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
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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
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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.FileSystems;
33 import java.nio.file.Path;
34 import java.security.SecureRandom;
35 import java.util.ArrayList;
36 import java.util.List;
37 import sun.security.action.GetPropertyAction;
38
39 /**
40 * An abstract representation of file and directory pathnames.
41 *
42 * <p> User interfaces and operating systems use system-dependent <em>pathname
43 * strings</em> to name files and directories. This class presents an
44 * abstract, system-independent view of hierarchical pathnames. An
45 * <em>abstract pathname</em> has two components:
46 *
47 * <ol>
48 * <li> An optional system-dependent <em>prefix</em> string,
49 * such as a disk-drive specifier, <code>"/"</code> for the UNIX root
50 * directory, or <code>"\\\\"</code> for a Microsoft Windows UNC pathname, and
51 * <li> A sequence of zero or more string <em>names</em>.
52 * </ol>
53 *
54 * The first name in an abstract pathname may be a directory name or, in the
55 * case of Microsoft Windows UNC pathnames, a hostname. Each subsequent name
56 * in an abstract pathname denotes a directory; the last name may denote
57 * either a directory or a file. The <em>empty</em> abstract pathname has no
58 * prefix and an empty name sequence.
59 *
60 * <p> The conversion of a pathname string to or from an abstract pathname is
61 * inherently system-dependent. When an abstract pathname is converted into a
62 * pathname string, each name is separated from the next by a single copy of
63 * the default <em>separator character</em>. The default name-separator
64 * character is defined by the system property <code>file.separator</code>, and
65 * is made available in the public static fields {@link
66 * #separator} and {@link #separatorChar} of this class.
67 * When a pathname string is converted into an abstract pathname, the names
68 * within it may be separated by the default name-separator character or by any
69 * other name-separator character that is supported by the underlying system.
70 *
71 * <p> A pathname, whether abstract or in string form, may be either
72 * <em>absolute</em> or <em>relative</em>. An absolute pathname is complete in
73 * that no other information is required in order to locate the file that it
74 * denotes. A relative pathname, in contrast, must be interpreted in terms of
75 * information taken from some other pathname. By default the classes in the
76 * <code>java.io</code> package always resolve relative pathnames against the
77 * current user directory. This directory is named by the system property
78 * <code>user.dir</code>, and is typically the directory in which the Java
79 * virtual machine was invoked.
80 *
81 * <p> The <em>parent</em> of an abstract pathname may be obtained by invoking
82 * the {@link #getParent} method of this class and consists of the pathname's
83 * prefix and each name in the pathname's name sequence except for the last.
84 * Each directory's absolute pathname is an ancestor of any {@code File}
85 * object with an absolute abstract pathname which begins with the directory's
86 * absolute pathname. For example, the directory denoted by the abstract
87 * pathname {@code "/usr"} is an ancestor of the directory denoted by the
88 * pathname {@code "/usr/local/bin"}.
89 *
90 * <p> The prefix concept is used to handle root directories on UNIX platforms,
91 * and drive specifiers, root directories and UNC pathnames on Microsoft Windows platforms,
92 * as follows:
93 *
94 * <ul>
95 *
96 * <li> For UNIX platforms, the prefix of an absolute pathname is always
97 * <code>"/"</code>. Relative pathnames have no prefix. The abstract pathname
98 * denoting the root directory has the prefix <code>"/"</code> and an empty
99 * name sequence.
100 *
101 * <li> For Microsoft Windows platforms, the prefix of a pathname that contains a drive
102 * specifier consists of the drive letter followed by <code>":"</code> and
103 * possibly followed by <code>"\\"</code> if the pathname is absolute. The
104 * prefix of a UNC pathname is <code>"\\\\"</code>; the hostname and the share
105 * name are the first two names in the name sequence. A relative pathname that
106 * does not specify a drive has no prefix.
107 *
108 * </ul>
109 *
110 * <p> Instances of this class may or may not denote an actual file-system
111 * object such as a file or a directory. If it does denote such an object
112 * then that object resides in a <i>partition</i>. A partition is an
113 * operating system-specific portion of storage for a file system. A single
114 * storage device (e.g. a physical disk-drive, flash memory, CD-ROM) may
115 * contain multiple partitions. The object, if any, will reside on the
116 * partition <a id="partName">named</a> by some ancestor of the absolute
117 * form of this pathname.
118 *
119 * <p> A file system may implement restrictions to certain operations on the
120 * actual file-system object, such as reading, writing, and executing. These
121 * restrictions are collectively known as <i>access permissions</i>. The file
122 * system may have multiple sets of access permissions on a single object.
123 * For example, one set may apply to the object's <i>owner</i>, and another
124 * may apply to all other users. The access permissions on an object may
125 * cause some methods in this class to fail.
126 *
127 * <p> Instances of the <code>File</code> class are immutable; that is, once
128 * created, the abstract pathname represented by a <code>File</code> object
129 * will never change.
130 *
131 * <h2>Interoperability with {@code java.nio.file} package</h2>
132 *
133 * <p> The <a href="../../java/nio/file/package-summary.html">{@code java.nio.file}</a>
134 * package defines interfaces and classes for the Java virtual machine to access
135 * files, file attributes, and file systems. This API may be used to overcome
136 * many of the limitations of the {@code java.io.File} class.
137 * The {@link #toPath toPath} method may be used to obtain a {@link
138 * Path} that uses the abstract path represented by a {@code File} object to
139 * locate a file. The resulting {@code Path} may be used with the {@link
140 * java.nio.file.Files} class to provide more efficient and extensive access to
141 * additional file operations, file attributes, and I/O exceptions to help
142 * diagnose errors when an operation on a file fails.
143 *
144 * @author unascribed
145 * @since 1.0
146 */
147
148 public class File
149 implements Serializable, Comparable<File>
150 {
151
152 /**
153 * The FileSystem object representing the platform's local file system.
154 */
155 private static final FileSystem fs = DefaultFileSystem.getFileSystem();
156
157 /**
158 * This abstract pathname's normalized pathname string. A normalized
159 * pathname string uses the default name-separator character and does not
160 * contain any duplicate or redundant separators.
161 *
162 * @serial
163 */
164 private final String path;
165
166 /**
167 * Enum type that indicates the status of a file path.
168 */
169 private static enum PathStatus { INVALID, CHECKED };
170
171 /**
172 * The flag indicating whether the file path is invalid.
173 */
174 private transient PathStatus status = null;
175
176 /**
177 * Check if the file has an invalid path. Currently, the inspection of
178 * a file path is very limited, and it only covers Nul character check.
179 * Returning true means the path is definitely invalid/garbage. But
180 * returning false does not guarantee that the path is valid.
181 *
182 * @return true if the file path is invalid.
183 */
184 final boolean isInvalid() {
185 if (status == null) {
186 status = (this.path.indexOf('\u0000') < 0) ? PathStatus.CHECKED
187 : PathStatus.INVALID;
188 }
189 return status == PathStatus.INVALID;
190 }
191
192 /**
193 * The length of this abstract pathname's prefix, or zero if it has no
194 * prefix.
195 */
196 private final transient int prefixLength;
197
198 /**
199 * Returns the length of this abstract pathname's prefix.
200 * For use by FileSystem classes.
201 */
202 int getPrefixLength() {
203 return prefixLength;
204 }
205
206 /**
207 * The system-dependent default name-separator character. This field is
208 * initialized to contain the first character of the value of the system
209 * property <code>file.separator</code>. On UNIX systems the value of this
210 * field is <code>'/'</code>; on Microsoft Windows systems it is <code>'\\'</code>.
211 *
212 * @see java.lang.System#getProperty(java.lang.String)
213 */
214 public static final char separatorChar = fs.getSeparator();
215
216 /**
217 * The system-dependent default name-separator character, represented as a
218 * string for convenience. This string contains a single character, namely
219 * {@link #separatorChar}.
220 */
221 public static final String separator = "" + separatorChar;
222
223 /**
224 * The system-dependent path-separator character. This field is
225 * initialized to contain the first character of the value of the system
226 * property <code>path.separator</code>. This character is used to
227 * separate filenames in a sequence of files given as a <em>path list</em>.
228 * On UNIX systems, this character is <code>':'</code>; on Microsoft Windows systems it
229 * is <code>';'</code>.
230 *
231 * @see java.lang.System#getProperty(java.lang.String)
232 */
233 public static final char pathSeparatorChar = fs.getPathSeparator();
234
235 /**
236 * The system-dependent path-separator character, represented as a string
237 * for convenience. This string contains a single character, namely
238 * {@link #pathSeparatorChar}.
239 */
240 public static final String pathSeparator = "" + pathSeparatorChar;
241
242
243 /* -- Constructors -- */
244
245 /**
246 * Internal constructor for already-normalized pathname strings.
247 */
248 private File(String pathname, int prefixLength) {
249 this.path = pathname;
250 this.prefixLength = prefixLength;
251 }
252
253 /**
254 * Internal constructor for already-normalized pathname strings.
255 * The parameter order is used to disambiguate this method from the
256 * public(File, String) constructor.
257 */
258 private File(String child, File parent) {
259 assert parent.path != null;
260 assert (!parent.path.isEmpty());
261 this.path = fs.resolve(parent.path, child);
262 this.prefixLength = parent.prefixLength;
263 }
264
265 /**
266 * Creates a new <code>File</code> instance by converting the given
267 * pathname string into an abstract pathname. If the given string is
268 * the empty string, then the result is the empty abstract pathname.
269 *
270 * @param pathname A pathname string
271 * @throws NullPointerException
272 * If the <code>pathname</code> argument is <code>null</code>
273 */
274 public File(String pathname) {
275 if (pathname == null) {
276 throw new NullPointerException();
277 }
278 this.path = fs.normalize(pathname);
279 this.prefixLength = fs.prefixLength(this.path);
280 }
281
282 /* Note: The two-argument File constructors do not interpret an empty
283 parent abstract pathname as the current user directory. An empty parent
284 instead causes the child to be resolved against the system-dependent
285 directory defined by the FileSystem.getDefaultParent method. On Unix
286 this default is "/", while on Microsoft Windows it is "\\". This is required for
287 compatibility with the original behavior of this class. */
288
289 /**
290 * Creates a new <code>File</code> instance from a parent pathname string
291 * and a child pathname string.
292 *
293 * <p> If <code>parent</code> is <code>null</code> then the new
294 * <code>File</code> instance is created as if by invoking the
295 * single-argument <code>File</code> constructor on the given
296 * <code>child</code> pathname string.
297 *
298 * <p> Otherwise the <code>parent</code> pathname string is taken to denote
299 * a directory, and the <code>child</code> pathname string is taken to
300 * denote either a directory or a file. If the <code>child</code> pathname
301 * string is absolute then it is converted into a relative pathname in a
302 * system-dependent way. If <code>parent</code> is the empty string then
303 * the new <code>File</code> instance is created by converting
304 * <code>child</code> into an abstract pathname and resolving the result
305 * against a system-dependent default directory. Otherwise each pathname
306 * string is converted into an abstract pathname and the child abstract
307 * pathname is resolved against the parent.
308 *
309 * @param parent The parent pathname string
310 * @param child The child pathname string
311 * @throws NullPointerException
312 * If <code>child</code> is <code>null</code>
313 */
314 public File(String parent, String child) {
315 if (child == null) {
316 throw new NullPointerException();
317 }
318 if (parent != null) {
319 if (parent.isEmpty()) {
320 this.path = fs.resolve(fs.getDefaultParent(),
321 fs.normalize(child));
322 } else {
323 this.path = fs.resolve(fs.normalize(parent),
324 fs.normalize(child));
325 }
326 } else {
327 this.path = fs.normalize(child);
328 }
329 this.prefixLength = fs.prefixLength(this.path);
330 }
331
332 /**
333 * Creates a new <code>File</code> instance from a parent abstract
334 * pathname and a child pathname string.
335 *
336 * <p> If <code>parent</code> is <code>null</code> then the new
337 * <code>File</code> instance is created as if by invoking the
338 * single-argument <code>File</code> constructor on the given
339 * <code>child</code> pathname string.
340 *
341 * <p> Otherwise the <code>parent</code> abstract pathname is taken to
342 * denote a directory, and the <code>child</code> pathname string is taken
343 * to denote either a directory or a file. If the <code>child</code>
344 * pathname string is absolute then it is converted into a relative
345 * pathname in a system-dependent way. If <code>parent</code> is the empty
346 * abstract pathname then the new <code>File</code> instance is created by
347 * converting <code>child</code> into an abstract pathname and resolving
348 * the result against a system-dependent default directory. Otherwise each
349 * pathname string is converted into an abstract pathname and the child
350 * abstract pathname is resolved against the parent.
351 *
352 * @param parent The parent abstract pathname
353 * @param child The child pathname string
354 * @throws NullPointerException
355 * If <code>child</code> is <code>null</code>
356 */
357 public File(File parent, String child) {
358 if (child == null) {
359 throw new NullPointerException();
360 }
361 if (parent != null) {
362 if (parent.path.isEmpty()) {
363 this.path = fs.resolve(fs.getDefaultParent(),
364 fs.normalize(child));
365 } else {
366 this.path = fs.resolve(parent.path,
367 fs.normalize(child));
368 }
369 } else {
370 this.path = fs.normalize(child);
371 }
372 this.prefixLength = fs.prefixLength(this.path);
373 }
374
375 /**
376 * Creates a new {@code File} instance by converting the given
377 * {@code file:} URI into an abstract pathname.
378 *
379 * <p> The exact form of a {@code file:} URI is system-dependent, hence
380 * the transformation performed by this constructor is also
381 * system-dependent.
382 *
383 * <p> For a given abstract pathname <i>f</i> it is guaranteed that
384 *
385 * <blockquote><code>
386 * new File(</code><i> f</i><code>.{@link #toURI()
387 * toURI}()).equals(</code><i> f</i><code>.{@link #getAbsoluteFile() getAbsoluteFile}())
388 * </code></blockquote>
389 *
390 * so long as the original abstract pathname, the URI, and the new abstract
391 * pathname are all created in (possibly different invocations of) the same
392 * Java virtual machine. This relationship typically does not hold,
393 * however, when a {@code file:} URI that is created in a virtual machine
394 * on one operating system is converted into an abstract pathname in a
395 * virtual machine on a different operating system.
396 *
397 * @param uri
398 * An absolute, hierarchical URI with a scheme equal to
399 * {@code "file"}, a non-empty path component, and undefined
400 * authority, query, and fragment components
401 *
402 * @throws NullPointerException
403 * If {@code uri} is {@code null}
404 *
405 * @throws IllegalArgumentException
406 * If the preconditions on the parameter do not hold
407 *
408 * @see #toURI()
409 * @see java.net.URI
410 * @since 1.4
411 */
412 public File(URI uri) {
413
414 // Check our many preconditions
415 if (!uri.isAbsolute())
416 throw new IllegalArgumentException("URI is not absolute");
417 if (uri.isOpaque())
418 throw new IllegalArgumentException("URI is not hierarchical");
419 String scheme = uri.getScheme();
420 if ((scheme == null) || !scheme.equalsIgnoreCase("file"))
421 throw new IllegalArgumentException("URI scheme is not \"file\"");
422 if (uri.getRawAuthority() != null)
423 throw new IllegalArgumentException("URI has an authority component");
424 if (uri.getRawFragment() != null)
425 throw new IllegalArgumentException("URI has a fragment component");
426 if (uri.getRawQuery() != null)
427 throw new IllegalArgumentException("URI has a query component");
428 String p = uri.getPath();
429 if (p.isEmpty())
430 throw new IllegalArgumentException("URI path component is empty");
431
432 // Okay, now initialize
433 p = fs.fromURIPath(p);
434 if (File.separatorChar != '/')
435 p = p.replace('/', File.separatorChar);
436 this.path = fs.normalize(p);
437 this.prefixLength = fs.prefixLength(this.path);
438 }
439
440
441 /* -- Path-component accessors -- */
442
443 /**
444 * Returns the name of the file or directory denoted by this abstract
445 * pathname. This is just the last name in the pathname's name
446 * sequence. If the pathname's name sequence is empty, then the empty
447 * string is returned.
448 *
449 * @return The name of the file or directory denoted by this abstract
450 * pathname, or the empty string if this pathname's name sequence
451 * is empty
452 */
453 public String getName() {
454 int index = path.lastIndexOf(separatorChar);
455 if (index < prefixLength) return path.substring(prefixLength);
456 return path.substring(index + 1);
457 }
458
459 /**
460 * Returns the pathname string of this abstract pathname's parent, or
461 * <code>null</code> if this pathname does not name a parent directory.
462 *
463 * <p> The <em>parent</em> of an abstract pathname consists of the
464 * pathname's prefix, if any, and each name in the pathname's name
465 * sequence except for the last. If the name sequence is empty then
466 * the pathname does not name a parent directory.
467 *
468 * @return The pathname string of the parent directory named by this
469 * abstract pathname, or <code>null</code> if this pathname
470 * does not name a parent
471 */
472 public String getParent() {
473 int index = path.lastIndexOf(separatorChar);
474 if (index < prefixLength) {
475 if ((prefixLength > 0) && (path.length() > prefixLength))
476 return path.substring(0, prefixLength);
477 return null;
478 }
479 return path.substring(0, index);
480 }
481
482 /**
483 * Returns the abstract pathname of this abstract pathname's parent,
484 * or <code>null</code> if this pathname does not name a parent
485 * directory.
486 *
487 * <p> The <em>parent</em> of an abstract pathname consists of the
488 * pathname's prefix, if any, and each name in the pathname's name
489 * sequence except for the last. If the name sequence is empty then
490 * the pathname does not name a parent directory.
491 *
492 * @return The abstract pathname of the parent directory named by this
493 * abstract pathname, or <code>null</code> if this pathname
494 * does not name a parent
495 *
496 * @since 1.2
497 */
498 public File getParentFile() {
499 String p = this.getParent();
500 if (p == null) return null;
501 return new File(p, this.prefixLength);
502 }
503
504 /**
505 * Converts this abstract pathname into a pathname string. The resulting
506 * string uses the {@link #separator default name-separator character} to
507 * separate the names in the name sequence.
508 *
509 * @return The string form of this abstract pathname
510 */
511 public String getPath() {
512 return path;
513 }
514
515
516 /* -- Path operations -- */
517
518 /**
519 * Tests whether this abstract pathname is absolute. The definition of
520 * absolute pathname is system dependent. On UNIX systems, a pathname is
521 * absolute if its prefix is <code>"/"</code>. On Microsoft Windows systems, a
522 * pathname is absolute if its prefix is a drive specifier followed by
523 * <code>"\\"</code>, or if its prefix is <code>"\\\\"</code>.
524 *
525 * @return <code>true</code> if this abstract pathname is absolute,
526 * <code>false</code> otherwise
527 */
528 public boolean isAbsolute() {
529 return fs.isAbsolute(this);
530 }
531
532 /**
533 * Returns the absolute pathname string of this abstract pathname.
534 *
535 * <p> If this abstract pathname is already absolute, then the pathname
536 * string is simply returned as if by the {@link #getPath}
537 * method. If this abstract pathname is the empty abstract pathname then
538 * the pathname string of the current user directory, which is named by the
539 * system property <code>user.dir</code>, is returned. Otherwise this
540 * pathname is resolved in a system-dependent way. On UNIX systems, a
541 * relative pathname is made absolute by resolving it against the current
542 * user directory. On Microsoft Windows systems, a relative pathname is made absolute
543 * by resolving it against the current directory of the drive named by the
544 * pathname, if any; if not, it is resolved against the current user
545 * directory.
546 *
547 * @return The absolute pathname string denoting the same file or
548 * directory as this abstract pathname
549 *
550 * @throws SecurityException
551 * If a required system property value cannot be accessed.
552 *
553 * @see java.io.File#isAbsolute()
554 */
555 public String getAbsolutePath() {
556 return fs.resolve(this);
557 }
558
559 /**
560 * Returns the absolute form of this abstract pathname. Equivalent to
561 * <code>new File(this.{@link #getAbsolutePath})</code>.
562 *
563 * @return The absolute abstract pathname denoting the same file or
564 * directory as this abstract pathname
565 *
566 * @throws SecurityException
567 * If a required system property value cannot be accessed.
568 *
569 * @since 1.2
570 */
571 public File getAbsoluteFile() {
572 String absPath = getAbsolutePath();
573 return new File(absPath, fs.prefixLength(absPath));
574 }
575
576 /**
577 * Returns the canonical pathname string of this abstract pathname.
578 *
579 * <p> A canonical pathname is both absolute and unique. The precise
580 * definition of canonical form is system-dependent. This method first
581 * converts this pathname to absolute form if necessary, as if by invoking the
582 * {@link #getAbsolutePath} method, and then maps it to its unique form in a
583 * system-dependent way. This typically involves removing redundant names
584 * such as {@code "."} and {@code ".."} from the pathname, resolving
585 * symbolic links (on UNIX platforms), and converting drive letters to a
586 * standard case (on Microsoft Windows platforms).
587 *
588 * <p> Every pathname that denotes an existing file or directory has a
589 * unique canonical form. Every pathname that denotes a nonexistent file
590 * or directory also has a unique canonical form. The canonical form of
591 * the pathname of a nonexistent file or directory may be different from
592 * the canonical form of the same pathname after the file or directory is
593 * created. Similarly, the canonical form of the pathname of an existing
594 * file or directory may be different from the canonical form of the same
595 * pathname after the file or directory is deleted.
596 *
597 * @return The canonical pathname string denoting the same file or
598 * directory as this abstract pathname
599 *
600 * @throws IOException
601 * If an I/O error occurs, which is possible because the
602 * construction of the canonical pathname may require
603 * filesystem queries
604 *
605 * @throws SecurityException
606 * If a required system property value cannot be accessed, or
607 * if a security manager exists and its {@link
608 * java.lang.SecurityManager#checkRead} method denies
609 * read access to the file
610 *
611 * @since 1.1
612 * @see Path#toRealPath
613 */
614 public String getCanonicalPath() throws IOException {
615 if (isInvalid()) {
616 throw new IOException("Invalid file path");
617 }
618 return fs.canonicalize(fs.resolve(this));
619 }
620
621 /**
622 * Returns the canonical form of this abstract pathname. Equivalent to
623 * <code>new File(this.{@link #getCanonicalPath})</code>.
624 *
625 * @return The canonical pathname string denoting the same file or
626 * directory as this abstract pathname
627 *
628 * @throws IOException
629 * If an I/O error occurs, which is possible because the
630 * construction of the canonical pathname may require
631 * filesystem queries
632 *
633 * @throws SecurityException
634 * If a required system property value cannot be accessed, or
635 * if a security manager exists and its {@link
636 * java.lang.SecurityManager#checkRead} method denies
637 * read access to the file
638 *
639 * @since 1.2
640 * @see Path#toRealPath
641 */
642 public File getCanonicalFile() throws IOException {
643 String canonPath = getCanonicalPath();
644 return new File(canonPath, fs.prefixLength(canonPath));
645 }
646
647 private static String slashify(String path, boolean isDirectory) {
648 String p = path;
649 if (File.separatorChar != '/')
650 p = p.replace(File.separatorChar, '/');
651 if (!p.startsWith("/"))
652 p = "/" + p;
653 if (!p.endsWith("/") && isDirectory)
654 p = p + "/";
655 return p;
656 }
657
658 /**
659 * Converts this abstract pathname into a <code>file:</code> URL. The
660 * exact form of the URL is system-dependent. If it can be determined that
661 * the file denoted by this abstract pathname is a directory, then the
662 * resulting URL will end with a slash.
663 *
664 * @return A URL object representing the equivalent file URL
665 *
666 * @throws MalformedURLException
667 * If the path cannot be parsed as a URL
668 *
669 * @see #toURI()
670 * @see java.net.URI
671 * @see java.net.URI#toURL()
672 * @see java.net.URL
673 * @since 1.2
674 *
675 * @deprecated This method does not automatically escape characters that
676 * are illegal in URLs. It is recommended that new code convert an
677 * abstract pathname into a URL by first converting it into a URI, via the
678 * {@link #toURI() toURI} method, and then converting the URI into a URL
679 * via the {@link java.net.URI#toURL() URI.toURL} method.
680 */
681 @Deprecated
682 public URL toURL() throws MalformedURLException {
683 if (isInvalid()) {
684 throw new MalformedURLException("Invalid file path");
685 }
686 return new URL("file", "", slashify(getAbsolutePath(), isDirectory()));
687 }
688
689 /**
690 * Constructs a {@code file:} URI that represents this abstract pathname.
691 *
692 * <p> The exact form of the URI is system-dependent. If it can be
693 * determined that the file denoted by this abstract pathname is a
694 * directory, then the resulting URI will end with a slash.
695 *
696 * <p> For a given abstract pathname <i>f</i>, it is guaranteed that
697 *
698 * <blockquote><code>
699 * new {@link #File(java.net.URI) File}(</code><i> f</i><code>.toURI()).equals(
700 * </code><i> f</i><code>.{@link #getAbsoluteFile() getAbsoluteFile}())
701 * </code></blockquote>
702 *
703 * so long as the original abstract pathname, the URI, and the new abstract
704 * pathname are all created in (possibly different invocations of) the same
705 * Java virtual machine. Due to the system-dependent nature of abstract
706 * pathnames, however, this relationship typically does not hold when a
707 * {@code file:} URI that is created in a virtual machine on one operating
708 * system is converted into an abstract pathname in a virtual machine on a
709 * different operating system.
710 *
711 * <p> Note that when this abstract pathname represents a UNC pathname then
712 * all components of the UNC (including the server name component) are encoded
713 * in the {@code URI} path. The authority component is undefined, meaning
714 * that it is represented as {@code null}. The {@link Path} class defines the
715 * {@link Path#toUri toUri} method to encode the server name in the authority
716 * component of the resulting {@code URI}. The {@link #toPath toPath} method
717 * may be used to obtain a {@code Path} representing this abstract pathname.
718 *
719 * @return An absolute, hierarchical URI with a scheme equal to
720 * {@code "file"}, a path representing this abstract pathname,
721 * and undefined authority, query, and fragment components
722 * @throws SecurityException If a required system property value cannot
723 * be accessed.
724 *
725 * @see #File(java.net.URI)
726 * @see java.net.URI
727 * @see java.net.URI#toURL()
728 * @since 1.4
729 */
730 public URI toURI() {
731 try {
732 File f = getAbsoluteFile();
733 String sp = slashify(f.getPath(), f.isDirectory());
734 if (sp.startsWith("//"))
735 sp = "//" + sp;
736 return new URI("file", null, sp, null);
737 } catch (URISyntaxException x) {
738 throw new Error(x); // Can't happen
739 }
740 }
741
742
743 /* -- Attribute accessors -- */
744
745 /**
746 * Tests whether the application can read the file denoted by this
747 * abstract pathname. On some platforms it may be possible to start the
748 * Java virtual machine with special privileges that allow it to read
749 * files that are marked as unreadable. Consequently this method may return
750 * {@code true} even though the file does not have read permissions.
751 *
752 * @return <code>true</code> if and only if the file specified by this
753 * abstract pathname exists <em>and</em> can be read by the
754 * application; <code>false</code> otherwise
755 *
756 * @throws SecurityException
757 * If a security manager exists and its {@link
758 * java.lang.SecurityManager#checkRead(java.lang.String)}
759 * method denies read access to the file
760 */
761 public boolean canRead() {
762 SecurityManager security = System.getSecurityManager();
763 if (security != null) {
764 security.checkRead(path);
765 }
766 if (isInvalid()) {
767 return false;
768 }
769 return fs.checkAccess(this, FileSystem.ACCESS_READ);
770 }
771
772 /**
773 * Tests whether the application can modify the file denoted by this
774 * abstract pathname. On some platforms it may be possible to start the
775 * Java virtual machine with special privileges that allow it to modify
776 * files that are marked read-only. Consequently this method may return
777 * {@code true} even though the file is marked read-only.
778 *
779 * @return <code>true</code> if and only if the file system actually
780 * contains a file denoted by this abstract pathname <em>and</em>
781 * the application is allowed to write to the file;
782 * <code>false</code> otherwise.
783 *
784 * @throws SecurityException
785 * If a security manager exists and its {@link
786 * java.lang.SecurityManager#checkWrite(java.lang.String)}
787 * method denies write access to the file
788 */
789 public boolean canWrite() {
790 SecurityManager security = System.getSecurityManager();
791 if (security != null) {
792 security.checkWrite(path);
793 }
794 if (isInvalid()) {
795 return false;
796 }
797 return fs.checkAccess(this, FileSystem.ACCESS_WRITE);
798 }
799
800 /**
801 * Tests whether the file or directory denoted by this abstract pathname
802 * exists.
803 *
804 * @return <code>true</code> if and only if the file or directory denoted
805 * by this abstract pathname exists; <code>false</code> otherwise
806 *
807 * @throws SecurityException
808 * If a security manager exists and its {@link
809 * java.lang.SecurityManager#checkRead(java.lang.String)}
810 * method denies read access to the file or directory
811 */
812 public boolean exists() {
813 SecurityManager security = System.getSecurityManager();
814 if (security != null) {
815 security.checkRead(path);
816 }
817 if (isInvalid()) {
818 return false;
819 }
820 return ((fs.getBooleanAttributes(this) & FileSystem.BA_EXISTS) != 0);
821 }
822
823 /**
824 * Tests whether the file denoted by this abstract pathname is a
825 * directory.
826 *
827 * <p> Where it is required to distinguish an I/O exception from the case
828 * that the file is not a directory, or where several attributes of the
829 * same file are required at the same time, then the {@link
830 * java.nio.file.Files#readAttributes(Path,Class,LinkOption[])
831 * Files.readAttributes} method may be used.
832 *
833 * @return <code>true</code> if and only if the file denoted by this
834 * abstract pathname exists <em>and</em> is a directory;
835 * <code>false</code> otherwise
836 *
837 * @throws SecurityException
838 * If a security manager exists and its {@link
839 * java.lang.SecurityManager#checkRead(java.lang.String)}
840 * method denies read access to the file
841 */
842 public boolean isDirectory() {
843 SecurityManager security = System.getSecurityManager();
844 if (security != null) {
845 security.checkRead(path);
846 }
847 if (isInvalid()) {
848 return false;
849 }
850 return ((fs.getBooleanAttributes(this) & FileSystem.BA_DIRECTORY)
851 != 0);
852 }
853
854 /**
855 * Tests whether the file denoted by this abstract pathname is a normal
856 * file. A file is <em>normal</em> if it is not a directory and, in
857 * addition, satisfies other system-dependent criteria. Any non-directory
858 * file created by a Java application is guaranteed to be a normal file.
859 *
860 * <p> Where it is required to distinguish an I/O exception from the case
861 * that the file is not a normal file, or where several attributes of the
862 * same file are required at the same time, then the {@link
863 * java.nio.file.Files#readAttributes(Path,Class,LinkOption[])
864 * Files.readAttributes} method may be used.
865 *
866 * @return <code>true</code> if and only if the file denoted by this
867 * abstract pathname exists <em>and</em> is a normal file;
868 * <code>false</code> otherwise
869 *
870 * @throws SecurityException
871 * If a security manager exists and its {@link
872 * java.lang.SecurityManager#checkRead(java.lang.String)}
873 * method denies read access to the file
874 */
875 public boolean isFile() {
876 SecurityManager security = System.getSecurityManager();
877 if (security != null) {
878 security.checkRead(path);
879 }
880 if (isInvalid()) {
881 return false;
882 }
883 return ((fs.getBooleanAttributes(this) & FileSystem.BA_REGULAR) != 0);
884 }
885
886 /**
887 * Tests whether the file named by this abstract pathname is a hidden
888 * file. The exact definition of <em>hidden</em> is system-dependent. On
889 * UNIX systems, a file is considered to be hidden if its name begins with
890 * a period character (<code>'.'</code>). On Microsoft Windows systems, a file is
891 * considered to be hidden if it has been marked as such in the filesystem.
892 *
893 * @return <code>true</code> if and only if the file denoted by this
894 * abstract pathname is hidden according to the conventions of the
895 * underlying platform
896 *
897 * @throws SecurityException
898 * If a security manager exists and its {@link
899 * java.lang.SecurityManager#checkRead(java.lang.String)}
900 * method denies read access to the file
901 *
902 * @since 1.2
903 */
904 public boolean isHidden() {
905 SecurityManager security = System.getSecurityManager();
906 if (security != null) {
907 security.checkRead(path);
908 }
909 if (isInvalid()) {
910 return false;
911 }
912 return ((fs.getBooleanAttributes(this) & FileSystem.BA_HIDDEN) != 0);
913 }
914
915 /**
916 * Returns the time that the file denoted by this abstract pathname was
917 * last modified.
918 *
919 * @apiNote
920 * While the unit of time of the return value is milliseconds, the
921 * granularity of the value depends on the underlying file system and may
922 * be larger. For example, some file systems use time stamps in units of
923 * seconds.
924 *
925 * <p> Where it is required to distinguish an I/O exception from the case
926 * where {@code 0L} is returned, or where several attributes of the
927 * same file are required at the same time, or where the time of last
928 * access or the creation time are required, then the {@link
929 * java.nio.file.Files#readAttributes(Path,Class,LinkOption[])
930 * Files.readAttributes} method may be used. If however only the
931 * time of last modification is required, then the
932 * {@link java.nio.file.Files#getLastModifiedTime(Path,LinkOption[])
933 * Files.getLastModifiedTime} method may be used instead.
934 *
935 * @return A <code>long</code> value representing the time the file was
936 * last modified, measured in milliseconds since the epoch
937 * (00:00:00 GMT, January 1, 1970), or <code>0L</code> if the
938 * file does not exist or if an I/O error occurs. The value may
939 * be negative indicating the number of milliseconds before the
940 * epoch
941 *
942 * @throws SecurityException
943 * If a security manager exists and its {@link
944 * java.lang.SecurityManager#checkRead(java.lang.String)}
945 * method denies read access to the file
946 */
947 public long lastModified() {
948 SecurityManager security = System.getSecurityManager();
949 if (security != null) {
950 security.checkRead(path);
951 }
952 if (isInvalid()) {
953 return 0L;
954 }
955 return fs.getLastModifiedTime(this);
956 }
957
958 /**
959 * Returns the length of the file denoted by this abstract pathname.
960 * The return value is unspecified if this pathname denotes a directory.
961 *
962 * <p> Where it is required to distinguish an I/O exception from the case
963 * that {@code 0L} is returned, or where several attributes of the same file
964 * are required at the same time, then the {@link
965 * java.nio.file.Files#readAttributes(Path,Class,LinkOption[])
966 * Files.readAttributes} method may be used.
967 *
968 * @return The length, in bytes, of the file denoted by this abstract
969 * pathname, or <code>0L</code> if the file does not exist. Some
970 * operating systems may return <code>0L</code> for pathnames
971 * denoting system-dependent entities such as devices or pipes.
972 *
973 * @throws SecurityException
974 * If a security manager exists and its {@link
975 * java.lang.SecurityManager#checkRead(java.lang.String)}
976 * method denies read access to the file
977 */
978 public long length() {
979 SecurityManager security = System.getSecurityManager();
980 if (security != null) {
981 security.checkRead(path);
982 }
983 if (isInvalid()) {
984 return 0L;
985 }
986 return fs.getLength(this);
987 }
988
989
990 /* -- File operations -- */
991
992 /**
993 * Atomically creates a new, empty file named by this abstract pathname if
994 * and only if a file with this name does not yet exist. The check for the
995 * existence of the file and the creation of the file if it does not exist
996 * are a single operation that is atomic with respect to all other
997 * filesystem activities that might affect the file.
998 * <P>
999 * Note: this method should <i>not</i> be used for file-locking, as
1000 * the resulting protocol cannot be made to work reliably. The
1001 * {@link java.nio.channels.FileLock FileLock}
1002 * facility should be used instead.
1003 *
1004 * @return <code>true</code> if the named file does not exist and was
1005 * successfully created; <code>false</code> if the named file
1006 * already exists
1007 *
1008 * @throws IOException
1009 * If an I/O error occurred
1010 *
1011 * @throws SecurityException
1012 * If a security manager exists and its {@link
1013 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1014 * method denies write access to the file
1015 *
1016 * @since 1.2
1017 */
1018 public boolean createNewFile() throws IOException {
1019 SecurityManager security = System.getSecurityManager();
1020 if (security != null) security.checkWrite(path);
1021 if (isInvalid()) {
1022 throw new IOException("Invalid file path");
1023 }
1024 return fs.createFileExclusively(path);
1025 }
1026
1027 /**
1028 * Deletes the file or directory denoted by this abstract pathname. If
1029 * this pathname denotes a directory, then the directory must be empty in
1030 * order to be deleted.
1031 *
1032 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1033 * java.nio.file.Files#delete(Path) delete} method to throw an {@link IOException}
1034 * when a file cannot be deleted. This is useful for error reporting and to
1035 * diagnose why a file cannot be deleted.
1036 *
1037 * @return <code>true</code> if and only if the file or directory is
1038 * successfully deleted; <code>false</code> otherwise
1039 *
1040 * @throws SecurityException
1041 * If a security manager exists and its {@link
1042 * java.lang.SecurityManager#checkDelete} method denies
1043 * delete access to the file
1044 */
1045 public boolean delete() {
1046 SecurityManager security = System.getSecurityManager();
1047 if (security != null) {
1048 security.checkDelete(path);
1049 }
1050 if (isInvalid()) {
1051 return false;
1052 }
1053 return fs.delete(this);
1054 }
1055
1056 /**
1057 * Requests that the file or directory denoted by this abstract
1058 * pathname be deleted when the virtual machine terminates.
1059 * Files (or directories) are deleted in the reverse order that
1060 * they are registered. Invoking this method to delete a file or
1061 * directory that is already registered for deletion has no effect.
1062 * Deletion will be attempted only for normal termination of the
1063 * virtual machine, as defined by the Java Language Specification.
1064 *
1065 * <p>
1066 * Once deletion has been requested, it may be cancelled by invoking
1067 * {@link #cancelDeleteOnExit()}.
1068 *
1069 * <P>
1070 * Note: this method should <i>not</i> be used for file-locking, as
1071 * the resulting protocol cannot be made to work reliably. The
1072 * {@link java.nio.channels.FileLock FileLock}
1073 * facility should be used instead.
1074 *
1075 * @throws SecurityException
1076 * If a security manager exists and its {@link
1077 * java.lang.SecurityManager#checkDelete} method denies
1078 * delete access to the file
1079 *
1080 * @see #cancelDeleteOnExit
1081 * @see #delete
1082 *
1083 * @since 1.2
1084 */
1085 public void deleteOnExit() {
1086 SecurityManager security = System.getSecurityManager();
1087 if (security != null) {
1088 security.checkDelete(path);
1089 }
1090 if (isInvalid()) {
1091 return;
1092 }
1093 DeleteOnExitHook.add(path);
1094 }
1095
1096 /**
1097 * Cancels any request that the file or directory denoted by this
1098 * abstract pathname be deleted when the virtual machine terminates.
1099 * Invoking this method for a file or directory that is not already
1100 * registered for deletion has no effect. If a file or directory is
1101 * registered for deletion but is explicitly deleted before normal
1102 * termination of the virtual machine, then it is recommended to call
1103 * this method to free resources used to track the file for deletion.
1104 *
1105 * @see #deleteOnExit
1106 *
1107 * @since 14
1108 */
1109 public void cancelDeleteOnExit() {
1110 if (isInvalid()) {
1111 return;
1112 }
1113 DeleteOnExitHook.remove(path);
1114 }
1115
1116 /**
1117 * Returns an array of strings naming the files and directories in the
1118 * directory denoted by this abstract pathname.
1119 *
1120 * <p> If this abstract pathname does not denote a directory, then this
1121 * method returns {@code null}. Otherwise an array of strings is
1122 * returned, one for each file or directory in the directory. Names
1123 * denoting the directory itself and the directory's parent directory are
1124 * not included in the result. Each string is a file name rather than a
1125 * complete path.
1126 *
1127 * <p> There is no guarantee that the name strings in the resulting array
1128 * will appear in any specific order; they are not, in particular,
1129 * guaranteed to appear in alphabetical order.
1130 *
1131 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1132 * java.nio.file.Files#newDirectoryStream(Path) newDirectoryStream} method to
1133 * open a directory and iterate over the names of the files in the directory.
1134 * This may use less resources when working with very large directories, and
1135 * may be more responsive when working with remote directories.
1136 *
1137 * @return An array of strings naming the files and directories in the
1138 * directory denoted by this abstract pathname. The array will be
1139 * empty if the directory is empty. Returns {@code null} if
1140 * this abstract pathname does not denote a directory, or if an
1141 * I/O error occurs.
1142 *
1143 * @throws SecurityException
1144 * If a security manager exists and its {@link
1145 * SecurityManager#checkRead(String)} method denies read access to
1146 * the directory
1147 */
1148 public String[] list() {
1149 SecurityManager security = System.getSecurityManager();
1150 if (security != null) {
1151 security.checkRead(path);
1152 }
1153 if (isInvalid()) {
1154 return null;
1155 }
1156 return fs.list(this);
1157 }
1158
1159 /**
1160 * Returns an array of strings naming the files and directories in the
1161 * directory denoted by this abstract pathname that satisfy the specified
1162 * filter. The behavior of this method is the same as that of the
1163 * {@link #list()} method, except that the strings in the returned array
1164 * must satisfy the filter. If the given {@code filter} is {@code null}
1165 * then all names are accepted. Otherwise, a name satisfies the filter if
1166 * and only if the value {@code true} results when the {@link
1167 * FilenameFilter#accept FilenameFilter.accept(File, String)} method
1168 * of the filter is invoked on this abstract pathname and the name of a
1169 * file or directory in the directory that it denotes.
1170 *
1171 * @param filter
1172 * A filename filter
1173 *
1174 * @return An array of strings naming the files and directories in the
1175 * directory denoted by this abstract pathname that were accepted
1176 * by the given {@code filter}. The array will be empty if the
1177 * directory is empty or if no names were accepted by the filter.
1178 * Returns {@code null} if this abstract pathname does not denote
1179 * a directory, or if an I/O error occurs.
1180 *
1181 * @throws SecurityException
1182 * If a security manager exists and its {@link
1183 * SecurityManager#checkRead(String)} method denies read access to
1184 * the directory
1185 *
1186 * @see java.nio.file.Files#newDirectoryStream(Path,String)
1187 */
1188 public String[] list(FilenameFilter filter) {
1189 String names[] = list();
1190 if ((names == null) || (filter == null)) {
1191 return names;
1192 }
1193 List<String> v = new ArrayList<>();
1194 for (int i = 0 ; i < names.length ; i++) {
1195 if (filter.accept(this, names[i])) {
1196 v.add(names[i]);
1197 }
1198 }
1199 return v.toArray(new String[v.size()]);
1200 }
1201
1202 /**
1203 * Returns an array of abstract pathnames denoting the files in the
1204 * directory denoted by this abstract pathname.
1205 *
1206 * <p> If this abstract pathname does not denote a directory, then this
1207 * method returns {@code null}. Otherwise an array of {@code File} objects
1208 * is returned, one for each file or directory in the directory. Pathnames
1209 * denoting the directory itself and the directory's parent directory are
1210 * not included in the result. Each resulting abstract pathname is
1211 * constructed from this abstract pathname using the {@link #File(File,
1212 * String) File(File, String)} constructor. Therefore if this
1213 * pathname is absolute then each resulting pathname is absolute; if this
1214 * pathname is relative then each resulting pathname will be relative to
1215 * the same directory.
1216 *
1217 * <p> There is no guarantee that the name strings in the resulting array
1218 * will appear in any specific order; they are not, in particular,
1219 * guaranteed to appear in alphabetical order.
1220 *
1221 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1222 * java.nio.file.Files#newDirectoryStream(Path) newDirectoryStream} method
1223 * to open a directory and iterate over the names of the files in the
1224 * directory. This may use less resources when working with very large
1225 * directories.
1226 *
1227 * @return An array of abstract pathnames denoting the files and
1228 * directories in the directory denoted by this abstract pathname.
1229 * The array will be empty if the directory is empty. Returns
1230 * {@code null} if this abstract pathname does not denote a
1231 * directory, or if an I/O error occurs.
1232 *
1233 * @throws SecurityException
1234 * If a security manager exists and its {@link
1235 * SecurityManager#checkRead(String)} method denies read access to
1236 * the directory
1237 *
1238 * @since 1.2
1239 */
1240 public File[] listFiles() {
1241 String[] ss = list();
1242 if (ss == null) return null;
1243 int n = ss.length;
1244 File[] fs = new File[n];
1245 for (int i = 0; i < n; i++) {
1246 fs[i] = new File(ss[i], this);
1247 }
1248 return fs;
1249 }
1250
1251 /**
1252 * Returns an array of abstract pathnames denoting the files and
1253 * directories in the directory denoted by this abstract pathname that
1254 * satisfy the specified filter. The behavior of this method is the same
1255 * as that of the {@link #listFiles()} method, except that the pathnames in
1256 * the returned array must satisfy the filter. If the given {@code filter}
1257 * is {@code null} then all pathnames are accepted. Otherwise, a pathname
1258 * satisfies the filter if and only if the value {@code true} results when
1259 * the {@link FilenameFilter#accept
1260 * FilenameFilter.accept(File, String)} method of the filter is
1261 * invoked on this abstract pathname and the name of a file or directory in
1262 * the directory that it denotes.
1263 *
1264 * @param filter
1265 * A filename filter
1266 *
1267 * @return An array of abstract pathnames denoting the files and
1268 * directories in the directory denoted by this abstract pathname.
1269 * The array will be empty if the directory is empty. Returns
1270 * {@code null} if this abstract pathname does not denote a
1271 * directory, or if an I/O error occurs.
1272 *
1273 * @throws SecurityException
1274 * If a security manager exists and its {@link
1275 * SecurityManager#checkRead(String)} method denies read access to
1276 * the directory
1277 *
1278 * @since 1.2
1279 * @see java.nio.file.Files#newDirectoryStream(Path,String)
1280 */
1281 public File[] listFiles(FilenameFilter filter) {
1282 String ss[] = list();
1283 if (ss == null) return null;
1284 ArrayList<File> files = new ArrayList<>();
1285 for (String s : ss)
1286 if ((filter == null) || filter.accept(this, s))
1287 files.add(new File(s, this));
1288 return files.toArray(new File[files.size()]);
1289 }
1290
1291 /**
1292 * Returns an array of abstract pathnames denoting the files and
1293 * directories in the directory denoted by this abstract pathname that
1294 * satisfy the specified filter. The behavior of this method is the same
1295 * as that of the {@link #listFiles()} method, except that the pathnames in
1296 * the returned array must satisfy the filter. If the given {@code filter}
1297 * is {@code null} then all pathnames are accepted. Otherwise, a pathname
1298 * satisfies the filter if and only if the value {@code true} results when
1299 * the {@link FileFilter#accept FileFilter.accept(File)} method of the
1300 * filter is invoked on the pathname.
1301 *
1302 * @param filter
1303 * A file filter
1304 *
1305 * @return An array of abstract pathnames denoting the files and
1306 * directories in the directory denoted by this abstract pathname.
1307 * The array will be empty if the directory is empty. Returns
1308 * {@code null} if this abstract pathname does not denote a
1309 * directory, or if an I/O error occurs.
1310 *
1311 * @throws SecurityException
1312 * If a security manager exists and its {@link
1313 * SecurityManager#checkRead(String)} method denies read access to
1314 * the directory
1315 *
1316 * @since 1.2
1317 * @see java.nio.file.Files#newDirectoryStream(Path,java.nio.file.DirectoryStream.Filter)
1318 */
1319 public File[] listFiles(FileFilter filter) {
1320 String ss[] = list();
1321 if (ss == null) return null;
1322 ArrayList<File> files = new ArrayList<>();
1323 for (String s : ss) {
1324 File f = new File(s, this);
1325 if ((filter == null) || filter.accept(f))
1326 files.add(f);
1327 }
1328 return files.toArray(new File[files.size()]);
1329 }
1330
1331 /**
1332 * Creates the directory named by this abstract pathname.
1333 *
1334 * @return <code>true</code> if and only if the directory was
1335 * created; <code>false</code> otherwise
1336 *
1337 * @throws SecurityException
1338 * If a security manager exists and its {@link
1339 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1340 * method does not permit the named directory to be created
1341 */
1342 public boolean mkdir() {
1343 SecurityManager security = System.getSecurityManager();
1344 if (security != null) {
1345 security.checkWrite(path);
1346 }
1347 if (isInvalid()) {
1348 return false;
1349 }
1350 return fs.createDirectory(this);
1351 }
1352
1353 /**
1354 * Creates the directory named by this abstract pathname, including any
1355 * necessary but nonexistent parent directories. Note that if this
1356 * operation fails it may have succeeded in creating some of the necessary
1357 * parent directories.
1358 *
1359 * @return <code>true</code> if and only if the directory was created,
1360 * along with all necessary parent directories; <code>false</code>
1361 * otherwise
1362 *
1363 * @throws SecurityException
1364 * If a security manager exists and its {@link
1365 * java.lang.SecurityManager#checkRead(java.lang.String)}
1366 * method does not permit verification of the existence of the
1367 * named directory and all necessary parent directories; or if
1368 * the {@link
1369 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1370 * method does not permit the named directory and all necessary
1371 * parent directories to be created
1372 */
1373 public boolean mkdirs() {
1374 if (exists()) {
1375 return false;
1376 }
1377 if (mkdir()) {
1378 return true;
1379 }
1380 File canonFile = null;
1381 try {
1382 canonFile = getCanonicalFile();
1383 } catch (IOException e) {
1384 return false;
1385 }
1386
1387 File parent = canonFile.getParentFile();
1388 return (parent != null && (parent.mkdirs() || parent.exists()) &&
1389 canonFile.mkdir());
1390 }
1391
1392 /**
1393 * Renames the file denoted by this abstract pathname.
1394 *
1395 * <p> Many aspects of the behavior of this method are inherently
1396 * platform-dependent: The rename operation might not be able to move a
1397 * file from one filesystem to another, it might not be atomic, and it
1398 * might not succeed if a file with the destination abstract pathname
1399 * already exists. The return value should always be checked to make sure
1400 * that the rename operation was successful.
1401 *
1402 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1403 * java.nio.file.Files#move move} method to move or rename a file in a
1404 * platform independent manner.
1405 *
1406 * @param dest The new abstract pathname for the named file
1407 *
1408 * @return <code>true</code> if and only if the renaming succeeded;
1409 * <code>false</code> otherwise
1410 *
1411 * @throws SecurityException
1412 * If a security manager exists and its {@link
1413 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1414 * method denies write access to either the old or new pathnames
1415 *
1416 * @throws NullPointerException
1417 * If parameter <code>dest</code> is <code>null</code>
1418 */
1419 public boolean renameTo(File dest) {
1420 if (dest == null) {
1421 throw new NullPointerException();
1422 }
1423 SecurityManager security = System.getSecurityManager();
1424 if (security != null) {
1425 security.checkWrite(path);
1426 security.checkWrite(dest.path);
1427 }
1428 if (this.isInvalid() || dest.isInvalid()) {
1429 return false;
1430 }
1431 return fs.rename(this, dest);
1432 }
1433
1434 /**
1435 * Sets the last-modified time of the file or directory named by this
1436 * abstract pathname.
1437 *
1438 * <p> All platforms support file-modification times to the nearest second,
1439 * but some provide more precision. The argument will be truncated to fit
1440 * the supported precision. If the operation succeeds and no intervening
1441 * operations on the file take place, then the next invocation of the
1442 * {@link #lastModified} method will return the (possibly
1443 * truncated) <code>time</code> argument that was passed to this method.
1444 *
1445 * @param time The new last-modified time, measured in milliseconds since
1446 * the epoch (00:00:00 GMT, January 1, 1970)
1447 *
1448 * @return <code>true</code> if and only if the operation succeeded;
1449 * <code>false</code> otherwise
1450 *
1451 * @throws IllegalArgumentException If the argument is negative
1452 *
1453 * @throws SecurityException
1454 * If a security manager exists and its {@link
1455 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1456 * method denies write access to the named file
1457 *
1458 * @since 1.2
1459 */
1460 public boolean setLastModified(long time) {
1461 if (time < 0) throw new IllegalArgumentException("Negative time");
1462 SecurityManager security = System.getSecurityManager();
1463 if (security != null) {
1464 security.checkWrite(path);
1465 }
1466 if (isInvalid()) {
1467 return false;
1468 }
1469 return fs.setLastModifiedTime(this, time);
1470 }
1471
1472 /**
1473 * Marks the file or directory named by this abstract pathname so that
1474 * only read operations are allowed. After invoking this method the file
1475 * or directory will not change until it is either deleted or marked
1476 * to allow write access. On some platforms it may be possible to start the
1477 * Java virtual machine with special privileges that allow it to modify
1478 * files that are marked read-only. Whether or not a read-only file or
1479 * directory may be deleted depends upon the underlying system.
1480 *
1481 * @return <code>true</code> if and only if the operation succeeded;
1482 * <code>false</code> otherwise
1483 *
1484 * @throws SecurityException
1485 * If a security manager exists and its {@link
1486 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1487 * method denies write access to the named file
1488 *
1489 * @since 1.2
1490 */
1491 public boolean setReadOnly() {
1492 SecurityManager security = System.getSecurityManager();
1493 if (security != null) {
1494 security.checkWrite(path);
1495 }
1496 if (isInvalid()) {
1497 return false;
1498 }
1499 return fs.setReadOnly(this);
1500 }
1501
1502 /**
1503 * Sets the owner's or everybody's write permission for this abstract
1504 * pathname. On some platforms it may be possible to start the Java virtual
1505 * machine with special privileges that allow it to modify files that
1506 * disallow write operations.
1507 *
1508 * <p> The {@link java.nio.file.Files} class defines methods that operate on
1509 * file attributes including file permissions. This may be used when finer
1510 * manipulation of file permissions is required.
1511 *
1512 * @param writable
1513 * If <code>true</code>, sets the access permission to allow write
1514 * operations; if <code>false</code> to disallow write operations
1515 *
1516 * @param ownerOnly
1517 * If <code>true</code>, the write permission applies only to the
1518 * owner's write permission; otherwise, it applies to everybody. If
1519 * the underlying file system can not distinguish the owner's write
1520 * permission from that of others, then the permission will apply to
1521 * everybody, regardless of this value.
1522 *
1523 * @return <code>true</code> if and only if the operation succeeded. The
1524 * operation will fail if the user does not have permission to change
1525 * the access permissions of this abstract pathname.
1526 *
1527 * @throws SecurityException
1528 * If a security manager exists and its {@link
1529 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1530 * method denies write access to the named file
1531 *
1532 * @since 1.6
1533 */
1534 public boolean setWritable(boolean writable, boolean ownerOnly) {
1535 SecurityManager security = System.getSecurityManager();
1536 if (security != null) {
1537 security.checkWrite(path);
1538 }
1539 if (isInvalid()) {
1540 return false;
1541 }
1542 return fs.setPermission(this, FileSystem.ACCESS_WRITE, writable, ownerOnly);
1543 }
1544
1545 /**
1546 * A convenience method to set the owner's write permission for this abstract
1547 * pathname. On some platforms it may be possible to start the Java virtual
1548 * machine with special privileges that allow it to modify files that
1549 * disallow write operations.
1550 *
1551 * <p> An invocation of this method of the form {@code file.setWritable(arg)}
1552 * behaves in exactly the same way as the invocation
1553 *
1554 * <pre>{@code
1555 * file.setWritable(arg, true)
1556 * }</pre>
1557 *
1558 * @param writable
1559 * If <code>true</code>, sets the access permission to allow write
1560 * operations; if <code>false</code> to disallow write operations
1561 *
1562 * @return <code>true</code> if and only if the operation succeeded. The
1563 * operation will fail if the user does not have permission to
1564 * change the access permissions of this abstract pathname.
1565 *
1566 * @throws SecurityException
1567 * If a security manager exists and its {@link
1568 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1569 * method denies write access to the file
1570 *
1571 * @since 1.6
1572 */
1573 public boolean setWritable(boolean writable) {
1574 return setWritable(writable, true);
1575 }
1576
1577 /**
1578 * Sets the owner's or everybody's read permission for this abstract
1579 * pathname. On some platforms it may be possible to start the Java virtual
1580 * machine with special privileges that allow it to read files that are
1581 * marked as unreadable.
1582 *
1583 * <p> The {@link java.nio.file.Files} class defines methods that operate on
1584 * file attributes including file permissions. This may be used when finer
1585 * manipulation of file permissions is required.
1586 *
1587 * @param readable
1588 * If <code>true</code>, sets the access permission to allow read
1589 * operations; if <code>false</code> to disallow read operations
1590 *
1591 * @param ownerOnly
1592 * If <code>true</code>, the read permission applies only to the
1593 * owner's read permission; otherwise, it applies to everybody. If
1594 * the underlying file system can not distinguish the owner's read
1595 * permission from that of others, then the permission will apply to
1596 * everybody, regardless of this value.
1597 *
1598 * @return <code>true</code> if and only if the operation succeeded. The
1599 * operation will fail if the user does not have permission to
1600 * change the access permissions of this abstract pathname. If
1601 * <code>readable</code> is <code>false</code> and the underlying
1602 * file system does not implement a read permission, then the
1603 * operation will fail.
1604 *
1605 * @throws SecurityException
1606 * If a security manager exists and its {@link
1607 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1608 * method denies write access to the file
1609 *
1610 * @since 1.6
1611 */
1612 public boolean setReadable(boolean readable, boolean ownerOnly) {
1613 SecurityManager security = System.getSecurityManager();
1614 if (security != null) {
1615 security.checkWrite(path);
1616 }
1617 if (isInvalid()) {
1618 return false;
1619 }
1620 return fs.setPermission(this, FileSystem.ACCESS_READ, readable, ownerOnly);
1621 }
1622
1623 /**
1624 * A convenience method to set the owner's read permission for this abstract
1625 * pathname. On some platforms it may be possible to start the Java virtual
1626 * machine with special privileges that allow it to read files that are
1627 * marked as unreadable.
1628 *
1629 * <p>An invocation of this method of the form {@code file.setReadable(arg)}
1630 * behaves in exactly the same way as the invocation
1631 *
1632 * <pre>{@code
1633 * file.setReadable(arg, true)
1634 * }</pre>
1635 *
1636 * @param readable
1637 * If <code>true</code>, sets the access permission to allow read
1638 * operations; if <code>false</code> to disallow read operations
1639 *
1640 * @return <code>true</code> if and only if the operation succeeded. The
1641 * operation will fail if the user does not have permission to
1642 * change the access permissions of this abstract pathname. If
1643 * <code>readable</code> is <code>false</code> and the underlying
1644 * file system does not implement a read permission, then the
1645 * operation will fail.
1646 *
1647 * @throws SecurityException
1648 * If a security manager exists and its {@link
1649 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1650 * method denies write access to the file
1651 *
1652 * @since 1.6
1653 */
1654 public boolean setReadable(boolean readable) {
1655 return setReadable(readable, true);
1656 }
1657
1658 /**
1659 * Sets the owner's or everybody's execute permission for this abstract
1660 * pathname. On some platforms it may be possible to start the Java virtual
1661 * machine with special privileges that allow it to execute files that are
1662 * not marked executable.
1663 *
1664 * <p> The {@link java.nio.file.Files} class defines methods that operate on
1665 * file attributes including file permissions. This may be used when finer
1666 * manipulation of file permissions is required.
1667 *
1668 * @param executable
1669 * If <code>true</code>, sets the access permission to allow execute
1670 * operations; if <code>false</code> to disallow execute operations
1671 *
1672 * @param ownerOnly
1673 * If <code>true</code>, the execute permission applies only to the
1674 * owner's execute permission; otherwise, it applies to everybody.
1675 * If the underlying file system can not distinguish the owner's
1676 * execute permission from that of others, then the permission will
1677 * apply to everybody, regardless of this value.
1678 *
1679 * @return <code>true</code> if and only if the operation succeeded. The
1680 * operation will fail if the user does not have permission to
1681 * change the access permissions of this abstract pathname. If
1682 * <code>executable</code> is <code>false</code> and the underlying
1683 * file system does not implement an execute permission, then the
1684 * operation will fail.
1685 *
1686 * @throws SecurityException
1687 * If a security manager exists and its {@link
1688 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1689 * method denies write access to the file
1690 *
1691 * @since 1.6
1692 */
1693 public boolean setExecutable(boolean executable, boolean ownerOnly) {
1694 SecurityManager security = System.getSecurityManager();
1695 if (security != null) {
1696 security.checkWrite(path);
1697 }
1698 if (isInvalid()) {
1699 return false;
1700 }
1701 return fs.setPermission(this, FileSystem.ACCESS_EXECUTE, executable, ownerOnly);
1702 }
1703
1704 /**
1705 * A convenience method to set the owner's execute permission for this
1706 * abstract pathname. On some platforms it may be possible to start the Java
1707 * virtual machine with special privileges that allow it to execute files
1708 * that are not marked executable.
1709 *
1710 * <p>An invocation of this method of the form {@code file.setExcutable(arg)}
1711 * behaves in exactly the same way as the invocation
1712 *
1713 * <pre>{@code
1714 * file.setExecutable(arg, true)
1715 * }</pre>
1716 *
1717 * @param executable
1718 * If <code>true</code>, sets the access permission to allow execute
1719 * operations; if <code>false</code> to disallow execute operations
1720 *
1721 * @return <code>true</code> if and only if the operation succeeded. The
1722 * operation will fail if the user does not have permission to
1723 * change the access permissions of this abstract pathname. If
1724 * <code>executable</code> is <code>false</code> and the underlying
1725 * file system does not implement an execute permission, then the
1726 * operation will fail.
1727 *
1728 * @throws SecurityException
1729 * If a security manager exists and its {@link
1730 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1731 * method denies write access to the file
1732 *
1733 * @since 1.6
1734 */
1735 public boolean setExecutable(boolean executable) {
1736 return setExecutable(executable, true);
1737 }
1738
1739 /**
1740 * Tests whether the application can execute the file denoted by this
1741 * abstract pathname. On some platforms it may be possible to start the
1742 * Java virtual machine with special privileges that allow it to execute
1743 * files that are not marked executable. Consequently this method may return
1744 * {@code true} even though the file does not have execute permissions.
1745 *
1746 * @return <code>true</code> if and only if the abstract pathname exists
1747 * <em>and</em> the application is allowed to execute the file
1748 *
1749 * @throws SecurityException
1750 * If a security manager exists and its {@link
1751 * java.lang.SecurityManager#checkExec(java.lang.String)}
1752 * method denies execute access to the file
1753 *
1754 * @since 1.6
1755 */
1756 public boolean canExecute() {
1757 SecurityManager security = System.getSecurityManager();
1758 if (security != null) {
1759 security.checkExec(path);
1760 }
1761 if (isInvalid()) {
1762 return false;
1763 }
1764 return fs.checkAccess(this, FileSystem.ACCESS_EXECUTE);
1765 }
1766
1767
1768 /* -- Filesystem interface -- */
1769
1770 /**
1771 * List the available filesystem roots.
1772 *
1773 * <p> A particular Java platform may support zero or more
1774 * hierarchically-organized file systems. Each file system has a
1775 * {@code root} directory from which all other files in that file system
1776 * can be reached. Windows platforms, for example, have a root directory
1777 * for each active drive; UNIX platforms have a single root directory,
1778 * namely {@code "/"}. The set of available filesystem roots is affected
1779 * by various system-level operations such as the insertion or ejection of
1780 * removable media and the disconnecting or unmounting of physical or
1781 * virtual disk drives.
1782 *
1783 * <p> This method returns an array of {@code File} objects that denote the
1784 * root directories of the available filesystem roots. It is guaranteed
1785 * that the canonical pathname of any file physically present on the local
1786 * machine will begin with one of the roots returned by this method.
1787 *
1788 * <p> The canonical pathname of a file that resides on some other machine
1789 * and is accessed via a remote-filesystem protocol such as SMB or NFS may
1790 * or may not begin with one of the roots returned by this method. If the
1791 * pathname of a remote file is syntactically indistinguishable from the
1792 * pathname of a local file then it will begin with one of the roots
1793 * returned by this method. Thus, for example, {@code File} objects
1794 * denoting the root directories of the mapped network drives of a Windows
1795 * platform will be returned by this method, while {@code File} objects
1796 * containing UNC pathnames will not be returned by this method.
1797 *
1798 * <p> Unlike most methods in this class, this method does not throw
1799 * security exceptions. If a security manager exists and its {@link
1800 * SecurityManager#checkRead(String)} method denies read access to a
1801 * particular root directory, then that directory will not appear in the
1802 * result.
1803 *
1804 * @return An array of {@code File} objects denoting the available
1805 * filesystem roots, or {@code null} if the set of roots could not
1806 * be determined. The array will be empty if there are no
1807 * filesystem roots.
1808 *
1809 * @since 1.2
1810 * @see java.nio.file.FileStore
1811 */
1812 public static File[] listRoots() {
1813 return fs.listRoots();
1814 }
1815
1816
1817 /* -- Disk usage -- */
1818
1819 /**
1820 * Returns the size of the partition <a href="#partName">named</a> by this
1821 * abstract pathname.
1822 *
1823 * @return The size, in bytes, of the partition or {@code 0L} if this
1824 * abstract pathname does not name a partition
1825 *
1826 * @throws SecurityException
1827 * If a security manager has been installed and it denies
1828 * {@link RuntimePermission}{@code ("getFileSystemAttributes")}
1829 * or its {@link SecurityManager#checkRead(String)} method denies
1830 * read access to the file named by this abstract pathname
1831 *
1832 * @since 1.6
1833 */
1834 public long getTotalSpace() {
1835 SecurityManager sm = System.getSecurityManager();
1836 if (sm != null) {
1837 sm.checkPermission(new RuntimePermission("getFileSystemAttributes"));
1838 sm.checkRead(path);
1839 }
1840 if (isInvalid()) {
1841 return 0L;
1842 }
1843 return fs.getSpace(this, FileSystem.SPACE_TOTAL);
1844 }
1845
1846 /**
1847 * Returns the number of unallocated bytes in the partition <a
1848 * href="#partName">named</a> by this abstract path name.
1849 *
1850 * <p> The returned number of unallocated bytes is a hint, but not
1851 * a guarantee, that it is possible to use most or any of these
1852 * bytes. The number of unallocated bytes is most likely to be
1853 * accurate immediately after this call. It is likely to be made
1854 * inaccurate by any external I/O operations including those made
1855 * on the system outside of this virtual machine. This method
1856 * makes no guarantee that write operations to this file system
1857 * will succeed.
1858 *
1859 * @return The number of unallocated bytes on the partition or {@code 0L}
1860 * if the abstract pathname does not name a partition. This
1861 * value will be less than or equal to the total file system size
1862 * returned by {@link #getTotalSpace}.
1863 *
1864 * @throws SecurityException
1865 * If a security manager has been installed and it denies
1866 * {@link RuntimePermission}{@code ("getFileSystemAttributes")}
1867 * or its {@link SecurityManager#checkRead(String)} method denies
1868 * read access to the file named by this abstract pathname
1869 *
1870 * @since 1.6
1871 */
1872 public long getFreeSpace() {
1873 SecurityManager sm = System.getSecurityManager();
1874 if (sm != null) {
1875 sm.checkPermission(new RuntimePermission("getFileSystemAttributes"));
1876 sm.checkRead(path);
1877 }
1878 if (isInvalid()) {
1879 return 0L;
1880 }
1881 return fs.getSpace(this, FileSystem.SPACE_FREE);
1882 }
1883
1884 /**
1885 * Returns the number of bytes available to this virtual machine on the
1886 * partition <a href="#partName">named</a> by this abstract pathname. When
1887 * possible, this method checks for write permissions and other operating
1888 * system restrictions and will therefore usually provide a more accurate
1889 * estimate of how much new data can actually be written than {@link
1890 * #getFreeSpace}.
1891 *
1892 * <p> The returned number of available bytes is a hint, but not a
1893 * guarantee, that it is possible to use most or any of these bytes. The
1894 * number of available bytes is most likely to be accurate immediately
1895 * after this call. It is likely to be made inaccurate by any external
1896 * I/O operations including those made on the system outside of this
1897 * virtual machine. This method makes no guarantee that write operations
1898 * to this file system will succeed.
1899 *
1900 * @return The number of available bytes on the partition or {@code 0L}
1901 * if the abstract pathname does not name a partition. On
1902 * systems where this information is not available, this method
1903 * will be equivalent to a call to {@link #getFreeSpace}.
1904 *
1905 * @throws SecurityException
1906 * If a security manager has been installed and it denies
1907 * {@link RuntimePermission}{@code ("getFileSystemAttributes")}
1908 * or its {@link SecurityManager#checkRead(String)} method denies
1909 * read access to the file named by this abstract pathname
1910 *
1911 * @since 1.6
1912 */
1913 public long getUsableSpace() {
1914 SecurityManager sm = System.getSecurityManager();
1915 if (sm != null) {
1916 sm.checkPermission(new RuntimePermission("getFileSystemAttributes"));
1917 sm.checkRead(path);
1918 }
1919 if (isInvalid()) {
1920 return 0L;
1921 }
1922 return fs.getSpace(this, FileSystem.SPACE_USABLE);
1923 }
1924
1925 /* -- Temporary files -- */
1926
1927 private static class TempDirectory {
1928 private TempDirectory() { }
1929
1930 // temporary directory location
1931 private static final File tmpdir = new File(
1932 GetPropertyAction.privilegedGetProperty("java.io.tmpdir"));
1933 static File location() {
1934 return tmpdir;
1935 }
1936
1937 // file name generation
1938 private static final SecureRandom random = new SecureRandom();
1939 private static int shortenSubName(int subNameLength, int excess,
1940 int nameMin) {
1941 int newLength = Math.max(nameMin, subNameLength - excess);
1942 if (newLength < subNameLength) {
1943 return newLength;
1944 }
1945 return subNameLength;
1946 }
1947 static File generateFile(String prefix, String suffix, File dir)
1948 throws IOException
1949 {
1950 long n = random.nextLong();
1951 String nus = Long.toUnsignedString(n);
1952
1953 // Use only the file name from the supplied prefix
1954 prefix = (new File(prefix)).getName();
1955
1956 int prefixLength = prefix.length();
1957 int nusLength = nus.length();
1958 int suffixLength = suffix.length();;
1959
1960 String name;
1961 int nameMax = fs.getNameMax(dir.getPath());
1962 int excess = prefixLength + nusLength + suffixLength - nameMax;
1963 if (excess <= 0) {
1964 name = prefix + nus + suffix;
1965 } else {
1966 // Name exceeds the maximum path component length: shorten it
1967
1968 // Attempt to shorten the prefix length to no less then 3
1969 prefixLength = shortenSubName(prefixLength, excess, 3);
1970 excess = prefixLength + nusLength + suffixLength - nameMax;
1971
1972 if (excess > 0) {
1973 // Attempt to shorten the suffix length to no less than
1974 // 0 or 4 depending on whether it begins with a dot ('.')
1975 suffixLength = shortenSubName(suffixLength, excess,
1976 suffix.indexOf(".") == 0 ? 4 : 0);
1977 suffixLength = shortenSubName(suffixLength, excess, 3);
1978 excess = prefixLength + nusLength + suffixLength - nameMax;
1979 }
1980
1981 if (excess > 0 && excess <= nusLength - 5) {
1982 // Attempt to shorten the random character string length
1983 // to no less than 5
1984 nusLength = shortenSubName(nusLength, excess, 5);
1985 }
1986
1987 StringBuilder sb =
1988 new StringBuilder(prefixLength + nusLength + suffixLength);
1989 sb.append(prefixLength < prefix.length() ?
1990 prefix.substring(0, prefixLength) : prefix);
1991 sb.append(nusLength < nus.length() ?
1992 nus.substring(0, nusLength) : nus);
1993 sb.append(suffixLength < suffix.length() ?
1994 suffix.substring(0, suffixLength) : suffix);
1995 name = sb.toString();
1996 }
1997
1998 // Normalize the path component
1999 name = fs.normalize(name);
2000
2001 File f = new File(dir, name);
2002 if (!name.equals(f.getName()) || f.isInvalid()) {
2003 if (System.getSecurityManager() != null)
2004 throw new IOException("Unable to create temporary file");
2005 else
2006 throw new IOException("Unable to create temporary file, "
2007 + name);
2008 }
2009 return f;
2010 }
2011 }
2012
2013 /**
2014 * <p> Creates a new empty file in the specified directory, using the
2015 * given prefix and suffix strings to generate its name. If this method
2016 * returns successfully then it is guaranteed that:
2017 *
2018 * <ol>
2019 * <li> The file denoted by the returned abstract pathname did not exist
2020 * before this method was invoked, and
2021 * <li> Neither this method nor any of its variants will return the same
2022 * abstract pathname again in the current invocation of the virtual
2023 * machine.
2024 * </ol>
2025 *
2026 * This method provides only part of a temporary-file facility. To arrange
2027 * for a file created by this method to be deleted automatically, use the
2028 * {@link #deleteOnExit} method.
2029 *
2030 * <p> The <code>prefix</code> argument must be at least three characters
2031 * long. It is recommended that the prefix be a short, meaningful string
2032 * such as <code>"hjb"</code> or <code>"mail"</code>. The
2033 * <code>suffix</code> argument may be <code>null</code>, in which case the
2034 * suffix <code>".tmp"</code> will be used.
2035 *
2036 * <p> To create the new file, the prefix and the suffix may first be
2037 * adjusted to fit the limitations of the underlying platform. If the
2038 * prefix is too long then it will be truncated, but its first three
2039 * characters will always be preserved. If the suffix is too long then it
2040 * too will be truncated, but if it begins with a period character
2041 * (<code>'.'</code>) then the period and the first three characters
2042 * following it will always be preserved. Once these adjustments have been
2043 * made the name of the new file will be generated by concatenating the
2044 * prefix, five or more internally-generated characters, and the suffix.
2045 *
2046 * <p> If the <code>directory</code> argument is <code>null</code> then the
2047 * system-dependent default temporary-file directory will be used. The
2048 * default temporary-file directory is specified by the system property
2049 * <code>java.io.tmpdir</code>. On UNIX systems the default value of this
2050 * property is typically <code>"/tmp"</code> or <code>"/var/tmp"</code>; on
2051 * Microsoft Windows systems it is typically <code>"C:\\WINNT\\TEMP"</code>. A different
2052 * value may be given to this system property when the Java virtual machine
2053 * is invoked, but programmatic changes to this property are not guaranteed
2054 * to have any effect upon the temporary directory used by this method.
2055 *
2056 * @param prefix The prefix string to be used in generating the file's
2057 * name; must be at least three characters long
2058 *
2059 * @param suffix The suffix string to be used in generating the file's
2060 * name; may be <code>null</code>, in which case the
2061 * suffix <code>".tmp"</code> will be used
2062 *
2063 * @param directory The directory in which the file is to be created, or
2064 * <code>null</code> if the default temporary-file
2065 * directory is to be used
2066 *
2067 * @return An abstract pathname denoting a newly-created empty file
2068 *
2069 * @throws IllegalArgumentException
2070 * If the <code>prefix</code> argument contains fewer than three
2071 * characters
2072 *
2073 * @throws IOException If a file could not be created
2074 *
2075 * @throws SecurityException
2076 * If a security manager exists and its {@link
2077 * java.lang.SecurityManager#checkWrite(java.lang.String)}
2078 * method does not allow a file to be created
2079 *
2080 * @since 1.2
2081 */
2082 public static File createTempFile(String prefix, String suffix,
2083 File directory)
2084 throws IOException
2085 {
2086 if (prefix.length() < 3) {
2087 throw new IllegalArgumentException("Prefix string \"" + prefix +
2088 "\" too short: length must be at least 3");
2089 }
2090 if (suffix == null)
2091 suffix = ".tmp";
2092
2093 File tmpdir = (directory != null) ? directory
2094 : TempDirectory.location();
2095 SecurityManager sm = System.getSecurityManager();
2096 File f;
2097 do {
2098 f = TempDirectory.generateFile(prefix, suffix, tmpdir);
2099
2100 if (sm != null) {
2101 try {
2102 sm.checkWrite(f.getPath());
2103 } catch (SecurityException se) {
2104 // don't reveal temporary directory location
2105 if (directory == null)
2106 throw new SecurityException("Unable to create temporary file");
2107 throw se;
2108 }
2109 }
2110 } while ((fs.getBooleanAttributes(f) & FileSystem.BA_EXISTS) != 0);
2111
2112 if (!fs.createFileExclusively(f.getPath()))
2113 throw new IOException("Unable to create temporary file");
2114
2115 return f;
2116 }
2117
2118 /**
2119 * Creates an empty file in the default temporary-file directory, using
2120 * the given prefix and suffix to generate its name. Invoking this method
2121 * is equivalent to invoking {@link #createTempFile(java.lang.String,
2122 * java.lang.String, java.io.File)
2123 * createTempFile(prefix, suffix, null)}.
2124 *
2125 * <p> The {@link
2126 * java.nio.file.Files#createTempFile(String,String,java.nio.file.attribute.FileAttribute[])
2127 * Files.createTempFile} method provides an alternative method to create an
2128 * empty file in the temporary-file directory. Files created by that method
2129 * may have more restrictive access permissions to files created by this
2130 * method and so may be more suited to security-sensitive applications.
2131 *
2132 * @param prefix The prefix string to be used in generating the file's
2133 * name; must be at least three characters long
2134 *
2135 * @param suffix The suffix string to be used in generating the file's
2136 * name; may be <code>null</code>, in which case the
2137 * suffix <code>".tmp"</code> will be used
2138 *
2139 * @return An abstract pathname denoting a newly-created empty file
2140 *
2141 * @throws IllegalArgumentException
2142 * If the <code>prefix</code> argument contains fewer than three
2143 * characters
2144 *
2145 * @throws IOException If a file could not be created
2146 *
2147 * @throws SecurityException
2148 * If a security manager exists and its {@link
2149 * java.lang.SecurityManager#checkWrite(java.lang.String)}
2150 * method does not allow a file to be created
2151 *
2152 * @since 1.2
2153 * @see java.nio.file.Files#createTempDirectory(String,FileAttribute[])
2154 */
2155 public static File createTempFile(String prefix, String suffix)
2156 throws IOException
2157 {
2158 return createTempFile(prefix, suffix, null);
2159 }
2160
2161 /* -- Basic infrastructure -- */
2162
2163 /**
2164 * Compares two abstract pathnames lexicographically. The ordering
2165 * defined by this method depends upon the underlying system. On UNIX
2166 * systems, alphabetic case is significant in comparing pathnames; on Microsoft Windows
2167 * systems it is not.
2168 *
2169 * @param pathname The abstract pathname to be compared to this abstract
2170 * pathname
2171 *
2172 * @return Zero if the argument is equal to this abstract pathname, a
2173 * value less than zero if this abstract pathname is
2174 * lexicographically less than the argument, or a value greater
2175 * than zero if this abstract pathname is lexicographically
2176 * greater than the argument
2177 *
2178 * @since 1.2
2179 */
2180 public int compareTo(File pathname) {
2181 return fs.compare(this, pathname);
2182 }
2183
2184 /**
2185 * Tests this abstract pathname for equality with the given object.
2186 * Returns <code>true</code> if and only if the argument is not
2187 * <code>null</code> and is an abstract pathname that denotes the same file
2188 * or directory as this abstract pathname. Whether or not two abstract
2189 * pathnames are equal depends upon the underlying system. On UNIX
2190 * systems, alphabetic case is significant in comparing pathnames; on Microsoft Windows
2191 * systems it is not.
2192 *
2193 * @param obj The object to be compared with this abstract pathname
2194 *
2195 * @return <code>true</code> if and only if the objects are the same;
2196 * <code>false</code> otherwise
2197 */
2198 public boolean equals(Object obj) {
2199 if ((obj != null) && (obj instanceof File)) {
2200 return compareTo((File)obj) == 0;
2201 }
2202 return false;
2203 }
2204
2205 /**
2206 * Computes a hash code for this abstract pathname. Because equality of
2207 * abstract pathnames is inherently system-dependent, so is the computation
2208 * of their hash codes. On UNIX systems, the hash code of an abstract
2209 * pathname is equal to the exclusive <em>or</em> of the hash code
2210 * of its pathname string and the decimal value
2211 * <code>1234321</code>. On Microsoft Windows systems, the hash
2212 * code is equal to the exclusive <em>or</em> of the hash code of
2213 * its pathname string converted to lower case and the decimal
2214 * value <code>1234321</code>. Locale is not taken into account on
2215 * lowercasing the pathname string.
2216 *
2217 * @return A hash code for this abstract pathname
2218 */
2219 public int hashCode() {
2220 return fs.hashCode(this);
2221 }
2222
2223 /**
2224 * Returns the pathname string of this abstract pathname. This is just the
2225 * string returned by the {@link #getPath} method.
2226 *
2227 * @return The string form of this abstract pathname
2228 */
2229 public String toString() {
2230 return getPath();
2231 }
2232
2233 /**
2234 * WriteObject is called to save this filename.
2235 * The separator character is saved also so it can be replaced
2236 * in case the path is reconstituted on a different host type.
2237 *
2238 * @serialData Default fields followed by separator character.
2239 */
2240 private synchronized void writeObject(java.io.ObjectOutputStream s)
2241 throws IOException
2242 {
2243 s.defaultWriteObject();
2244 s.writeChar(separatorChar); // Add the separator character
2245 }
2246
2247 /**
2248 * readObject is called to restore this filename.
2249 * The original separator character is read. If it is different
2250 * than the separator character on this system, then the old separator
2251 * is replaced by the local separator.
2252 */
2253 private synchronized void readObject(java.io.ObjectInputStream s)
2254 throws IOException, ClassNotFoundException
2255 {
2256 ObjectInputStream.GetField fields = s.readFields();
2257 String pathField = (String)fields.get("path", null);
2258 char sep = s.readChar(); // read the previous separator char
2259 if (sep != separatorChar)
2260 pathField = pathField.replace(sep, separatorChar);
2261 String path = fs.normalize(pathField);
2262 UNSAFE.putReference(this, PATH_OFFSET, path);
2263 UNSAFE.putIntVolatile(this, PREFIX_LENGTH_OFFSET, fs.prefixLength(path));
2264 }
2265
2266 private static final jdk.internal.misc.Unsafe UNSAFE
2267 = jdk.internal.misc.Unsafe.getUnsafe();
2268 private static final long PATH_OFFSET
2269 = UNSAFE.objectFieldOffset(File.class, "path");
2270 private static final long PREFIX_LENGTH_OFFSET
2271 = UNSAFE.objectFieldOffset(File.class, "prefixLength");
2272
2273 /** use serialVersionUID from JDK 1.0.2 for interoperability */
2274 private static final long serialVersionUID = 301077366599181567L;
2275
2276 // -- Integration with java.nio.file --
2277
2278 private transient volatile Path filePath;
2279
2280 /**
2281 * Returns a {@link Path java.nio.file.Path} object constructed from
2282 * this abstract path. The resulting {@code Path} is associated with the
2283 * {@link java.nio.file.FileSystems#getDefault default-filesystem}.
2284 *
2285 * <p> The first invocation of this method works as if invoking it were
2286 * equivalent to evaluating the expression:
2287 * <blockquote><pre>
2288 * {@link java.nio.file.FileSystems#getDefault FileSystems.getDefault}().{@link
2289 * java.nio.file.FileSystem#getPath getPath}(this.{@link #getPath getPath}());
2290 * </pre></blockquote>
2291 * Subsequent invocations of this method return the same {@code Path}.
2292 *
2293 * <p> If this abstract pathname is the empty abstract pathname then this
2294 * method returns a {@code Path} that may be used to access the current
2295 * user directory.
2296 *
2297 * @return a {@code Path} constructed from this abstract path
2298 *
2299 * @throws java.nio.file.InvalidPathException
2300 * if a {@code Path} object cannot be constructed from the abstract
2301 * path (see {@link java.nio.file.FileSystem#getPath FileSystem.getPath})
2302 *
2303 * @since 1.7
2304 * @see Path#toFile
2305 */
2306 public Path toPath() {
2307 Path result = filePath;
2308 if (result == null) {
2309 synchronized (this) {
2310 result = filePath;
2311 if (result == null) {
2312 result = FileSystems.getDefault().getPath(path);
2313 filePath = result;
2314 }
2315 }
2316 }
2317 return result;
2318 }
2319 }