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 causes its
1062 * deletion registration reference count to be incremented and the
1063 * file registration order to be updated.
1064 * Deletion will be attempted only for normal termination of the
1065 * virtual machine, as defined by the Java Language Specification.
1066 *
1067 * <p>
1068 * An invocation of this method may be cancelled by invoking
1069 * {@link #cancelDeleteOnExit()}. There must be exactly as many
1070 * cancellation as deletion requests however to unregister the file
1071 * or directory completely from eventual deletion. Cancellation which
1072 * doesn't unregister the file does not affect the order of deletion.
1073 *
1074 * <P>
1075 * Note: this method should <i>not</i> be used for file-locking, as
1076 * the resulting protocol cannot be made to work reliably. The
1077 * {@link java.nio.channels.FileLock FileLock}
1078 * facility should be used instead.
1079 *
1080 * @throws SecurityException
1081 * If a security manager exists and its {@link
1082 * java.lang.SecurityManager#checkDelete} method denies
1083 * delete access to the file
1084 *
1085 * @see #cancelDeleteOnExit
1086 * @see #delete
1087 *
1088 * @since 1.2
1089 */
1090 public void deleteOnExit() {
1091 SecurityManager security = System.getSecurityManager();
1092 if (security != null) {
1093 security.checkDelete(path);
1094 }
1095 if (isInvalid()) {
1096 return;
1097 }
1098 DeleteOnExitHook.deleteOnExit(path);
1099 }
1100
1101 /**
1102 * Cancels a request that the file or directory denoted by this abstract
1103 * pathname be deleted when the virtual machine terminates. Invoking this
1104 * method for a file or directory that is not already registered for
1105 * deletion throws exception. This method will cause the deletion registration
1106 * reference count of a registered file or directory to be decremented but
1107 * will not unregister it unless that count reaches zero neither will it
1108 * change the order of file registration.
1109 *
1110 * <p>
1111 * If a file or directory is registered for deletion but is explicitly
1112 * deleted before normal termination of the virtual machine, then it is
1113 * recommended to call this method to free resources used to track the
1114 * file for deletion.
1115 *
1116 * @throws SecurityException
1117 * If a security manager exists and its {@link
1118 * java.lang.SecurityManager#checkDelete} method denies
1119 * delete access to the file
1120 * @throws IllegalStateException
1121 * If this method is called on the same file unbalanced
1122 * with the {@link #deleteOnExit()}
1123 *
1124 * @see #deleteOnExit
1125 *
1126 * @since 14
1127 */
1128 public void cancelDeleteOnExit() {
1129 SecurityManager security = System.getSecurityManager();
1130 if (security != null) {
1131 security.checkDelete(path);
1132 }
1133 if (isInvalid()) {
1134 return;
1135 }
1136 DeleteOnExitHook.cancelDeleteOnExit(path);
1137 }
1138
1139 /**
1140 * Returns an array of strings naming the files and directories in the
1141 * directory denoted by this abstract pathname.
1142 *
1143 * <p> If this abstract pathname does not denote a directory, then this
1144 * method returns {@code null}. Otherwise an array of strings is
1145 * returned, one for each file or directory in the directory. Names
1146 * denoting the directory itself and the directory's parent directory are
1147 * not included in the result. Each string is a file name rather than a
1148 * complete path.
1149 *
1150 * <p> There is no guarantee that the name strings in the resulting array
1151 * will appear in any specific order; they are not, in particular,
1152 * guaranteed to appear in alphabetical order.
1153 *
1154 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1155 * java.nio.file.Files#newDirectoryStream(Path) newDirectoryStream} method to
1156 * open a directory and iterate over the names of the files in the directory.
1157 * This may use less resources when working with very large directories, and
1158 * may be more responsive when working with remote directories.
1159 *
1160 * @return An array of strings naming the files and directories in the
1161 * directory denoted by this abstract pathname. The array will be
1162 * empty if the directory is empty. Returns {@code null} if
1163 * this abstract pathname does not denote a directory, or if an
1164 * I/O error occurs.
1165 *
1166 * @throws SecurityException
1167 * If a security manager exists and its {@link
1168 * SecurityManager#checkRead(String)} method denies read access to
1169 * the directory
1170 */
1171 public String[] list() {
1172 SecurityManager security = System.getSecurityManager();
1173 if (security != null) {
1174 security.checkRead(path);
1175 }
1176 if (isInvalid()) {
1177 return null;
1178 }
1179 return fs.list(this);
1180 }
1181
1182 /**
1183 * Returns an array of strings naming the files and directories in the
1184 * directory denoted by this abstract pathname that satisfy the specified
1185 * filter. The behavior of this method is the same as that of the
1186 * {@link #list()} method, except that the strings in the returned array
1187 * must satisfy the filter. If the given {@code filter} is {@code null}
1188 * then all names are accepted. Otherwise, a name satisfies the filter if
1189 * and only if the value {@code true} results when the {@link
1190 * FilenameFilter#accept FilenameFilter.accept(File, String)} method
1191 * of the filter is invoked on this abstract pathname and the name of a
1192 * file or directory in the directory that it denotes.
1193 *
1194 * @param filter
1195 * A filename filter
1196 *
1197 * @return An array of strings naming the files and directories in the
1198 * directory denoted by this abstract pathname that were accepted
1199 * by the given {@code filter}. The array will be empty if the
1200 * directory is empty or if no names were accepted by the filter.
1201 * Returns {@code null} if this abstract pathname does not denote
1202 * a directory, or if an I/O error occurs.
1203 *
1204 * @throws SecurityException
1205 * If a security manager exists and its {@link
1206 * SecurityManager#checkRead(String)} method denies read access to
1207 * the directory
1208 *
1209 * @see java.nio.file.Files#newDirectoryStream(Path,String)
1210 */
1211 public String[] list(FilenameFilter filter) {
1212 String names[] = list();
1213 if ((names == null) || (filter == null)) {
1214 return names;
1215 }
1216 List<String> v = new ArrayList<>();
1217 for (int i = 0 ; i < names.length ; i++) {
1218 if (filter.accept(this, names[i])) {
1219 v.add(names[i]);
1220 }
1221 }
1222 return v.toArray(new String[v.size()]);
1223 }
1224
1225 /**
1226 * Returns an array of abstract pathnames denoting the files in the
1227 * directory denoted by this abstract pathname.
1228 *
1229 * <p> If this abstract pathname does not denote a directory, then this
1230 * method returns {@code null}. Otherwise an array of {@code File} objects
1231 * is returned, one for each file or directory in the directory. Pathnames
1232 * denoting the directory itself and the directory's parent directory are
1233 * not included in the result. Each resulting abstract pathname is
1234 * constructed from this abstract pathname using the {@link #File(File,
1235 * String) File(File, String)} constructor. Therefore if this
1236 * pathname is absolute then each resulting pathname is absolute; if this
1237 * pathname is relative then each resulting pathname will be relative to
1238 * the same directory.
1239 *
1240 * <p> There is no guarantee that the name strings in the resulting array
1241 * will appear in any specific order; they are not, in particular,
1242 * guaranteed to appear in alphabetical order.
1243 *
1244 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1245 * java.nio.file.Files#newDirectoryStream(Path) newDirectoryStream} method
1246 * to open a directory and iterate over the names of the files in the
1247 * directory. This may use less resources when working with very large
1248 * directories.
1249 *
1250 * @return An array of abstract pathnames denoting the files and
1251 * directories in the directory denoted by this abstract pathname.
1252 * The array will be empty if the directory is empty. Returns
1253 * {@code null} if this abstract pathname does not denote a
1254 * directory, or if an I/O error occurs.
1255 *
1256 * @throws SecurityException
1257 * If a security manager exists and its {@link
1258 * SecurityManager#checkRead(String)} method denies read access to
1259 * the directory
1260 *
1261 * @since 1.2
1262 */
1263 public File[] listFiles() {
1264 String[] ss = list();
1265 if (ss == null) return null;
1266 int n = ss.length;
1267 File[] fs = new File[n];
1268 for (int i = 0; i < n; i++) {
1269 fs[i] = new File(ss[i], this);
1270 }
1271 return fs;
1272 }
1273
1274 /**
1275 * Returns an array of abstract pathnames denoting the files and
1276 * directories in the directory denoted by this abstract pathname that
1277 * satisfy the specified filter. The behavior of this method is the same
1278 * as that of the {@link #listFiles()} method, except that the pathnames in
1279 * the returned array must satisfy the filter. If the given {@code filter}
1280 * is {@code null} then all pathnames are accepted. Otherwise, a pathname
1281 * satisfies the filter if and only if the value {@code true} results when
1282 * the {@link FilenameFilter#accept
1283 * FilenameFilter.accept(File, String)} method of the filter is
1284 * invoked on this abstract pathname and the name of a file or directory in
1285 * the directory that it denotes.
1286 *
1287 * @param filter
1288 * A filename filter
1289 *
1290 * @return An array of abstract pathnames denoting the files and
1291 * directories in the directory denoted by this abstract pathname.
1292 * The array will be empty if the directory is empty. Returns
1293 * {@code null} if this abstract pathname does not denote a
1294 * directory, or if an I/O error occurs.
1295 *
1296 * @throws SecurityException
1297 * If a security manager exists and its {@link
1298 * SecurityManager#checkRead(String)} method denies read access to
1299 * the directory
1300 *
1301 * @since 1.2
1302 * @see java.nio.file.Files#newDirectoryStream(Path,String)
1303 */
1304 public File[] listFiles(FilenameFilter filter) {
1305 String ss[] = list();
1306 if (ss == null) return null;
1307 ArrayList<File> files = new ArrayList<>();
1308 for (String s : ss)
1309 if ((filter == null) || filter.accept(this, s))
1310 files.add(new File(s, this));
1311 return files.toArray(new File[files.size()]);
1312 }
1313
1314 /**
1315 * Returns an array of abstract pathnames denoting the files and
1316 * directories in the directory denoted by this abstract pathname that
1317 * satisfy the specified filter. The behavior of this method is the same
1318 * as that of the {@link #listFiles()} method, except that the pathnames in
1319 * the returned array must satisfy the filter. If the given {@code filter}
1320 * is {@code null} then all pathnames are accepted. Otherwise, a pathname
1321 * satisfies the filter if and only if the value {@code true} results when
1322 * the {@link FileFilter#accept FileFilter.accept(File)} method of the
1323 * filter is invoked on the pathname.
1324 *
1325 * @param filter
1326 * A file filter
1327 *
1328 * @return An array of abstract pathnames denoting the files and
1329 * directories in the directory denoted by this abstract pathname.
1330 * The array will be empty if the directory is empty. Returns
1331 * {@code null} if this abstract pathname does not denote a
1332 * directory, or if an I/O error occurs.
1333 *
1334 * @throws SecurityException
1335 * If a security manager exists and its {@link
1336 * SecurityManager#checkRead(String)} method denies read access to
1337 * the directory
1338 *
1339 * @since 1.2
1340 * @see java.nio.file.Files#newDirectoryStream(Path,java.nio.file.DirectoryStream.Filter)
1341 */
1342 public File[] listFiles(FileFilter filter) {
1343 String ss[] = list();
1344 if (ss == null) return null;
1345 ArrayList<File> files = new ArrayList<>();
1346 for (String s : ss) {
1347 File f = new File(s, this);
1348 if ((filter == null) || filter.accept(f))
1349 files.add(f);
1350 }
1351 return files.toArray(new File[files.size()]);
1352 }
1353
1354 /**
1355 * Creates the directory named by this abstract pathname.
1356 *
1357 * @return <code>true</code> if and only if the directory was
1358 * created; <code>false</code> otherwise
1359 *
1360 * @throws SecurityException
1361 * If a security manager exists and its {@link
1362 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1363 * method does not permit the named directory to be created
1364 */
1365 public boolean mkdir() {
1366 SecurityManager security = System.getSecurityManager();
1367 if (security != null) {
1368 security.checkWrite(path);
1369 }
1370 if (isInvalid()) {
1371 return false;
1372 }
1373 return fs.createDirectory(this);
1374 }
1375
1376 /**
1377 * Creates the directory named by this abstract pathname, including any
1378 * necessary but nonexistent parent directories. Note that if this
1379 * operation fails it may have succeeded in creating some of the necessary
1380 * parent directories.
1381 *
1382 * @return <code>true</code> if and only if the directory was created,
1383 * along with all necessary parent directories; <code>false</code>
1384 * otherwise
1385 *
1386 * @throws SecurityException
1387 * If a security manager exists and its {@link
1388 * java.lang.SecurityManager#checkRead(java.lang.String)}
1389 * method does not permit verification of the existence of the
1390 * named directory and all necessary parent directories; or if
1391 * the {@link
1392 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1393 * method does not permit the named directory and all necessary
1394 * parent directories to be created
1395 */
1396 public boolean mkdirs() {
1397 if (exists()) {
1398 return false;
1399 }
1400 if (mkdir()) {
1401 return true;
1402 }
1403 File canonFile = null;
1404 try {
1405 canonFile = getCanonicalFile();
1406 } catch (IOException e) {
1407 return false;
1408 }
1409
1410 File parent = canonFile.getParentFile();
1411 return (parent != null && (parent.mkdirs() || parent.exists()) &&
1412 canonFile.mkdir());
1413 }
1414
1415 /**
1416 * Renames the file denoted by this abstract pathname.
1417 *
1418 * <p> Many aspects of the behavior of this method are inherently
1419 * platform-dependent: The rename operation might not be able to move a
1420 * file from one filesystem to another, it might not be atomic, and it
1421 * might not succeed if a file with the destination abstract pathname
1422 * already exists. The return value should always be checked to make sure
1423 * that the rename operation was successful.
1424 *
1425 * <p> Note that the {@link java.nio.file.Files} class defines the {@link
1426 * java.nio.file.Files#move move} method to move or rename a file in a
1427 * platform independent manner.
1428 *
1429 * @param dest The new abstract pathname for the named file
1430 *
1431 * @return <code>true</code> if and only if the renaming succeeded;
1432 * <code>false</code> otherwise
1433 *
1434 * @throws SecurityException
1435 * If a security manager exists and its {@link
1436 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1437 * method denies write access to either the old or new pathnames
1438 *
1439 * @throws NullPointerException
1440 * If parameter <code>dest</code> is <code>null</code>
1441 */
1442 public boolean renameTo(File dest) {
1443 if (dest == null) {
1444 throw new NullPointerException();
1445 }
1446 SecurityManager security = System.getSecurityManager();
1447 if (security != null) {
1448 security.checkWrite(path);
1449 security.checkWrite(dest.path);
1450 }
1451 if (this.isInvalid() || dest.isInvalid()) {
1452 return false;
1453 }
1454 return fs.rename(this, dest);
1455 }
1456
1457 /**
1458 * Sets the last-modified time of the file or directory named by this
1459 * abstract pathname.
1460 *
1461 * <p> All platforms support file-modification times to the nearest second,
1462 * but some provide more precision. The argument will be truncated to fit
1463 * the supported precision. If the operation succeeds and no intervening
1464 * operations on the file take place, then the next invocation of the
1465 * {@link #lastModified} method will return the (possibly
1466 * truncated) <code>time</code> argument that was passed to this method.
1467 *
1468 * @param time The new last-modified time, measured in milliseconds since
1469 * the epoch (00:00:00 GMT, January 1, 1970)
1470 *
1471 * @return <code>true</code> if and only if the operation succeeded;
1472 * <code>false</code> otherwise
1473 *
1474 * @throws IllegalArgumentException If the argument is negative
1475 *
1476 * @throws SecurityException
1477 * If a security manager exists and its {@link
1478 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1479 * method denies write access to the named file
1480 *
1481 * @since 1.2
1482 */
1483 public boolean setLastModified(long time) {
1484 if (time < 0) throw new IllegalArgumentException("Negative time");
1485 SecurityManager security = System.getSecurityManager();
1486 if (security != null) {
1487 security.checkWrite(path);
1488 }
1489 if (isInvalid()) {
1490 return false;
1491 }
1492 return fs.setLastModifiedTime(this, time);
1493 }
1494
1495 /**
1496 * Marks the file or directory named by this abstract pathname so that
1497 * only read operations are allowed. After invoking this method the file
1498 * or directory will not change until it is either deleted or marked
1499 * to allow write access. On some platforms it may be possible to start the
1500 * Java virtual machine with special privileges that allow it to modify
1501 * files that are marked read-only. Whether or not a read-only file or
1502 * directory may be deleted depends upon the underlying system.
1503 *
1504 * @return <code>true</code> if and only if the operation succeeded;
1505 * <code>false</code> otherwise
1506 *
1507 * @throws SecurityException
1508 * If a security manager exists and its {@link
1509 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1510 * method denies write access to the named file
1511 *
1512 * @since 1.2
1513 */
1514 public boolean setReadOnly() {
1515 SecurityManager security = System.getSecurityManager();
1516 if (security != null) {
1517 security.checkWrite(path);
1518 }
1519 if (isInvalid()) {
1520 return false;
1521 }
1522 return fs.setReadOnly(this);
1523 }
1524
1525 /**
1526 * Sets the owner's or everybody's write permission for this abstract
1527 * pathname. On some platforms it may be possible to start the Java virtual
1528 * machine with special privileges that allow it to modify files that
1529 * disallow write operations.
1530 *
1531 * <p> The {@link java.nio.file.Files} class defines methods that operate on
1532 * file attributes including file permissions. This may be used when finer
1533 * manipulation of file permissions is required.
1534 *
1535 * @param writable
1536 * If <code>true</code>, sets the access permission to allow write
1537 * operations; if <code>false</code> to disallow write operations
1538 *
1539 * @param ownerOnly
1540 * If <code>true</code>, the write permission applies only to the
1541 * owner's write permission; otherwise, it applies to everybody. If
1542 * the underlying file system can not distinguish the owner's write
1543 * permission from that of others, then the permission will apply to
1544 * everybody, regardless of this value.
1545 *
1546 * @return <code>true</code> if and only if the operation succeeded. The
1547 * operation will fail if the user does not have permission to change
1548 * the access permissions of this abstract pathname.
1549 *
1550 * @throws SecurityException
1551 * If a security manager exists and its {@link
1552 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1553 * method denies write access to the named file
1554 *
1555 * @since 1.6
1556 */
1557 public boolean setWritable(boolean writable, boolean ownerOnly) {
1558 SecurityManager security = System.getSecurityManager();
1559 if (security != null) {
1560 security.checkWrite(path);
1561 }
1562 if (isInvalid()) {
1563 return false;
1564 }
1565 return fs.setPermission(this, FileSystem.ACCESS_WRITE, writable, ownerOnly);
1566 }
1567
1568 /**
1569 * A convenience method to set the owner's write permission for this abstract
1570 * pathname. On some platforms it may be possible to start the Java virtual
1571 * machine with special privileges that allow it to modify files that
1572 * disallow write operations.
1573 *
1574 * <p> An invocation of this method of the form {@code file.setWritable(arg)}
1575 * behaves in exactly the same way as the invocation
1576 *
1577 * <pre>{@code
1578 * file.setWritable(arg, true)
1579 * }</pre>
1580 *
1581 * @param writable
1582 * If <code>true</code>, sets the access permission to allow write
1583 * operations; if <code>false</code> to disallow write operations
1584 *
1585 * @return <code>true</code> if and only if the operation succeeded. The
1586 * operation will fail if the user does not have permission to
1587 * change the access permissions of this abstract pathname.
1588 *
1589 * @throws SecurityException
1590 * If a security manager exists and its {@link
1591 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1592 * method denies write access to the file
1593 *
1594 * @since 1.6
1595 */
1596 public boolean setWritable(boolean writable) {
1597 return setWritable(writable, true);
1598 }
1599
1600 /**
1601 * Sets the owner's or everybody's read permission for this abstract
1602 * pathname. On some platforms it may be possible to start the Java virtual
1603 * machine with special privileges that allow it to read files that are
1604 * marked as unreadable.
1605 *
1606 * <p> The {@link java.nio.file.Files} class defines methods that operate on
1607 * file attributes including file permissions. This may be used when finer
1608 * manipulation of file permissions is required.
1609 *
1610 * @param readable
1611 * If <code>true</code>, sets the access permission to allow read
1612 * operations; if <code>false</code> to disallow read operations
1613 *
1614 * @param ownerOnly
1615 * If <code>true</code>, the read permission applies only to the
1616 * owner's read permission; otherwise, it applies to everybody. If
1617 * the underlying file system can not distinguish the owner's read
1618 * permission from that of others, then the permission will apply to
1619 * everybody, regardless of this value.
1620 *
1621 * @return <code>true</code> if and only if the operation succeeded. The
1622 * operation will fail if the user does not have permission to
1623 * change the access permissions of this abstract pathname. If
1624 * <code>readable</code> is <code>false</code> and the underlying
1625 * file system does not implement a read permission, then the
1626 * operation will fail.
1627 *
1628 * @throws SecurityException
1629 * If a security manager exists and its {@link
1630 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1631 * method denies write access to the file
1632 *
1633 * @since 1.6
1634 */
1635 public boolean setReadable(boolean readable, boolean ownerOnly) {
1636 SecurityManager security = System.getSecurityManager();
1637 if (security != null) {
1638 security.checkWrite(path);
1639 }
1640 if (isInvalid()) {
1641 return false;
1642 }
1643 return fs.setPermission(this, FileSystem.ACCESS_READ, readable, ownerOnly);
1644 }
1645
1646 /**
1647 * A convenience method to set the owner's read permission for this abstract
1648 * pathname. On some platforms it may be possible to start the Java virtual
1649 * machine with special privileges that allow it to read files that are
1650 * marked as unreadable.
1651 *
1652 * <p>An invocation of this method of the form {@code file.setReadable(arg)}
1653 * behaves in exactly the same way as the invocation
1654 *
1655 * <pre>{@code
1656 * file.setReadable(arg, true)
1657 * }</pre>
1658 *
1659 * @param readable
1660 * If <code>true</code>, sets the access permission to allow read
1661 * operations; if <code>false</code> to disallow read operations
1662 *
1663 * @return <code>true</code> if and only if the operation succeeded. The
1664 * operation will fail if the user does not have permission to
1665 * change the access permissions of this abstract pathname. If
1666 * <code>readable</code> is <code>false</code> and the underlying
1667 * file system does not implement a read permission, then the
1668 * operation will fail.
1669 *
1670 * @throws SecurityException
1671 * If a security manager exists and its {@link
1672 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1673 * method denies write access to the file
1674 *
1675 * @since 1.6
1676 */
1677 public boolean setReadable(boolean readable) {
1678 return setReadable(readable, true);
1679 }
1680
1681 /**
1682 * Sets the owner's or everybody's execute permission for this abstract
1683 * pathname. On some platforms it may be possible to start the Java virtual
1684 * machine with special privileges that allow it to execute files that are
1685 * not marked executable.
1686 *
1687 * <p> The {@link java.nio.file.Files} class defines methods that operate on
1688 * file attributes including file permissions. This may be used when finer
1689 * manipulation of file permissions is required.
1690 *
1691 * @param executable
1692 * If <code>true</code>, sets the access permission to allow execute
1693 * operations; if <code>false</code> to disallow execute operations
1694 *
1695 * @param ownerOnly
1696 * If <code>true</code>, the execute permission applies only to the
1697 * owner's execute permission; otherwise, it applies to everybody.
1698 * If the underlying file system can not distinguish the owner's
1699 * execute permission from that of others, then the permission will
1700 * apply to everybody, regardless of this value.
1701 *
1702 * @return <code>true</code> if and only if the operation succeeded. The
1703 * operation will fail if the user does not have permission to
1704 * change the access permissions of this abstract pathname. If
1705 * <code>executable</code> is <code>false</code> and the underlying
1706 * file system does not implement an execute permission, then the
1707 * operation will fail.
1708 *
1709 * @throws SecurityException
1710 * If a security manager exists and its {@link
1711 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1712 * method denies write access to the file
1713 *
1714 * @since 1.6
1715 */
1716 public boolean setExecutable(boolean executable, boolean ownerOnly) {
1717 SecurityManager security = System.getSecurityManager();
1718 if (security != null) {
1719 security.checkWrite(path);
1720 }
1721 if (isInvalid()) {
1722 return false;
1723 }
1724 return fs.setPermission(this, FileSystem.ACCESS_EXECUTE, executable, ownerOnly);
1725 }
1726
1727 /**
1728 * A convenience method to set the owner's execute permission for this
1729 * abstract pathname. On some platforms it may be possible to start the Java
1730 * virtual machine with special privileges that allow it to execute files
1731 * that are not marked executable.
1732 *
1733 * <p>An invocation of this method of the form {@code file.setExcutable(arg)}
1734 * behaves in exactly the same way as the invocation
1735 *
1736 * <pre>{@code
1737 * file.setExecutable(arg, true)
1738 * }</pre>
1739 *
1740 * @param executable
1741 * If <code>true</code>, sets the access permission to allow execute
1742 * operations; if <code>false</code> to disallow execute operations
1743 *
1744 * @return <code>true</code> if and only if the operation succeeded. The
1745 * operation will fail if the user does not have permission to
1746 * change the access permissions of this abstract pathname. If
1747 * <code>executable</code> is <code>false</code> and the underlying
1748 * file system does not implement an execute permission, then the
1749 * operation will fail.
1750 *
1751 * @throws SecurityException
1752 * If a security manager exists and its {@link
1753 * java.lang.SecurityManager#checkWrite(java.lang.String)}
1754 * method denies write access to the file
1755 *
1756 * @since 1.6
1757 */
1758 public boolean setExecutable(boolean executable) {
1759 return setExecutable(executable, true);
1760 }
1761
1762 /**
1763 * Tests whether the application can execute the file denoted by this
1764 * abstract pathname. On some platforms it may be possible to start the
1765 * Java virtual machine with special privileges that allow it to execute
1766 * files that are not marked executable. Consequently this method may return
1767 * {@code true} even though the file does not have execute permissions.
1768 *
1769 * @return <code>true</code> if and only if the abstract pathname exists
1770 * <em>and</em> the application is allowed to execute the file
1771 *
1772 * @throws SecurityException
1773 * If a security manager exists and its {@link
1774 * java.lang.SecurityManager#checkExec(java.lang.String)}
1775 * method denies execute access to the file
1776 *
1777 * @since 1.6
1778 */
1779 public boolean canExecute() {
1780 SecurityManager security = System.getSecurityManager();
1781 if (security != null) {
1782 security.checkExec(path);
1783 }
1784 if (isInvalid()) {
1785 return false;
1786 }
1787 return fs.checkAccess(this, FileSystem.ACCESS_EXECUTE);
1788 }
1789
1790
1791 /* -- Filesystem interface -- */
1792
1793 /**
1794 * List the available filesystem roots.
1795 *
1796 * <p> A particular Java platform may support zero or more
1797 * hierarchically-organized file systems. Each file system has a
1798 * {@code root} directory from which all other files in that file system
1799 * can be reached. Windows platforms, for example, have a root directory
1800 * for each active drive; UNIX platforms have a single root directory,
1801 * namely {@code "/"}. The set of available filesystem roots is affected
1802 * by various system-level operations such as the insertion or ejection of
1803 * removable media and the disconnecting or unmounting of physical or
1804 * virtual disk drives.
1805 *
1806 * <p> This method returns an array of {@code File} objects that denote the
1807 * root directories of the available filesystem roots. It is guaranteed
1808 * that the canonical pathname of any file physically present on the local
1809 * machine will begin with one of the roots returned by this method.
1810 *
1811 * <p> The canonical pathname of a file that resides on some other machine
1812 * and is accessed via a remote-filesystem protocol such as SMB or NFS may
1813 * or may not begin with one of the roots returned by this method. If the
1814 * pathname of a remote file is syntactically indistinguishable from the
1815 * pathname of a local file then it will begin with one of the roots
1816 * returned by this method. Thus, for example, {@code File} objects
1817 * denoting the root directories of the mapped network drives of a Windows
1818 * platform will be returned by this method, while {@code File} objects
1819 * containing UNC pathnames will not be returned by this method.
1820 *
1821 * <p> Unlike most methods in this class, this method does not throw
1822 * security exceptions. If a security manager exists and its {@link
1823 * SecurityManager#checkRead(String)} method denies read access to a
1824 * particular root directory, then that directory will not appear in the
1825 * result.
1826 *
1827 * @return An array of {@code File} objects denoting the available
1828 * filesystem roots, or {@code null} if the set of roots could not
1829 * be determined. The array will be empty if there are no
1830 * filesystem roots.
1831 *
1832 * @since 1.2
1833 * @see java.nio.file.FileStore
1834 */
1835 public static File[] listRoots() {
1836 return fs.listRoots();
1837 }
1838
1839
1840 /* -- Disk usage -- */
1841
1842 /**
1843 * Returns the size of the partition <a href="#partName">named</a> by this
1844 * abstract pathname.
1845 *
1846 * @return The size, in bytes, of the partition or {@code 0L} if this
1847 * abstract pathname does not name a partition
1848 *
1849 * @throws SecurityException
1850 * If a security manager has been installed and it denies
1851 * {@link RuntimePermission}{@code ("getFileSystemAttributes")}
1852 * or its {@link SecurityManager#checkRead(String)} method denies
1853 * read access to the file named by this abstract pathname
1854 *
1855 * @since 1.6
1856 */
1857 public long getTotalSpace() {
1858 SecurityManager sm = System.getSecurityManager();
1859 if (sm != null) {
1860 sm.checkPermission(new RuntimePermission("getFileSystemAttributes"));
1861 sm.checkRead(path);
1862 }
1863 if (isInvalid()) {
1864 return 0L;
1865 }
1866 return fs.getSpace(this, FileSystem.SPACE_TOTAL);
1867 }
1868
1869 /**
1870 * Returns the number of unallocated bytes in the partition <a
1871 * href="#partName">named</a> by this abstract path name.
1872 *
1873 * <p> The returned number of unallocated bytes is a hint, but not
1874 * a guarantee, that it is possible to use most or any of these
1875 * bytes. The number of unallocated bytes is most likely to be
1876 * accurate immediately after this call. It is likely to be made
1877 * inaccurate by any external I/O operations including those made
1878 * on the system outside of this virtual machine. This method
1879 * makes no guarantee that write operations to this file system
1880 * will succeed.
1881 *
1882 * @return The number of unallocated bytes on the partition or {@code 0L}
1883 * if the abstract pathname does not name a partition. This
1884 * value will be less than or equal to the total file system size
1885 * returned by {@link #getTotalSpace}.
1886 *
1887 * @throws SecurityException
1888 * If a security manager has been installed and it denies
1889 * {@link RuntimePermission}{@code ("getFileSystemAttributes")}
1890 * or its {@link SecurityManager#checkRead(String)} method denies
1891 * read access to the file named by this abstract pathname
1892 *
1893 * @since 1.6
1894 */
1895 public long getFreeSpace() {
1896 SecurityManager sm = System.getSecurityManager();
1897 if (sm != null) {
1898 sm.checkPermission(new RuntimePermission("getFileSystemAttributes"));
1899 sm.checkRead(path);
1900 }
1901 if (isInvalid()) {
1902 return 0L;
1903 }
1904 return fs.getSpace(this, FileSystem.SPACE_FREE);
1905 }
1906
1907 /**
1908 * Returns the number of bytes available to this virtual machine on the
1909 * partition <a href="#partName">named</a> by this abstract pathname. When
1910 * possible, this method checks for write permissions and other operating
1911 * system restrictions and will therefore usually provide a more accurate
1912 * estimate of how much new data can actually be written than {@link
1913 * #getFreeSpace}.
1914 *
1915 * <p> The returned number of available bytes is a hint, but not a
1916 * guarantee, that it is possible to use most or any of these bytes. The
1917 * number of available bytes is most likely to be accurate immediately
1918 * after this call. It is likely to be made inaccurate by any external
1919 * I/O operations including those made on the system outside of this
1920 * virtual machine. This method makes no guarantee that write operations
1921 * to this file system will succeed.
1922 *
1923 * @return The number of available bytes on the partition or {@code 0L}
1924 * if the abstract pathname does not name a partition. On
1925 * systems where this information is not available, this method
1926 * will be equivalent to a call to {@link #getFreeSpace}.
1927 *
1928 * @throws SecurityException
1929 * If a security manager has been installed and it denies
1930 * {@link RuntimePermission}{@code ("getFileSystemAttributes")}
1931 * or its {@link SecurityManager#checkRead(String)} method denies
1932 * read access to the file named by this abstract pathname
1933 *
1934 * @since 1.6
1935 */
1936 public long getUsableSpace() {
1937 SecurityManager sm = System.getSecurityManager();
1938 if (sm != null) {
1939 sm.checkPermission(new RuntimePermission("getFileSystemAttributes"));
1940 sm.checkRead(path);
1941 }
1942 if (isInvalid()) {
1943 return 0L;
1944 }
1945 return fs.getSpace(this, FileSystem.SPACE_USABLE);
1946 }
1947
1948 /* -- Temporary files -- */
1949
1950 private static class TempDirectory {
1951 private TempDirectory() { }
1952
1953 // temporary directory location
1954 private static final File tmpdir = new File(
1955 GetPropertyAction.privilegedGetProperty("java.io.tmpdir"));
1956 static File location() {
1957 return tmpdir;
1958 }
1959
1960 // file name generation
1961 private static final SecureRandom random = new SecureRandom();
1962 private static int shortenSubName(int subNameLength, int excess,
1963 int nameMin) {
1964 int newLength = Math.max(nameMin, subNameLength - excess);
1965 if (newLength < subNameLength) {
1966 return newLength;
1967 }
1968 return subNameLength;
1969 }
1970 static File generateFile(String prefix, String suffix, File dir)
1971 throws IOException
1972 {
1973 long n = random.nextLong();
1974 String nus = Long.toUnsignedString(n);
1975
1976 // Use only the file name from the supplied prefix
1977 prefix = (new File(prefix)).getName();
1978
1979 int prefixLength = prefix.length();
1980 int nusLength = nus.length();
1981 int suffixLength = suffix.length();;
1982
1983 String name;
1984 int nameMax = fs.getNameMax(dir.getPath());
1985 int excess = prefixLength + nusLength + suffixLength - nameMax;
1986 if (excess <= 0) {
1987 name = prefix + nus + suffix;
1988 } else {
1989 // Name exceeds the maximum path component length: shorten it
1990
1991 // Attempt to shorten the prefix length to no less then 3
1992 prefixLength = shortenSubName(prefixLength, excess, 3);
1993 excess = prefixLength + nusLength + suffixLength - nameMax;
1994
1995 if (excess > 0) {
1996 // Attempt to shorten the suffix length to no less than
1997 // 0 or 4 depending on whether it begins with a dot ('.')
1998 suffixLength = shortenSubName(suffixLength, excess,
1999 suffix.indexOf(".") == 0 ? 4 : 0);
2000 suffixLength = shortenSubName(suffixLength, excess, 3);
2001 excess = prefixLength + nusLength + suffixLength - nameMax;
2002 }
2003
2004 if (excess > 0 && excess <= nusLength - 5) {
2005 // Attempt to shorten the random character string length
2006 // to no less than 5
2007 nusLength = shortenSubName(nusLength, excess, 5);
2008 }
2009
2010 StringBuilder sb =
2011 new StringBuilder(prefixLength + nusLength + suffixLength);
2012 sb.append(prefixLength < prefix.length() ?
2013 prefix.substring(0, prefixLength) : prefix);
2014 sb.append(nusLength < nus.length() ?
2015 nus.substring(0, nusLength) : nus);
2016 sb.append(suffixLength < suffix.length() ?
2017 suffix.substring(0, suffixLength) : suffix);
2018 name = sb.toString();
2019 }
2020
2021 // Normalize the path component
2022 name = fs.normalize(name);
2023
2024 File f = new File(dir, name);
2025 if (!name.equals(f.getName()) || f.isInvalid()) {
2026 if (System.getSecurityManager() != null)
2027 throw new IOException("Unable to create temporary file");
2028 else
2029 throw new IOException("Unable to create temporary file, "
2030 + name);
2031 }
2032 return f;
2033 }
2034 }
2035
2036 /**
2037 * <p> Creates a new empty file in the specified directory, using the
2038 * given prefix and suffix strings to generate its name. If this method
2039 * returns successfully then it is guaranteed that:
2040 *
2041 * <ol>
2042 * <li> The file denoted by the returned abstract pathname did not exist
2043 * before this method was invoked, and
2044 * <li> Neither this method nor any of its variants will return the same
2045 * abstract pathname again in the current invocation of the virtual
2046 * machine.
2047 * </ol>
2048 *
2049 * This method provides only part of a temporary-file facility. To arrange
2050 * for a file created by this method to be deleted automatically, use the
2051 * {@link #deleteOnExit} method.
2052 *
2053 * <p> The <code>prefix</code> argument must be at least three characters
2054 * long. It is recommended that the prefix be a short, meaningful string
2055 * such as <code>"hjb"</code> or <code>"mail"</code>. The
2056 * <code>suffix</code> argument may be <code>null</code>, in which case the
2057 * suffix <code>".tmp"</code> will be used.
2058 *
2059 * <p> To create the new file, the prefix and the suffix may first be
2060 * adjusted to fit the limitations of the underlying platform. If the
2061 * prefix is too long then it will be truncated, but its first three
2062 * characters will always be preserved. If the suffix is too long then it
2063 * too will be truncated, but if it begins with a period character
2064 * (<code>'.'</code>) then the period and the first three characters
2065 * following it will always be preserved. Once these adjustments have been
2066 * made the name of the new file will be generated by concatenating the
2067 * prefix, five or more internally-generated characters, and the suffix.
2068 *
2069 * <p> If the <code>directory</code> argument is <code>null</code> then the
2070 * system-dependent default temporary-file directory will be used. The
2071 * default temporary-file directory is specified by the system property
2072 * <code>java.io.tmpdir</code>. On UNIX systems the default value of this
2073 * property is typically <code>"/tmp"</code> or <code>"/var/tmp"</code>; on
2074 * Microsoft Windows systems it is typically <code>"C:\\WINNT\\TEMP"</code>. A different
2075 * value may be given to this system property when the Java virtual machine
2076 * is invoked, but programmatic changes to this property are not guaranteed
2077 * to have any effect upon the temporary directory used by this method.
2078 *
2079 * @param prefix The prefix string to be used in generating the file's
2080 * name; must be at least three characters long
2081 *
2082 * @param suffix The suffix string to be used in generating the file's
2083 * name; may be <code>null</code>, in which case the
2084 * suffix <code>".tmp"</code> will be used
2085 *
2086 * @param directory The directory in which the file is to be created, or
2087 * <code>null</code> if the default temporary-file
2088 * directory is to be used
2089 *
2090 * @return An abstract pathname denoting a newly-created empty file
2091 *
2092 * @throws IllegalArgumentException
2093 * If the <code>prefix</code> argument contains fewer than three
2094 * characters
2095 *
2096 * @throws IOException If a file could not be created
2097 *
2098 * @throws SecurityException
2099 * If a security manager exists and its {@link
2100 * java.lang.SecurityManager#checkWrite(java.lang.String)}
2101 * method does not allow a file to be created
2102 *
2103 * @since 1.2
2104 */
2105 public static File createTempFile(String prefix, String suffix,
2106 File directory)
2107 throws IOException
2108 {
2109 if (prefix.length() < 3) {
2110 throw new IllegalArgumentException("Prefix string \"" + prefix +
2111 "\" too short: length must be at least 3");
2112 }
2113 if (suffix == null)
2114 suffix = ".tmp";
2115
2116 File tmpdir = (directory != null) ? directory
2117 : TempDirectory.location();
2118 SecurityManager sm = System.getSecurityManager();
2119 File f;
2120 do {
2121 f = TempDirectory.generateFile(prefix, suffix, tmpdir);
2122
2123 if (sm != null) {
2124 try {
2125 sm.checkWrite(f.getPath());
2126 } catch (SecurityException se) {
2127 // don't reveal temporary directory location
2128 if (directory == null)
2129 throw new SecurityException("Unable to create temporary file");
2130 throw se;
2131 }
2132 }
2133 } while ((fs.getBooleanAttributes(f) & FileSystem.BA_EXISTS) != 0);
2134
2135 if (!fs.createFileExclusively(f.getPath()))
2136 throw new IOException("Unable to create temporary file");
2137
2138 return f;
2139 }
2140
2141 /**
2142 * Creates an empty file in the default temporary-file directory, using
2143 * the given prefix and suffix to generate its name. Invoking this method
2144 * is equivalent to invoking {@link #createTempFile(java.lang.String,
2145 * java.lang.String, java.io.File)
2146 * createTempFile(prefix, suffix, null)}.
2147 *
2148 * <p> The {@link
2149 * java.nio.file.Files#createTempFile(String,String,java.nio.file.attribute.FileAttribute[])
2150 * Files.createTempFile} method provides an alternative method to create an
2151 * empty file in the temporary-file directory. Files created by that method
2152 * may have more restrictive access permissions to files created by this
2153 * method and so may be more suited to security-sensitive applications.
2154 *
2155 * @param prefix The prefix string to be used in generating the file's
2156 * name; must be at least three characters long
2157 *
2158 * @param suffix The suffix string to be used in generating the file's
2159 * name; may be <code>null</code>, in which case the
2160 * suffix <code>".tmp"</code> will be used
2161 *
2162 * @return An abstract pathname denoting a newly-created empty file
2163 *
2164 * @throws IllegalArgumentException
2165 * If the <code>prefix</code> argument contains fewer than three
2166 * characters
2167 *
2168 * @throws IOException If a file could not be created
2169 *
2170 * @throws SecurityException
2171 * If a security manager exists and its {@link
2172 * java.lang.SecurityManager#checkWrite(java.lang.String)}
2173 * method does not allow a file to be created
2174 *
2175 * @since 1.2
2176 * @see java.nio.file.Files#createTempDirectory(String,FileAttribute[])
2177 */
2178 public static File createTempFile(String prefix, String suffix)
2179 throws IOException
2180 {
2181 return createTempFile(prefix, suffix, null);
2182 }
2183
2184 /* -- Basic infrastructure -- */
2185
2186 /**
2187 * Compares two abstract pathnames lexicographically. The ordering
2188 * defined by this method depends upon the underlying system. On UNIX
2189 * systems, alphabetic case is significant in comparing pathnames; on Microsoft Windows
2190 * systems it is not.
2191 *
2192 * @param pathname The abstract pathname to be compared to this abstract
2193 * pathname
2194 *
2195 * @return Zero if the argument is equal to this abstract pathname, a
2196 * value less than zero if this abstract pathname is
2197 * lexicographically less than the argument, or a value greater
2198 * than zero if this abstract pathname is lexicographically
2199 * greater than the argument
2200 *
2201 * @since 1.2
2202 */
2203 public int compareTo(File pathname) {
2204 return fs.compare(this, pathname);
2205 }
2206
2207 /**
2208 * Tests this abstract pathname for equality with the given object.
2209 * Returns <code>true</code> if and only if the argument is not
2210 * <code>null</code> and is an abstract pathname that denotes the same file
2211 * or directory as this abstract pathname. Whether or not two abstract
2212 * pathnames are equal depends upon the underlying system. On UNIX
2213 * systems, alphabetic case is significant in comparing pathnames; on Microsoft Windows
2214 * systems it is not.
2215 *
2216 * @param obj The object to be compared with this abstract pathname
2217 *
2218 * @return <code>true</code> if and only if the objects are the same;
2219 * <code>false</code> otherwise
2220 */
2221 public boolean equals(Object obj) {
2222 if ((obj != null) && (obj instanceof File)) {
2223 return compareTo((File)obj) == 0;
2224 }
2225 return false;
2226 }
2227
2228 /**
2229 * Computes a hash code for this abstract pathname. Because equality of
2230 * abstract pathnames is inherently system-dependent, so is the computation
2231 * of their hash codes. On UNIX systems, the hash code of an abstract
2232 * pathname is equal to the exclusive <em>or</em> of the hash code
2233 * of its pathname string and the decimal value
2234 * <code>1234321</code>. On Microsoft Windows systems, the hash
2235 * code is equal to the exclusive <em>or</em> of the hash code of
2236 * its pathname string converted to lower case and the decimal
2237 * value <code>1234321</code>. Locale is not taken into account on
2238 * lowercasing the pathname string.
2239 *
2240 * @return A hash code for this abstract pathname
2241 */
2242 public int hashCode() {
2243 return fs.hashCode(this);
2244 }
2245
2246 /**
2247 * Returns the pathname string of this abstract pathname. This is just the
2248 * string returned by the {@link #getPath} method.
2249 *
2250 * @return The string form of this abstract pathname
2251 */
2252 public String toString() {
2253 return getPath();
2254 }
2255
2256 /**
2257 * WriteObject is called to save this filename.
2258 * The separator character is saved also so it can be replaced
2259 * in case the path is reconstituted on a different host type.
2260 *
2261 * @serialData Default fields followed by separator character.
2262 */
2263 private synchronized void writeObject(java.io.ObjectOutputStream s)
2264 throws IOException
2265 {
2266 s.defaultWriteObject();
2267 s.writeChar(separatorChar); // Add the separator character
2268 }
2269
2270 /**
2271 * readObject is called to restore this filename.
2272 * The original separator character is read. If it is different
2273 * than the separator character on this system, then the old separator
2274 * is replaced by the local separator.
2275 */
2276 private synchronized void readObject(java.io.ObjectInputStream s)
2277 throws IOException, ClassNotFoundException
2278 {
2279 ObjectInputStream.GetField fields = s.readFields();
2280 String pathField = (String)fields.get("path", null);
2281 char sep = s.readChar(); // read the previous separator char
2282 if (sep != separatorChar)
2283 pathField = pathField.replace(sep, separatorChar);
2284 String path = fs.normalize(pathField);
2285 UNSAFE.putReference(this, PATH_OFFSET, path);
2286 UNSAFE.putIntVolatile(this, PREFIX_LENGTH_OFFSET, fs.prefixLength(path));
2287 }
2288
2289 private static final jdk.internal.misc.Unsafe UNSAFE
2290 = jdk.internal.misc.Unsafe.getUnsafe();
2291 private static final long PATH_OFFSET
2292 = UNSAFE.objectFieldOffset(File.class, "path");
2293 private static final long PREFIX_LENGTH_OFFSET
2294 = UNSAFE.objectFieldOffset(File.class, "prefixLength");
2295
2296 /** use serialVersionUID from JDK 1.0.2 for interoperability */
2297 private static final long serialVersionUID = 301077366599181567L;
2298
2299 // -- Integration with java.nio.file --
2300
2301 private transient volatile Path filePath;
2302
2303 /**
2304 * Returns a {@link Path java.nio.file.Path} object constructed from
2305 * this abstract path. The resulting {@code Path} is associated with the
2306 * {@link java.nio.file.FileSystems#getDefault default-filesystem}.
2307 *
2308 * <p> The first invocation of this method works as if invoking it were
2309 * equivalent to evaluating the expression:
2310 * <blockquote><pre>
2311 * {@link java.nio.file.FileSystems#getDefault FileSystems.getDefault}().{@link
2312 * java.nio.file.FileSystem#getPath getPath}(this.{@link #getPath getPath}());
2313 * </pre></blockquote>
2314 * Subsequent invocations of this method return the same {@code Path}.
2315 *
2316 * <p> If this abstract pathname is the empty abstract pathname then this
2317 * method returns a {@code Path} that may be used to access the current
2318 * user directory.
2319 *
2320 * @return a {@code Path} constructed from this abstract path
2321 *
2322 * @throws java.nio.file.InvalidPathException
2323 * if a {@code Path} object cannot be constructed from the abstract
2324 * path (see {@link java.nio.file.FileSystem#getPath FileSystem.getPath})
2325 *
2326 * @since 1.7
2327 * @see Path#toFile
2328 */
2329 public Path toPath() {
2330 Path result = filePath;
2331 if (result == null) {
2332 synchronized (this) {
2333 result = filePath;
2334 if (result == null) {
2335 result = FileSystems.getDefault().getPath(path);
2336 filePath = result;
2337 }
2338 }
2339 }
2340 return result;
2341 }
2342 }