1 /*
2 * Copyright (c) 1994, 2016, 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 *
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20 *
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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.util.List;
33 import java.util.ArrayList;
34 import java.security.SecureRandom;
35 import java.nio.file.Path;
36 import java.nio.file.FileSystems;
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 name="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 * <h3>Interoperability with {@code java.nio.file} package</h3>
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.equals(""));
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.equals("")) {
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.equals("")) {
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.equals(""))
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 * <p> Where it is required to distinguish an I/O exception from the case
920 * where {@code 0L} is returned, or where several attributes of the
921 * same file are required at the same time, or where the time of last
922 * access or the creation time are required, then the {@link
923 * java.nio.file.Files#readAttributes(Path,Class,LinkOption[])
924 * Files.readAttributes} method may be used.
925 *
926 * @return A <code>long</code> value representing the time the file was
927 * last modified, measured in milliseconds since the epoch
928 * (00:00:00 GMT, January 1, 1970), or <code>0L</code> if the
929 * file does not exist or if an I/O error occurs
930 *
931 * @throws SecurityException
932 * If a security manager exists and its {@link
933 * java.lang.SecurityManager#checkRead(java.lang.String)}
934 * method denies read access to the file
935 */
936 public long lastModified() {
937 SecurityManager security = System.getSecurityManager();
938 if (security != null) {
939 security.checkRead(path);
940 }
941 if (isInvalid()) {
942 return 0L;
943 }
944 return fs.getLastModifiedTime(this);
945 }
946
947 /**
948 * Returns the length of the file denoted by this abstract pathname.
949 * The return value is unspecified if this pathname denotes a directory.
950 *
951 * <p> Where it is required to distinguish an I/O exception from the case
952 * that {@code 0L} is returned, or where several attributes of the same file
953 * are required at the same time, then the {@link
954 * java.nio.file.Files#readAttributes(Path,Class,LinkOption[])
955 * Files.readAttributes} method may be used.
956 *
957 * @return The length, in bytes, of the file denoted by this abstract
958 * pathname, or <code>0L</code> if the file does not exist. Some
959 * operating systems may return <code>0L</code> for pathnames
960 * denoting system-dependent entities such as devices or pipes.
961 *
962 * @throws SecurityException
963 * If a security manager exists and its {@link
964 * java.lang.SecurityManager#checkRead(java.lang.String)}
965 * method denies read access to the file
966 */
967 public long length() {
968 SecurityManager security = System.getSecurityManager();
969 if (security != null) {
970 security.checkRead(path);
971 }
972 if (isInvalid()) {
973 return 0L;
974 }
975 return fs.getLength(this);
976 }
977
978
979 /* -- File operations -- */
980
981 /**
982 * Atomically creates a new, empty file named by this abstract pathname if
983 * and only if a file with this name does not yet exist. The check for the
984 * existence of the file and the creation of the file if it does not exist
985 * are a single operation that is atomic with respect to all other
986 * filesystem activities that might affect the file.
987 * <P>
988 * Note: this method should <i>not</i> be used for file-locking, as
989 * the resulting protocol cannot be made to work reliably. The
990 * {@link java.nio.channels.FileLock FileLock}
991 * facility should be used instead.
992 *
993 * @return <code>true</code> if the named file does not exist and was
994 * successfully created; <code>false</code> if the named file
995 * already exists
996 *
997 * @throws IOException
998 * If an I/O error occurred
999 *
1000 * @throws SecurityException
1001 * If a security manager exists and its {@link
1002 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1003 * method denies write access to the file
1004 *
1005 * @since 1.2
1006 */
1007 public boolean createNewFile() throws IOException {
1008 SecurityManager security = System.getSecurityManager();
1009 if (security != null) security.checkWrite(path);
1010 if (isInvalid()) {
1011 throw new IOException("Invalid file path");
1012 }
1013 return fs.createFileExclusively(path);
1014 }
1015
1016 /**
1017 * Deletes the file or directory denoted by this abstract pathname. If
1018 * this pathname denotes a directory, then the directory must be empty in
1019 * order to be deleted.
1020 *
1021 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1022 * java.nio.file.Files#delete(Path) delete} method to throw an {@link IOException}
1023 * when a file cannot be deleted. This is useful for error reporting and to
1024 * diagnose why a file cannot be deleted.
1025 *
1026 * @return <code>true</code> if and only if the file or directory is
1027 * successfully deleted; <code>false</code> otherwise
1028 *
1029 * @throws SecurityException
1030 * If a security manager exists and its {@link
1031 * java.lang.SecurityManager#checkDelete} method denies
1032 * delete access to the file
1033 */
1034 public boolean delete() {
1035 SecurityManager security = System.getSecurityManager();
1036 if (security != null) {
1037 security.checkDelete(path);
1038 }
1039 if (isInvalid()) {
1040 return false;
1041 }
1042 return fs.delete(this);
1043 }
1044
1045 /**
1046 * Requests that the file or directory denoted by this abstract
1047 * pathname be deleted when the virtual machine terminates.
1048 * Files (or directories) are deleted in the reverse order that
1049 * they are registered. Invoking this method to delete a file or
1050 * directory that is already registered for deletion has no effect.
1051 * Deletion will be attempted only for normal termination of the
1052 * virtual machine, as defined by the Java Language Specification.
1053 *
1054 * <p> Once deletion has been requested, it is not possible to cancel the
1055 * request. This method should therefore be used with care.
1056 *
1057 * <P>
1058 * Note: this method should <i>not</i> be used for file-locking, as
1059 * the resulting protocol cannot be made to work reliably. The
1060 * {@link java.nio.channels.FileLock FileLock}
1061 * facility should be used instead.
1062 *
1063 * @throws SecurityException
1064 * If a security manager exists and its {@link
1065 * java.lang.SecurityManager#checkDelete} method denies
1066 * delete access to the file
1067 *
1068 * @see #delete
1069 *
1070 * @since 1.2
1071 */
1072 public void deleteOnExit() {
1073 SecurityManager security = System.getSecurityManager();
1074 if (security != null) {
1075 security.checkDelete(path);
1076 }
1077 if (isInvalid()) {
1078 return;
1079 }
1080 DeleteOnExitHook.add(path);
1081 }
1082
1083 /**
1084 * Returns an array of strings naming the files and directories in the
1085 * directory denoted by this abstract pathname.
1086 *
1087 * <p> If this abstract pathname does not denote a directory, then this
1088 * method returns {@code null}. Otherwise an array of strings is
1089 * returned, one for each file or directory in the directory. Names
1090 * denoting the directory itself and the directory's parent directory are
1091 * not included in the result. Each string is a file name rather than a
1092 * complete path.
1093 *
1094 * <p> There is no guarantee that the name strings in the resulting array
1095 * will appear in any specific order; they are not, in particular,
1096 * guaranteed to appear in alphabetical order.
1097 *
1098 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1099 * java.nio.file.Files#newDirectoryStream(Path) newDirectoryStream} method to
1100 * open a directory and iterate over the names of the files in the directory.
1101 * This may use less resources when working with very large directories, and
1102 * may be more responsive when working with remote directories.
1103 *
1104 * @return An array of strings naming the files and directories in the
1105 * directory denoted by this abstract pathname. The array will be
1106 * empty if the directory is empty. Returns {@code null} if
1107 * this abstract pathname does not denote a directory, or if an
1108 * I/O error occurs.
1109 *
1110 * @throws SecurityException
1111 * If a security manager exists and its {@link
1112 * SecurityManager#checkRead(String)} method denies read access to
1113 * the directory
1114 */
1115 public String[] list() {
1116 SecurityManager security = System.getSecurityManager();
1117 if (security != null) {
1118 security.checkRead(path);
1119 }
1120 if (isInvalid()) {
1121 return null;
1122 }
1123 return fs.list(this);
1124 }
1125
1126 /**
1127 * Returns an array of strings naming the files and directories in the
1128 * directory denoted by this abstract pathname that satisfy the specified
1129 * filter. The behavior of this method is the same as that of the
1130 * {@link #list()} method, except that the strings in the returned array
1131 * must satisfy the filter. If the given {@code filter} is {@code null}
1132 * then all names are accepted. Otherwise, a name satisfies the filter if
1133 * and only if the value {@code true} results when the {@link
1134 * FilenameFilter#accept FilenameFilter.accept(File, String)} method
1135 * of the filter is invoked on this abstract pathname and the name of a
1136 * file or directory in the directory that it denotes.
1137 *
1138 * @param filter
1139 * A filename filter
1140 *
1141 * @return An array of strings naming the files and directories in the
1142 * directory denoted by this abstract pathname that were accepted
1143 * by the given {@code filter}. The array will be empty if the
1144 * directory is empty or if no names were accepted by the filter.
1145 * Returns {@code null} if this abstract pathname does not denote
1146 * a directory, or if an I/O error occurs.
1147 *
1148 * @throws SecurityException
1149 * If a security manager exists and its {@link
1150 * SecurityManager#checkRead(String)} method denies read access to
1151 * the directory
1152 *
1153 * @see java.nio.file.Files#newDirectoryStream(Path,String)
1154 */
1155 public String[] list(FilenameFilter filter) {
1156 String names[] = list();
1157 if ((names == null) || (filter == null)) {
1158 return names;
1159 }
1160 List<String> v = new ArrayList<>();
1161 for (int i = 0 ; i < names.length ; i++) {
1162 if (filter.accept(this, names[i])) {
1163 v.add(names[i]);
1164 }
1165 }
1166 return v.toArray(new String[v.size()]);
1167 }
1168
1169 /**
1170 * Returns an array of abstract pathnames denoting the files in the
1171 * directory denoted by this abstract pathname.
1172 *
1173 * <p> If this abstract pathname does not denote a directory, then this
1174 * method returns {@code null}. Otherwise an array of {@code File} objects
1175 * is returned, one for each file or directory in the directory. Pathnames
1176 * denoting the directory itself and the directory's parent directory are
1177 * not included in the result. Each resulting abstract pathname is
1178 * constructed from this abstract pathname using the {@link #File(File,
1179 * String) File(File, String)} constructor. Therefore if this
1180 * pathname is absolute then each resulting pathname is absolute; if this
1181 * pathname is relative then each resulting pathname will be relative to
1182 * the same directory.
1183 *
1184 * <p> There is no guarantee that the name strings in the resulting array
1185 * will appear in any specific order; they are not, in particular,
1186 * guaranteed to appear in alphabetical order.
1187 *
1188 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1189 * java.nio.file.Files#newDirectoryStream(Path) newDirectoryStream} method
1190 * to open a directory and iterate over the names of the files in the
1191 * directory. This may use less resources when working with very large
1192 * directories.
1193 *
1194 * @return An array of abstract pathnames denoting the files and
1195 * directories in the directory denoted by this abstract pathname.
1196 * The array will be empty if the directory is empty. Returns
1197 * {@code null} if this abstract pathname does not denote a
1198 * directory, or if an I/O error occurs.
1199 *
1200 * @throws SecurityException
1201 * If a security manager exists and its {@link
1202 * SecurityManager#checkRead(String)} method denies read access to
1203 * the directory
1204 *
1205 * @since 1.2
1206 */
1207 public File[] listFiles() {
1208 String[] ss = list();
1209 if (ss == null) return null;
1210 int n = ss.length;
1211 File[] fs = new File[n];
1212 for (int i = 0; i < n; i++) {
1213 fs[i] = new File(ss[i], this);
1214 }
1215 return fs;
1216 }
1217
1218 /**
1219 * Returns an array of abstract pathnames denoting the files and
1220 * directories in the directory denoted by this abstract pathname that
1221 * satisfy the specified filter. The behavior of this method is the same
1222 * as that of the {@link #listFiles()} method, except that the pathnames in
1223 * the returned array must satisfy the filter. If the given {@code filter}
1224 * is {@code null} then all pathnames are accepted. Otherwise, a pathname
1225 * satisfies the filter if and only if the value {@code true} results when
1226 * the {@link FilenameFilter#accept
1227 * FilenameFilter.accept(File, String)} method of the filter is
1228 * invoked on this abstract pathname and the name of a file or directory in
1229 * the directory that it denotes.
1230 *
1231 * @param filter
1232 * A filename filter
1233 *
1234 * @return An array of abstract pathnames denoting the files and
1235 * directories in the directory denoted by this abstract pathname.
1236 * The array will be empty if the directory is empty. Returns
1237 * {@code null} if this abstract pathname does not denote a
1238 * directory, or if an I/O error occurs.
1239 *
1240 * @throws SecurityException
1241 * If a security manager exists and its {@link
1242 * SecurityManager#checkRead(String)} method denies read access to
1243 * the directory
1244 *
1245 * @since 1.2
1246 * @see java.nio.file.Files#newDirectoryStream(Path,String)
1247 */
1248 public File[] listFiles(FilenameFilter filter) {
1249 String ss[] = list();
1250 if (ss == null) return null;
1251 ArrayList<File> files = new ArrayList<>();
1252 for (String s : ss)
1253 if ((filter == null) || filter.accept(this, s))
1254 files.add(new File(s, this));
1255 return files.toArray(new File[files.size()]);
1256 }
1257
1258 /**
1259 * Returns an array of abstract pathnames denoting the files and
1260 * directories in the directory denoted by this abstract pathname that
1261 * satisfy the specified filter. The behavior of this method is the same
1262 * as that of the {@link #listFiles()} method, except that the pathnames in
1263 * the returned array must satisfy the filter. If the given {@code filter}
1264 * is {@code null} then all pathnames are accepted. Otherwise, a pathname
1265 * satisfies the filter if and only if the value {@code true} results when
1266 * the {@link FileFilter#accept FileFilter.accept(File)} method of the
1267 * filter is invoked on the pathname.
1268 *
1269 * @param filter
1270 * A file filter
1271 *
1272 * @return An array of abstract pathnames denoting the files and
1273 * directories in the directory denoted by this abstract pathname.
1274 * The array will be empty if the directory is empty. Returns
1275 * {@code null} if this abstract pathname does not denote a
1276 * directory, or if an I/O error occurs.
1277 *
1278 * @throws SecurityException
1279 * If a security manager exists and its {@link
1280 * SecurityManager#checkRead(String)} method denies read access to
1281 * the directory
1282 *
1283 * @since 1.2
1284 * @see java.nio.file.Files#newDirectoryStream(Path,java.nio.file.DirectoryStream.Filter)
1285 */
1286 public File[] listFiles(FileFilter filter) {
1287 String ss[] = list();
1288 if (ss == null) return null;
1289 ArrayList<File> files = new ArrayList<>();
1290 for (String s : ss) {
1291 File f = new File(s, this);
1292 if ((filter == null) || filter.accept(f))
1293 files.add(f);
1294 }
1295 return files.toArray(new File[files.size()]);
1296 }
1297
1298 /**
1299 * Creates the directory named by this abstract pathname.
1300 *
1301 * @return <code>true</code> if and only if the directory was
1302 * created; <code>false</code> otherwise
1303 *
1304 * @throws SecurityException
1305 * If a security manager exists and its {@link
1306 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1307 * method does not permit the named directory to be created
1308 */
1309 public boolean mkdir() {
1310 SecurityManager security = System.getSecurityManager();
1311 if (security != null) {
1312 security.checkWrite(path);
1313 }
1314 if (isInvalid()) {
1315 return false;
1316 }
1317 return fs.createDirectory(this);
1318 }
1319
1320 /**
1321 * Creates the directory named by this abstract pathname, including any
1322 * necessary but nonexistent parent directories. Note that if this
1323 * operation fails it may have succeeded in creating some of the necessary
1324 * parent directories.
1325 *
1326 * @return <code>true</code> if and only if the directory was created,
1327 * along with all necessary parent directories; <code>false</code>
1328 * otherwise
1329 *
1330 * @throws SecurityException
1331 * If a security manager exists and its {@link
1332 * java.lang.SecurityManager#checkRead(java.lang.String)}
1333 * method does not permit verification of the existence of the
1334 * named directory and all necessary parent directories; or if
1335 * the {@link
1336 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1337 * method does not permit the named directory and all necessary
1338 * parent directories to be created
1339 */
1340 public boolean mkdirs() {
1341 if (exists()) {
1342 return false;
1343 }
1344 if (mkdir()) {
1345 return true;
1346 }
1347 File canonFile = null;
1348 try {
1349 canonFile = getCanonicalFile();
1350 } catch (IOException e) {
1351 return false;
1352 }
1353
1354 File parent = canonFile.getParentFile();
1355 return (parent != null && (parent.mkdirs() || parent.exists()) &&
1356 canonFile.mkdir());
1357 }
1358
1359 /**
1360 * Renames the file denoted by this abstract pathname.
1361 *
1362 * <p> Many aspects of the behavior of this method are inherently
1363 * platform-dependent: The rename operation might not be able to move a
1364 * file from one filesystem to another, it might not be atomic, and it
1365 * might not succeed if a file with the destination abstract pathname
1366 * already exists. The return value should always be checked to make sure
1367 * that the rename operation was successful.
1368 *
1369 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1370 * java.nio.file.Files#move move} method to move or rename a file in a
1371 * platform independent manner.
1372 *
1373 * @param dest The new abstract pathname for the named file
1374 *
1375 * @return <code>true</code> if and only if the renaming succeeded;
1376 * <code>false</code> otherwise
1377 *
1378 * @throws SecurityException
1379 * If a security manager exists and its {@link
1380 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1381 * method denies write access to either the old or new pathnames
1382 *
1383 * @throws NullPointerException
1384 * If parameter <code>dest</code> is <code>null</code>
1385 */
1386 public boolean renameTo(File dest) {
1387 SecurityManager security = System.getSecurityManager();
1388 if (security != null) {
1389 security.checkWrite(path);
1390 security.checkWrite(dest.path);
1391 }
1392 if (dest == null) {
1393 throw new NullPointerException();
1394 }
1395 if (this.isInvalid() || dest.isInvalid()) {
1396 return false;
1397 }
1398 return fs.rename(this, dest);
1399 }
1400
1401 /**
1402 * Sets the last-modified time of the file or directory named by this
1403 * abstract pathname.
1404 *
1405 * <p> All platforms support file-modification times to the nearest second,
1406 * but some provide more precision. The argument will be truncated to fit
1407 * the supported precision. If the operation succeeds and no intervening
1408 * operations on the file take place, then the next invocation of the
1409 * {@link #lastModified} method will return the (possibly
1410 * truncated) <code>time</code> argument that was passed to this method.
1411 *
1412 * @param time The new last-modified time, measured in milliseconds since
1413 * the epoch (00:00:00 GMT, January 1, 1970)
1414 *
1415 * @return <code>true</code> if and only if the operation succeeded;
1416 * <code>false</code> otherwise
1417 *
1418 * @throws IllegalArgumentException If the argument is negative
1419 *
1420 * @throws SecurityException
1421 * If a security manager exists and its {@link
1422 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1423 * method denies write access to the named file
1424 *
1425 * @since 1.2
1426 */
1427 public boolean setLastModified(long time) {
1428 if (time < 0) throw new IllegalArgumentException("Negative time");
1429 SecurityManager security = System.getSecurityManager();
1430 if (security != null) {
1431 security.checkWrite(path);
1432 }
1433 if (isInvalid()) {
1434 return false;
1435 }
1436 return fs.setLastModifiedTime(this, time);
1437 }
1438
1439 /**
1440 * Marks the file or directory named by this abstract pathname so that
1441 * only read operations are allowed. After invoking this method the file
1442 * or directory will not change until it is either deleted or marked
1443 * to allow write access. On some platforms it may be possible to start the
1444 * Java virtual machine with special privileges that allow it to modify
1445 * files that are marked read-only. Whether or not a read-only file or
1446 * directory may be deleted depends upon the underlying system.
1447 *
1448 * @return <code>true</code> if and only if the operation succeeded;
1449 * <code>false</code> otherwise
1450 *
1451 * @throws SecurityException
1452 * If a security manager exists and its {@link
1453 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1454 * method denies write access to the named file
1455 *
1456 * @since 1.2
1457 */
1458 public boolean setReadOnly() {
1459 SecurityManager security = System.getSecurityManager();
1460 if (security != null) {
1461 security.checkWrite(path);
1462 }
1463 if (isInvalid()) {
1464 return false;
1465 }
1466 return fs.setReadOnly(this);
1467 }
1468
1469 /**
1470 * Sets the owner's or everybody's write permission for this abstract
1471 * pathname. On some platforms it may be possible to start the Java virtual
1472 * machine with special privileges that allow it to modify files that
1473 * disallow write operations.
1474 *
1475 * <p> The {@link java.nio.file.Files} class defines methods that operate on
1476 * file attributes including file permissions. This may be used when finer
1477 * manipulation of file permissions is required.
1478 *
1479 * @param writable
1480 * If <code>true</code>, sets the access permission to allow write
1481 * operations; if <code>false</code> to disallow write operations
1482 *
1483 * @param ownerOnly
1484 * If <code>true</code>, the write permission applies only to the
1485 * owner's write permission; otherwise, it applies to everybody. If
1486 * the underlying file system can not distinguish the owner's write
1487 * permission from that of others, then the permission will apply to
1488 * everybody, regardless of this value.
1489 *
1490 * @return <code>true</code> if and only if the operation succeeded. The
1491 * operation will fail if the user does not have permission to change
1492 * the access permissions of this abstract pathname.
1493 *
1494 * @throws SecurityException
1495 * If a security manager exists and its {@link
1496 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1497 * method denies write access to the named file
1498 *
1499 * @since 1.6
1500 */
1501 public boolean setWritable(boolean writable, boolean ownerOnly) {
1502 SecurityManager security = System.getSecurityManager();
1503 if (security != null) {
1504 security.checkWrite(path);
1505 }
1506 if (isInvalid()) {
1507 return false;
1508 }
1509 return fs.setPermission(this, FileSystem.ACCESS_WRITE, writable, ownerOnly);
1510 }
1511
1512 /**
1513 * A convenience method to set the owner's write permission for this abstract
1514 * pathname. On some platforms it may be possible to start the Java virtual
1515 * machine with special privileges that allow it to modify files that
1516 * disallow write operations.
1517 *
1518 * <p> An invocation of this method of the form {@code file.setWritable(arg)}
1519 * behaves in exactly the same way as the invocation
1520 *
1521 * <pre>{@code
1522 * file.setWritable(arg, true)
1523 * }</pre>
1524 *
1525 * @param writable
1526 * If <code>true</code>, sets the access permission to allow write
1527 * operations; if <code>false</code> to disallow write operations
1528 *
1529 * @return <code>true</code> if and only if the operation succeeded. The
1530 * operation will fail if the user does not have permission to
1531 * change the access permissions of this abstract pathname.
1532 *
1533 * @throws SecurityException
1534 * If a security manager exists and its {@link
1535 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1536 * method denies write access to the file
1537 *
1538 * @since 1.6
1539 */
1540 public boolean setWritable(boolean writable) {
1541 return setWritable(writable, true);
1542 }
1543
1544 /**
1545 * Sets the owner's or everybody's read permission for this abstract
1546 * pathname. On some platforms it may be possible to start the Java virtual
1547 * machine with special privileges that allow it to read files that are
1548 * marked as unreadable.
1549 *
1550 * <p> The {@link java.nio.file.Files} class defines methods that operate on
1551 * file attributes including file permissions. This may be used when finer
1552 * manipulation of file permissions is required.
1553 *
1554 * @param readable
1555 * If <code>true</code>, sets the access permission to allow read
1556 * operations; if <code>false</code> to disallow read operations
1557 *
1558 * @param ownerOnly
1559 * If <code>true</code>, the read permission applies only to the
1560 * owner's read permission; otherwise, it applies to everybody. If
1561 * the underlying file system can not distinguish the owner's read
1562 * permission from that of others, then the permission will apply to
1563 * everybody, regardless of this value.
1564 *
1565 * @return <code>true</code> if and only if the operation succeeded. The
1566 * operation will fail if the user does not have permission to
1567 * change the access permissions of this abstract pathname. If
1568 * <code>readable</code> is <code>false</code> and the underlying
1569 * file system does not implement a read permission, then the
1570 * operation will fail.
1571 *
1572 * @throws SecurityException
1573 * If a security manager exists and its {@link
1574 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1575 * method denies write access to the file
1576 *
1577 * @since 1.6
1578 */
1579 public boolean setReadable(boolean readable, boolean ownerOnly) {
1580 SecurityManager security = System.getSecurityManager();
1581 if (security != null) {
1582 security.checkWrite(path);
1583 }
1584 if (isInvalid()) {
1585 return false;
1586 }
1587 return fs.setPermission(this, FileSystem.ACCESS_READ, readable, ownerOnly);
1588 }
1589
1590 /**
1591 * A convenience method to set the owner's read permission for this abstract
1592 * pathname. On some platforms it may be possible to start the Java virtual
1593 * machine with special privileges that allow it to read files that are
1594 * marked as unreadable.
1595 *
1596 * <p>An invocation of this method of the form {@code file.setReadable(arg)}
1597 * behaves in exactly the same way as the invocation
1598 *
1599 * <pre>{@code
1600 * file.setReadable(arg, true)
1601 * }</pre>
1602 *
1603 * @param readable
1604 * If <code>true</code>, sets the access permission to allow read
1605 * operations; if <code>false</code> to disallow read operations
1606 *
1607 * @return <code>true</code> if and only if the operation succeeded. The
1608 * operation will fail if the user does not have permission to
1609 * change the access permissions of this abstract pathname. If
1610 * <code>readable</code> is <code>false</code> and the underlying
1611 * file system does not implement a read permission, then the
1612 * operation will fail.
1613 *
1614 * @throws SecurityException
1615 * If a security manager exists and its {@link
1616 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1617 * method denies write access to the file
1618 *
1619 * @since 1.6
1620 */
1621 public boolean setReadable(boolean readable) {
1622 return setReadable(readable, true);
1623 }
1624
1625 /**
1626 * Sets the owner's or everybody's execute permission for this abstract
1627 * pathname. On some platforms it may be possible to start the Java virtual
1628 * machine with special privileges that allow it to execute files that are
1629 * not marked executable.
1630 *
1631 * <p> The {@link java.nio.file.Files} class defines methods that operate on
1632 * file attributes including file permissions. This may be used when finer
1633 * manipulation of file permissions is required.
1634 *
1635 * @param executable
1636 * If <code>true</code>, sets the access permission to allow execute
1637 * operations; if <code>false</code> to disallow execute operations
1638 *
1639 * @param ownerOnly
1640 * If <code>true</code>, the execute permission applies only to the
1641 * owner's execute permission; otherwise, it applies to everybody.
1642 * If the underlying file system can not distinguish the owner's
1643 * execute permission from that of others, then the permission will
1644 * apply to everybody, regardless of this value.
1645 *
1646 * @return <code>true</code> if and only if the operation succeeded. The
1647 * operation will fail if the user does not have permission to
1648 * change the access permissions of this abstract pathname. If
1649 * <code>executable</code> is <code>false</code> and the underlying
1650 * file system does not implement an execute permission, then the
1651 * operation will fail.
1652 *
1653 * @throws SecurityException
1654 * If a security manager exists and its {@link
1655 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1656 * method denies write access to the file
1657 *
1658 * @since 1.6
1659 */
1660 public boolean setExecutable(boolean executable, boolean ownerOnly) {
1661 SecurityManager security = System.getSecurityManager();
1662 if (security != null) {
1663 security.checkWrite(path);
1664 }
1665 if (isInvalid()) {
1666 return false;
1667 }
1668 return fs.setPermission(this, FileSystem.ACCESS_EXECUTE, executable, ownerOnly);
1669 }
1670
1671 /**
1672 * A convenience method to set the owner's execute permission for this
1673 * abstract pathname. On some platforms it may be possible to start the Java
1674 * virtual machine with special privileges that allow it to execute files
1675 * that are not marked executable.
1676 *
1677 * <p>An invocation of this method of the form {@code file.setExcutable(arg)}
1678 * behaves in exactly the same way as the invocation
1679 *
1680 * <pre>{@code
1681 * file.setExecutable(arg, true)
1682 * }</pre>
1683 *
1684 * @param executable
1685 * If <code>true</code>, sets the access permission to allow execute
1686 * operations; if <code>false</code> to disallow execute operations
1687 *
1688 * @return <code>true</code> if and only if the operation succeeded. The
1689 * operation will fail if the user does not have permission to
1690 * change the access permissions of this abstract pathname. If
1691 * <code>executable</code> is <code>false</code> and the underlying
1692 * file system does not implement an execute permission, then the
1693 * operation will fail.
1694 *
1695 * @throws SecurityException
1696 * If a security manager exists and its {@link
1697 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1698 * method denies write access to the file
1699 *
1700 * @since 1.6
1701 */
1702 public boolean setExecutable(boolean executable) {
1703 return setExecutable(executable, true);
1704 }
1705
1706 /**
1707 * Tests whether the application can execute the file denoted by this
1708 * abstract pathname. On some platforms it may be possible to start the
1709 * Java virtual machine with special privileges that allow it to execute
1710 * files that are not marked executable. Consequently this method may return
1711 * {@code true} even though the file does not have execute permissions.
1712 *
1713 * @return <code>true</code> if and only if the abstract pathname exists
1714 * <em>and</em> the application is allowed to execute the file
1715 *
1716 * @throws SecurityException
1717 * If a security manager exists and its {@link
1718 * java.lang.SecurityManager#checkExec(java.lang.String)}
1719 * method denies execute access to the file
1720 *
1721 * @since 1.6
1722 */
1723 public boolean canExecute() {
1724 SecurityManager security = System.getSecurityManager();
1725 if (security != null) {
1726 security.checkExec(path);
1727 }
1728 if (isInvalid()) {
1729 return false;
1730 }
1731 return fs.checkAccess(this, FileSystem.ACCESS_EXECUTE);
1732 }
1733
1734
1735 /* -- Filesystem interface -- */
1736
1737 /**
1738 * List the available filesystem roots.
1739 *
1740 * <p> A particular Java platform may support zero or more
1741 * hierarchically-organized file systems. Each file system has a
1742 * {@code root} directory from which all other files in that file system
1743 * can be reached. Windows platforms, for example, have a root directory
1744 * for each active drive; UNIX platforms have a single root directory,
1745 * namely {@code "/"}. The set of available filesystem roots is affected
1746 * by various system-level operations such as the insertion or ejection of
1747 * removable media and the disconnecting or unmounting of physical or
1748 * virtual disk drives.
1749 *
1750 * <p> This method returns an array of {@code File} objects that denote the
1751 * root directories of the available filesystem roots. It is guaranteed
1752 * that the canonical pathname of any file physically present on the local
1753 * machine will begin with one of the roots returned by this method.
1754 *
1755 * <p> The canonical pathname of a file that resides on some other machine
1756 * and is accessed via a remote-filesystem protocol such as SMB or NFS may
1757 * or may not begin with one of the roots returned by this method. If the
1758 * pathname of a remote file is syntactically indistinguishable from the
1759 * pathname of a local file then it will begin with one of the roots
1760 * returned by this method. Thus, for example, {@code File} objects
1761 * denoting the root directories of the mapped network drives of a Windows
1762 * platform will be returned by this method, while {@code File} objects
1763 * containing UNC pathnames will not be returned by this method.
1764 *
1765 * <p> Unlike most methods in this class, this method does not throw
1766 * security exceptions. If a security manager exists and its {@link
1767 * SecurityManager#checkRead(String)} method denies read access to a
1768 * particular root directory, then that directory will not appear in the
1769 * result.
1770 *
1771 * @return An array of {@code File} objects denoting the available
1772 * filesystem roots, or {@code null} if the set of roots could not
1773 * be determined. The array will be empty if there are no
1774 * filesystem roots.
1775 *
1776 * @since 1.2
1777 * @see java.nio.file.FileStore
1778 */
1779 public static File[] listRoots() {
1780 return fs.listRoots();
1781 }
1782
1783
1784 /* -- Disk usage -- */
1785
1786 /**
1787 * Returns the size of the partition <a href="#partName">named</a> by this
1788 * abstract pathname.
1789 *
1790 * @return The size, in bytes, of the partition or {@code 0L} if this
1791 * abstract pathname does not name a partition
1792 *
1793 * @throws SecurityException
1794 * If a security manager has been installed and it denies
1795 * {@link RuntimePermission}{@code ("getFileSystemAttributes")}
1796 * or its {@link SecurityManager#checkRead(String)} method denies
1797 * read access to the file named by this abstract pathname
1798 *
1799 * @since 1.6
1800 */
1801 public long getTotalSpace() {
1802 SecurityManager sm = System.getSecurityManager();
1803 if (sm != null) {
1804 sm.checkPermission(new RuntimePermission("getFileSystemAttributes"));
1805 sm.checkRead(path);
1806 }
1807 if (isInvalid()) {
1808 return 0L;
1809 }
1810 return fs.getSpace(this, FileSystem.SPACE_TOTAL);
1811 }
1812
1813 /**
1814 * Returns the number of unallocated bytes in the partition <a
1815 * href="#partName">named</a> by this abstract path name.
1816 *
1817 * <p> The returned number of unallocated bytes is a hint, but not
1818 * a guarantee, that it is possible to use most or any of these
1819 * bytes. The number of unallocated bytes is most likely to be
1820 * accurate immediately after this call. It is likely to be made
1821 * inaccurate by any external I/O operations including those made
1822 * on the system outside of this virtual machine. This method
1823 * makes no guarantee that write operations to this file system
1824 * will succeed.
1825 *
1826 * @return The number of unallocated bytes on the partition or {@code 0L}
1827 * if the abstract pathname does not name a partition. This
1828 * value will be less than or equal to the total file system size
1829 * returned by {@link #getTotalSpace}.
1830 *
1831 * @throws SecurityException
1832 * If a security manager has been installed and it denies
1833 * {@link RuntimePermission}{@code ("getFileSystemAttributes")}
1834 * or its {@link SecurityManager#checkRead(String)} method denies
1835 * read access to the file named by this abstract pathname
1836 *
1837 * @since 1.6
1838 */
1839 public long getFreeSpace() {
1840 SecurityManager sm = System.getSecurityManager();
1841 if (sm != null) {
1842 sm.checkPermission(new RuntimePermission("getFileSystemAttributes"));
1843 sm.checkRead(path);
1844 }
1845 if (isInvalid()) {
1846 return 0L;
1847 }
1848 return fs.getSpace(this, FileSystem.SPACE_FREE);
1849 }
1850
1851 /**
1852 * Returns the number of bytes available to this virtual machine on the
1853 * partition <a href="#partName">named</a> by this abstract pathname. When
1854 * possible, this method checks for write permissions and other operating
1855 * system restrictions and will therefore usually provide a more accurate
1856 * estimate of how much new data can actually be written than {@link
1857 * #getFreeSpace}.
1858 *
1859 * <p> The returned number of available bytes is a hint, but not a
1860 * guarantee, that it is possible to use most or any of these bytes. The
1861 * number of unallocated bytes is most likely to be accurate immediately
1862 * after this call. It is likely to be made inaccurate by any external
1863 * I/O operations including those made on the system outside of this
1864 * virtual machine. This method makes no guarantee that write operations
1865 * to this file system will succeed.
1866 *
1867 * @return The number of available bytes on the partition or {@code 0L}
1868 * if the abstract pathname does not name a partition. On
1869 * systems where this information is not available, this method
1870 * will be equivalent to a call to {@link #getFreeSpace}.
1871 *
1872 * @throws SecurityException
1873 * If a security manager has been installed and it denies
1874 * {@link RuntimePermission}{@code ("getFileSystemAttributes")}
1875 * or its {@link SecurityManager#checkRead(String)} method denies
1876 * read access to the file named by this abstract pathname
1877 *
1878 * @since 1.6
1879 */
1880 public long getUsableSpace() {
1881 SecurityManager sm = System.getSecurityManager();
1882 if (sm != null) {
1883 sm.checkPermission(new RuntimePermission("getFileSystemAttributes"));
1884 sm.checkRead(path);
1885 }
1886 if (isInvalid()) {
1887 return 0L;
1888 }
1889 return fs.getSpace(this, FileSystem.SPACE_USABLE);
1890 }
1891
1892 /* -- Temporary files -- */
1893
1894 private static class TempDirectory {
1895 private TempDirectory() { }
1896
1897 // temporary directory location
1898 private static final File tmpdir = new File(
1899 GetPropertyAction.privilegedGetProperty("java.io.tmpdir"));
1900 static File location() {
1901 return tmpdir;
1902 }
1903
1904 // file name generation
1905 private static final SecureRandom random = new SecureRandom();
1906 static File generateFile(String prefix, String suffix, File dir)
1907 throws IOException
1908 {
1909 long n = random.nextLong();
1910
1911 // Use only the file name from the supplied prefix
1912 prefix = (new File(prefix)).getName();
1913 String name = prefix + Long.toUnsignedString(n) + suffix;
1914 File f = new File(dir, name);
1915 if (!name.equals(f.getName()) || f.isInvalid()) {
1916 if (System.getSecurityManager() != null)
1917 throw new IOException("Unable to create temporary file");
1918 else
1919 throw new IOException("Unable to create temporary file, " + f);
1920 }
1921 return f;
1922 }
1923 }
1924
1925 /**
1926 * <p> Creates a new empty file in the specified directory, using the
1927 * given prefix and suffix strings to generate its name. If this method
1928 * returns successfully then it is guaranteed that:
1929 *
1930 * <ol>
1931 * <li> The file denoted by the returned abstract pathname did not exist
1932 * before this method was invoked, and
1933 * <li> Neither this method nor any of its variants will return the same
1934 * abstract pathname again in the current invocation of the virtual
1935 * machine.
1936 * </ol>
1937 *
1938 * This method provides only part of a temporary-file facility. To arrange
1939 * for a file created by this method to be deleted automatically, use the
1940 * {@link #deleteOnExit} method.
1941 *
1942 * <p> The <code>prefix</code> argument must be at least three characters
1943 * long. It is recommended that the prefix be a short, meaningful string
1944 * such as <code>"hjb"</code> or <code>"mail"</code>. The
1945 * <code>suffix</code> argument may be <code>null</code>, in which case the
1946 * suffix <code>".tmp"</code> will be used.
1947 *
1948 * <p> To create the new file, the prefix and the suffix may first be
1949 * adjusted to fit the limitations of the underlying platform. If the
1950 * prefix is too long then it will be truncated, but its first three
1951 * characters will always be preserved. If the suffix is too long then it
1952 * too will be truncated, but if it begins with a period character
1953 * (<code>'.'</code>) then the period and the first three characters
1954 * following it will always be preserved. Once these adjustments have been
1955 * made the name of the new file will be generated by concatenating the
1956 * prefix, five or more internally-generated characters, and the suffix.
1957 *
1958 * <p> If the <code>directory</code> argument is <code>null</code> then the
1959 * system-dependent default temporary-file directory will be used. The
1960 * default temporary-file directory is specified by the system property
1961 * <code>java.io.tmpdir</code>. On UNIX systems the default value of this
1962 * property is typically <code>"/tmp"</code> or <code>"/var/tmp"</code>; on
1963 * Microsoft Windows systems it is typically <code>"C:\\WINNT\\TEMP"</code>. A different
1964 * value may be given to this system property when the Java virtual machine
1965 * is invoked, but programmatic changes to this property are not guaranteed
1966 * to have any effect upon the temporary directory used by this method.
1967 *
1968 * @param prefix The prefix string to be used in generating the file's
1969 * name; must be at least three characters long
1970 *
1971 * @param suffix The suffix string to be used in generating the file's
1972 * name; may be <code>null</code>, in which case the
1973 * suffix <code>".tmp"</code> will be used
1974 *
1975 * @param directory The directory in which the file is to be created, or
1976 * <code>null</code> if the default temporary-file
1977 * directory is to be used
1978 *
1979 * @return An abstract pathname denoting a newly-created empty file
1980 *
1981 * @throws IllegalArgumentException
1982 * If the <code>prefix</code> argument contains fewer than three
1983 * characters
1984 *
1985 * @throws IOException If a file could not be created
1986 *
1987 * @throws SecurityException
1988 * If a security manager exists and its {@link
1989 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1990 * method does not allow a file to be created
1991 *
1992 * @since 1.2
1993 */
1994 public static File createTempFile(String prefix, String suffix,
1995 File directory)
1996 throws IOException
1997 {
1998 if (prefix.length() < 3) {
1999 throw new IllegalArgumentException("Prefix string \"" + prefix +
2000 "\" too short: length must be at least 3");
2001 }
2002 if (suffix == null)
2003 suffix = ".tmp";
2004
2005 File tmpdir = (directory != null) ? directory
2006 : TempDirectory.location();
2007 SecurityManager sm = System.getSecurityManager();
2008 File f;
2009 do {
2010 f = TempDirectory.generateFile(prefix, suffix, tmpdir);
2011
2012 if (sm != null) {
2013 try {
2014 sm.checkWrite(f.getPath());
2015 } catch (SecurityException se) {
2016 // don't reveal temporary directory location
2017 if (directory == null)
2018 throw new SecurityException("Unable to create temporary file");
2019 throw se;
2020 }
2021 }
2022 } while ((fs.getBooleanAttributes(f) & FileSystem.BA_EXISTS) != 0);
2023
2024 if (!fs.createFileExclusively(f.getPath()))
2025 throw new IOException("Unable to create temporary file");
2026
2027 return f;
2028 }
2029
2030 /**
2031 * Creates an empty file in the default temporary-file directory, using
2032 * the given prefix and suffix to generate its name. Invoking this method
2033 * is equivalent to invoking {@link #createTempFile(java.lang.String,
2034 * java.lang.String, java.io.File)
2035 * createTempFile(prefix, suffix, null)}.
2036 *
2037 * <p> The {@link
2038 * java.nio.file.Files#createTempFile(String,String,java.nio.file.attribute.FileAttribute[])
2039 * Files.createTempFile} method provides an alternative method to create an
2040 * empty file in the temporary-file directory. Files created by that method
2041 * may have more restrictive access permissions to files created by this
2042 * method and so may be more suited to security-sensitive applications.
2043 *
2044 * @param prefix The prefix string to be used in generating the file's
2045 * name; must be at least three characters long
2046 *
2047 * @param suffix The suffix string to be used in generating the file's
2048 * name; may be <code>null</code>, in which case the
2049 * suffix <code>".tmp"</code> will be used
2050 *
2051 * @return An abstract pathname denoting a newly-created empty file
2052 *
2053 * @throws IllegalArgumentException
2054 * If the <code>prefix</code> argument contains fewer than three
2055 * characters
2056 *
2057 * @throws IOException If a file could not be created
2058 *
2059 * @throws SecurityException
2060 * If a security manager exists and its {@link
2061 * java.lang.SecurityManager#checkWrite(java.lang.String)}
2062 * method does not allow a file to be created
2063 *
2064 * @since 1.2
2065 * @see java.nio.file.Files#createTempDirectory(String,FileAttribute[])
2066 */
2067 public static File createTempFile(String prefix, String suffix)
2068 throws IOException
2069 {
2070 return createTempFile(prefix, suffix, null);
2071 }
2072
2073 /* -- Basic infrastructure -- */
2074
2075 /**
2076 * Compares two abstract pathnames lexicographically. The ordering
2077 * defined by this method depends upon the underlying system. On UNIX
2078 * systems, alphabetic case is significant in comparing pathnames; on Microsoft Windows
2079 * systems it is not.
2080 *
2081 * @param pathname The abstract pathname to be compared to this abstract
2082 * pathname
2083 *
2084 * @return Zero if the argument is equal to this abstract pathname, a
2085 * value less than zero if this abstract pathname is
2086 * lexicographically less than the argument, or a value greater
2087 * than zero if this abstract pathname is lexicographically
2088 * greater than the argument
2089 *
2090 * @since 1.2
2091 */
2092 public int compareTo(File pathname) {
2093 return fs.compare(this, pathname);
2094 }
2095
2096 /**
2097 * Tests this abstract pathname for equality with the given object.
2098 * Returns <code>true</code> if and only if the argument is not
2099 * <code>null</code> and is an abstract pathname that denotes the same file
2100 * or directory as this abstract pathname. Whether or not two abstract
2101 * pathnames are equal depends upon the underlying system. On UNIX
2102 * systems, alphabetic case is significant in comparing pathnames; on Microsoft Windows
2103 * systems it is not.
2104 *
2105 * @param obj The object to be compared with this abstract pathname
2106 *
2107 * @return <code>true</code> if and only if the objects are the same;
2108 * <code>false</code> otherwise
2109 */
2110 public boolean equals(Object obj) {
2111 if ((obj != null) && (obj instanceof File)) {
2112 return compareTo((File)obj) == 0;
2113 }
2114 return false;
2115 }
2116
2117 /**
2118 * Computes a hash code for this abstract pathname. Because equality of
2119 * abstract pathnames is inherently system-dependent, so is the computation
2120 * of their hash codes. On UNIX systems, the hash code of an abstract
2121 * pathname is equal to the exclusive <em>or</em> of the hash code
2122 * of its pathname string and the decimal value
2123 * <code>1234321</code>. On Microsoft Windows systems, the hash
2124 * code is equal to the exclusive <em>or</em> of the hash code of
2125 * its pathname string converted to lower case and the decimal
2126 * value <code>1234321</code>. Locale is not taken into account on
2127 * lowercasing the pathname string.
2128 *
2129 * @return A hash code for this abstract pathname
2130 */
2131 public int hashCode() {
2132 return fs.hashCode(this);
2133 }
2134
2135 /**
2136 * Returns the pathname string of this abstract pathname. This is just the
2137 * string returned by the {@link #getPath} method.
2138 *
2139 * @return The string form of this abstract pathname
2140 */
2141 public String toString() {
2142 return getPath();
2143 }
2144
2145 /**
2146 * WriteObject is called to save this filename.
2147 * The separator character is saved also so it can be replaced
2148 * in case the path is reconstituted on a different host type.
2149 *
2150 * @serialData Default fields followed by separator character.
2151 */
2152 private synchronized void writeObject(java.io.ObjectOutputStream s)
2153 throws IOException
2154 {
2155 s.defaultWriteObject();
2156 s.writeChar(separatorChar); // Add the separator character
2157 }
2158
2159 /**
2160 * readObject is called to restore this filename.
2161 * The original separator character is read. If it is different
2162 * than the separator character on this system, then the old separator
2163 * is replaced by the local separator.
2164 */
2165 private synchronized void readObject(java.io.ObjectInputStream s)
2166 throws IOException, ClassNotFoundException
2167 {
2168 ObjectInputStream.GetField fields = s.readFields();
2169 String pathField = (String)fields.get("path", null);
2170 char sep = s.readChar(); // read the previous separator char
2171 if (sep != separatorChar)
2172 pathField = pathField.replace(sep, separatorChar);
2173 String path = fs.normalize(pathField);
2174 UNSAFE.putObject(this, PATH_OFFSET, path);
2175 UNSAFE.putIntVolatile(this, PREFIX_LENGTH_OFFSET, fs.prefixLength(path));
2176 }
2177
2178 private static final long PATH_OFFSET;
2179 private static final long PREFIX_LENGTH_OFFSET;
2180 private static final jdk.internal.misc.Unsafe UNSAFE;
2181 static {
2182 try {
2183 jdk.internal.misc.Unsafe unsafe = jdk.internal.misc.Unsafe.getUnsafe();
2184 PATH_OFFSET = unsafe.objectFieldOffset(
2185 File.class.getDeclaredField("path"));
2186 PREFIX_LENGTH_OFFSET = unsafe.objectFieldOffset(
2187 File.class.getDeclaredField("prefixLength"));
2188 UNSAFE = unsafe;
2189 } catch (ReflectiveOperationException e) {
2190 throw new Error(e);
2191 }
2192 }
2193
2194
2195 /** use serialVersionUID from JDK 1.0.2 for interoperability */
2196 private static final long serialVersionUID = 301077366599181567L;
2197
2198 // -- Integration with java.nio.file --
2199
2200 private transient volatile Path filePath;
2201
2202 /**
2203 * Returns a {@link Path java.nio.file.Path} object constructed from the
2204 * this abstract path. The resulting {@code Path} is associated with the
2205 * {@link java.nio.file.FileSystems#getDefault default-filesystem}.
2206 *
2207 * <p> The first invocation of this method works as if invoking it were
2208 * equivalent to evaluating the expression:
2209 * <blockquote><pre>
2210 * {@link java.nio.file.FileSystems#getDefault FileSystems.getDefault}().{@link
2211 * java.nio.file.FileSystem#getPath getPath}(this.{@link #getPath getPath}());
2212 * </pre></blockquote>
2213 * Subsequent invocations of this method return the same {@code Path}.
2214 *
2215 * <p> If this abstract pathname is the empty abstract pathname then this
2216 * method returns a {@code Path} that may be used to access the current
2217 * user directory.
2218 *
2219 * @return a {@code Path} constructed from this abstract path
2220 *
2221 * @throws java.nio.file.InvalidPathException
2222 * if a {@code Path} object cannot be constructed from the abstract
2223 * path (see {@link java.nio.file.FileSystem#getPath FileSystem.getPath})
2224 *
2225 * @since 1.7
2226 * @see Path#toFile
2227 */
2228 public Path toPath() {
2229 Path result = filePath;
2230 if (result == null) {
2231 synchronized (this) {
2232 result = filePath;
2233 if (result == null) {
2234 result = FileSystems.getDefault().getPath(path);
2235 filePath = result;
2236 }
2237 }
2238 }
2239 return result;
2240 }
2241 }