001 /*
002 * Copyright 1998-2005 Sun Microsystems, Inc. All Rights Reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation. Sun designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Sun in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022 * CA 95054 USA or visit www.sun.com if you need additional information or
023 * have any questions.
024 */
025
026 package java.io;
027
028 /**
029 * Package-private abstract class for the local filesystem abstraction.
030 */
031
032 abstract class FileSystem {
033
034 /**
035 * Return the FileSystem object representing this platform's local
036 * filesystem.
037 */
038 public static native FileSystem getFileSystem();
039
040 /* -- Normalization and construction -- */
041
042 /**
043 * Return the local filesystem's name-separator character.
044 */
045 public abstract char getSeparator();
046
047 /**
048 * Return the local filesystem's path-separator character.
049 */
050 public abstract char getPathSeparator();
051
052 /**
053 * Convert the given pathname string to normal form. If the string is
054 * already in normal form then it is simply returned.
055 */
056 public abstract String normalize(String path);
057
058 /**
059 * Compute the length of this pathname string's prefix. The pathname
060 * string must be in normal form.
061 */
062 public abstract int prefixLength(String path);
063
064 /**
065 * Resolve the child pathname string against the parent.
066 * Both strings must be in normal form, and the result
067 * will be in normal form.
068 */
069 public abstract String resolve(String parent, String child);
070
071 /**
072 * Return the parent pathname string to be used when the parent-directory
073 * argument in one of the two-argument File constructors is the empty
074 * pathname.
075 */
076 public abstract String getDefaultParent();
077
078 /**
079 * Post-process the given URI path string if necessary. This is used on
080 * win32, e.g., to transform "/c:/foo" into "c:/foo". The path string
081 * still has slash separators; code in the File class will translate them
082 * after this method returns.
083 */
084 public abstract String fromURIPath(String path);
085
086 /* -- Path operations -- */
087
088 /**
089 * Tell whether or not the given abstract pathname is absolute.
090 */
091 public abstract boolean isAbsolute(File f);
092
093 /**
094 * Resolve the given abstract pathname into absolute form. Invoked by the
095 * getAbsolutePath and getCanonicalPath methods in the File class.
096 */
097 public abstract String resolve(File f);
098
099 public abstract String canonicalize(String path) throws IOException;
100
101 /* -- Attribute accessors -- */
102
103 /* Constants for simple boolean attributes */
104 public static final int BA_EXISTS = 0x01;
105 public static final int BA_REGULAR = 0x02;
106 public static final int BA_DIRECTORY = 0x04;
107 public static final int BA_HIDDEN = 0x08;
108
109 /**
110 * Return the simple boolean attributes for the file or directory denoted
111 * by the given abstract pathname, or zero if it does not exist or some
112 * other I/O error occurs.
113 */
114 public abstract int getBooleanAttributes(File f);
115
116 public static final int ACCESS_READ = 0x04;
117 public static final int ACCESS_WRITE = 0x02;
118 public static final int ACCESS_EXECUTE = 0x01;
119
120 /**
121 * Check whether the file or directory denoted by the given abstract
122 * pathname may be accessed by this process. The second argument specifies
123 * which access, ACCESS_READ, ACCESS_WRITE or ACCESS_EXECUTE, to check.
124 * Return false if access is denied or an I/O error occurs
125 */
126 public abstract boolean checkAccess(File f, int access);
127
128 /**
129 * Set on or off the access permission (to owner only or to all) to the file
130 * or directory denoted by the given abstract pathname, based on the parameters
131 * enable, access and oweronly.
132 */
133 public abstract boolean setPermission(File f, int access,
134 boolean enable, boolean owneronly);
135
136 /**
137 * Return the time at which the file or directory denoted by the given
138 * abstract pathname was last modified, or zero if it does not exist or
139 * some other I/O error occurs.
140 */
141 public abstract long getLastModifiedTime(File f);
142
143 /**
144 * Return the length in bytes of the file denoted by the given abstract
145 * pathname, or zero if it does not exist, is a directory, or some other
146 * I/O error occurs.
147 */
148 public abstract long getLength(File f);
149
150 /* -- File operations -- */
151
152 /**
153 * Create a new empty file with the given pathname. Return
154 * <code>true</code> if the file was created and <code>false</code> if a
155 * file or directory with the given pathname already exists. Throw an
156 * IOException if an I/O error occurs.
157 */
158 public abstract boolean createFileExclusively(String pathname)
159 throws IOException;
160
161 /**
162 * Delete the file or directory denoted by the given abstract pathname,
163 * returning <code>true</code> if and only if the operation succeeds.
164 */
165 public abstract boolean delete(File f);
166
167 /**
168 * List the elements of the directory denoted by the given abstract
169 * pathname. Return an array of strings naming the elements of the
170 * directory if successful; otherwise, return <code>null</code>.
171 */
172 public abstract String[] list(File f);
173
174 /**
175 * Create a new directory denoted by the given abstract pathname,
176 * returning <code>true</code> if and only if the operation succeeds.
177 */
178 public abstract boolean createDirectory(File f);
179
180 /**
181 * Rename the file or directory denoted by the first abstract pathname to
182 * the second abstract pathname, returning <code>true</code> if and only if
183 * the operation succeeds.
184 */
185 public abstract boolean rename(File f1, File f2);
186
187 /**
188 * Set the last-modified time of the file or directory denoted by the
189 * given abstract pathname, returning <code>true</code> if and only if the
190 * operation succeeds.
191 */
192 public abstract boolean setLastModifiedTime(File f, long time);
193
194 /**
195 * Mark the file or directory denoted by the given abstract pathname as
196 * read-only, returning <code>true</code> if and only if the operation
197 * succeeds.
198 */
199 public abstract boolean setReadOnly(File f);
200
201 /* -- Filesystem interface -- */
202
203 /**
204 * List the available filesystem roots.
205 */
206 public abstract File[] listRoots();
207
208 /* -- Disk usage -- */
209 public static final int SPACE_TOTAL = 0;
210 public static final int SPACE_FREE = 1;
211 public static final int SPACE_USABLE = 2;
212
213 public abstract long getSpace(File f, int t);
214
215 /* -- Basic infrastructure -- */
216
217 /**
218 * Compare two abstract pathnames lexicographically.
219 */
220 public abstract int compare(File f1, File f2);
221
222 /**
223 * Compute the hash code of an abstract pathname.
224 */
225 public abstract int hashCode(File f);
226
227 // Flags for enabling/disabling performance optimizations for file
228 // name canonicalization
229 static boolean useCanonCaches = true;
230 static boolean useCanonPrefixCache = true;
231
232 private static boolean getBooleanProperty(String prop,
233 boolean defaultVal) {
234 String val = System.getProperty(prop);
235 if (val == null)
236 return defaultVal;
237 if (val.equalsIgnoreCase("true")) {
238 return true;
239 } else {
240 return false;
241 }
242 }
243
244 static {
245 useCanonCaches = getBooleanProperty("sun.io.useCanonCaches",
246 useCanonCaches);
247 useCanonPrefixCache = getBooleanProperty(
248 "sun.io.useCanonPrefixCache", useCanonPrefixCache);
249 }
250 }
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