288 *
2289 * <p> If this abstract pathname is the empty abstract pathname then this
2290 * method returns a {@code Path} that may be used to access the current
2291 * user directory.
2292 *
2293 * @return a {@code Path} constructed from this abstract path
2294 *
2295 * @throws java.nio.file.InvalidPathException
2296 * if a {@code Path} object cannot be constructed from the abstract
2297 * path (see {@link java.nio.file.FileSystem#getPath FileSystem.getPath})
2298 *
2299 * @since 1.7
2300 * @see Path#toFile
2301 */
2302 public Path toPath() {
2303 Path result = filePath;
2304 if (result == null) {
2305 synchronized (this) {
2306 result = filePath;
2307 if (result == null) {
2308 result = FileSystems.getDefault().getPath(path);
2309 filePath = result;
2310 }
2311 }
2312 }
2313 return result;
2314 }
2315 }