diff options
Diffstat (limited to 'libjava/java/io/File.java')
| -rw-r--r-- | libjava/java/io/File.java | 642 |
1 files changed, 595 insertions, 47 deletions
diff --git a/libjava/java/io/File.java b/libjava/java/io/File.java index 61dedff..83e4c2e 100644 --- a/libjava/java/io/File.java +++ b/libjava/java/io/File.java @@ -81,12 +81,94 @@ public class File implements Serializable, Comparable private final native boolean _access (int query); private final native boolean _stat (int query); + /** + * This is the path separator string for the current host. This field + * contains the value of the <code>file.separator</code> system property. + * An example separator string would be "/" on the GNU system. + */ + public static final String separator = System.getProperty("file.separator"); + + /** + * This is the first character of the file separator string. On many + * hosts (for example, on the GNU system), this represents the entire + * separator string. The complete separator string is obtained from the + * <code>file.separator</code>system property. + */ + public static final char separatorChar = separator.charAt(0); + + /** + * This is the string that is used to separate the host name from the + * path name in paths than include the host name. It is the value of + * the <code>path.separator</code> system property. + */ + public static final String pathSeparator + = System.getProperty("path.separator"); + + /** + * This is the first character of the string used to separate the host name + * from the path name in paths that include a host. The separator string + * is taken from the <code>path.separator</code> system property. + */ + public static final char pathSeparatorChar = pathSeparator.charAt(0); + + + static final String tmpdir = System.getProperty("java.io.tmpdir"); + static int maxPathLen; + static boolean caseSensitive; + static String dupSeparator = separator + separator; + + static + { + init_native(); + } + + // Native function called at class initialization. This should should + // set the maxPathLen and caseSensitive variables. + private static native void init_native(); + + /** + * This is the path to the file set when the object is created. It + * may be an absolute or relative path name. + */ + private String path; + + // We keep a counter for use by createTempFile. We choose the first + // value randomly to try to avoid clashes with other VMs. + private static long counter = Double.doubleToLongBits (Math.random ()); + + /** + * This method tests whether or not the current thread is allowed to + * to read the file pointed to by this object. This will be true if and + * and only if 1) the file exists and 2) the <code>SecurityManager</code> + * (if any) allows access to the file via it's <code>checkRead</code> + * method 3) the file is readable. + * + * @return <code>true</code> if reading is allowed, + * <code>false</code> otherwise + * + * @exception SecurityException If the <code>SecurityManager</code> + * does not allow access to the file + */ public boolean canRead () { checkRead(); return _access (READ); } + /** + * This method test whether or not the current thread is allowed to + * write to this object. This will be true if and only if 1) The + * <code>SecurityManager</code> (if any) allows write access to the + * file and 2) The file exists and 3) The file is writable. To determine + * whether or not a non-existent file can be created, check the parent + * directory for write access. + * + * @return <code>true</code> if writing is allowed, <code>false</code> + * otherwise + * + * @exception SecurityException If the <code>SecurityManager</code> + * does not allow access to the file + */ public boolean canWrite () { checkWrite(); @@ -95,7 +177,23 @@ public class File implements Serializable, Comparable private native boolean performCreate() throws IOException; - /** @since 1.2 */ + /** + * This method creates a new file of zero length with the same name as + * the path of this <code>File</code> object if an only if that file + * does not already exist. + * <p> + * A <code>SecurityManager</code>checkWrite</code> check is done prior + * to performing this action. + * + * @return <code>true</code> if the file was created, <code>false</code> if + * the file alread existed. + * + * @exception IOException If an I/O error occurs + * @exception SecurityException If the <code>SecurityManager</code> will + * not allow this operation to be performed. + * + * @since 1.2 + */ public boolean createNewFile() throws IOException { checkWrite(); @@ -103,6 +201,16 @@ public class File implements Serializable, Comparable } private native boolean performDelete (); + + /** + * This method deletes the file represented by this object. If this file + * is a directory, it must be empty in order for the delete to succeed. + * + * @return <code>true</code> if the file was deleted, <code>false</code> + * otherwise + * + * @exception SecurityException If deleting of the file is not allowed + */ public boolean delete () { SecurityManager s = System.getSecurityManager(); @@ -112,6 +220,21 @@ public class File implements Serializable, Comparable return performDelete (); } + /** + * This method tests two <code>File</code> objects for equality by + * comparing the path of the specified <code>File</code> against the path + * of this object. The two objects are equal if an only if 1) The + * argument is not null 2) The argument is a <code>File</code> object and + * 3) The path of the <code>File</code>argument is equal to the path + * of this object. + * <p> + * The paths of the files are determined by calling the + * <code>getPath()</code> + * method on each object. + * + * @return <code>true</code> if the two objects are equal, + * <code>false</code> otherwise. + */ public boolean equals (Object obj) { if (! (obj instanceof File)) @@ -123,15 +246,29 @@ public class File implements Serializable, Comparable return (path.equalsIgnoreCase(other.path)); } + /** + * This method tests whether or not the file represented by the object + * actually exists on the filesystem. + * + * @return <code>true</code> if the file exists, <code>false</code>otherwise. + * + * @exception SecurityException If reading of the file is not permitted + */ public boolean exists () { checkRead(); return _access (EXISTS); } - public File (String p) + /** + * This method initializes a new <code>File</code> object to represent + * a file with the specified path. + * + * @param name The path name of the file + */ + public File (String name) { - path = normalizePath(p); + path = normalizePath (name); } // Remove duplicate and redundant separator characters. @@ -195,7 +332,17 @@ public class File implements Serializable, Comparable return newpath.toString(); } - + + /** + * This method initializes a new <code>File</code> object to represent + * a file in the specified named directory. The path name to the file + * will be the directory name plus the separator string plus the file + * name. If the directory path name ends in the separator string, another + * separator string will still be appended. + * + * @param dirname The path to the directory the file resides in + * @param name The name of the file + */ public File (String dirPath, String name) { if (name == null) @@ -213,11 +360,30 @@ public class File implements Serializable, Comparable path = normalizePath(name); } - public File (File dir, String name) + /** + * This method initializes a new <code>File</code> object to represent + * a file in the specified directory. If the <code>directory</code> + * argument is <code>null</code>, the file is assumed to be in the + * current directory as specified by the <code>user.dir</code> system + * property + * + * @param directory The directory this file resides in + * @param name The name of the file + */ + public File (File directory, String name) { - this (dir == null ? null : dir.path, name); + this (directory == null ? null : directory.path, name); } + /** + * This method returns the path of this file as an absolute path name. + * If the path name is already absolute, then it is returned. Otherwise + * the value returned is the current directory plus the separatory + * string plus the path of the file. The current directory is determined + * from the <code>user.dir</code> system property. + * + * @return The absolute path of this file + */ public String getAbsolutePath () { if (isAbsolute ()) @@ -234,26 +400,70 @@ public class File implements Serializable, Comparable return System.getProperty ("user.dir") + separatorChar + path; } - /** @since 1.2 */ + /** + * This method returns a <code>File</code> object representing the + * absolute path of this object. + * + * @return A <code>File</code> with the absolute path of the object. + * + * @since 1.2 + */ public File getAbsoluteFile () { return new File (getAbsolutePath()); } + /** + * This method returns a canonical representation of the pathname of + * this file. The actual form of the canonical representation is + * different. On the GNU system, the canonical form differs from the + * absolute form in that all relative file references to "." and ".." + * are resolved and removed. + * <p> + * Note that this method, unlike the other methods which return path + * names, can throw an IOException. This is because native method + * might be required in order to resolve the canonical path + * + * @exception IOException If an error occurs + */ public native String getCanonicalPath () throws IOException; - /** @since 1.2 */ + /** + * This method returns a <code>File</code> object representing the + * canonical path of this object. + * + * @return A <code>File</code> instance representing the canonical path of + * this object. + * + * @exception IOException If an error occurs. + * + * @since 1.2 + */ public File getCanonicalFile () throws IOException { return new File (getCanonicalPath()); } + /** + * This method returns the name of the file. This is everything in the + * complete path of the file after the last instance of the separator + * string. + * + * @return The file name + */ public String getName () { int last = path.lastIndexOf(separatorChar); return path.substring(last + 1); } + /** + * This method returns a <code>String</code> the represents this file's + * parent. <code>null</code> is returned if the file has no parent. The + * parent is determined via a simple operation which removes the + * + * @return The parent directory of this file + */ public String getParent () { int last = path.lastIndexOf(separatorChar); @@ -265,18 +475,40 @@ public class File implements Serializable, Comparable return path.substring(0, last); } - /** @since 1.2 */ + /** + * This method returns a <code>File</code> object representing the parent + * file of this one. + * + * @param A <code>File</code> for the parent of this object. + * <code>null</code> + * will be returned if this object does not have a parent. + * + * @since 1.2 + */ public File getParentFile () { String parent = getParent (); return (parent == null ? null : new File (parent)); } + /** + * Returns the path name that represents this file. May be a relative + * or an absolute path name + * + * @return The pathname of this file + */ public String getPath () { return path; } + /** + * This method returns a hash code representing this file. It is the + * hash code of the path of this file (as returned by <code>getPath()</code>) + * exclusived or-ed with the value 1234321. + * + * @return The hash code for this object + */ public int hashCode () { if (caseSensitive) @@ -285,33 +517,93 @@ public class File implements Serializable, Comparable return (path.toLowerCase().hashCode() ^ 1234321); } + /** + * This method returns true if this object represents an absolute file + * path and false if it does not. The definition of an absolute path varies + * by system. As an example, on GNU systems, a path is absolute if it starts + * with a "/". + * + * @return <code>true</code> if this object represents an absolute + * file name, <code>false</code> otherwise. + */ public native boolean isAbsolute (); + /** + * This method tests whether or not the file represented by this object + * is a directory. In order for this method to return <code>true</code>, + * the file represented by this object must exist and be a directory. + * + * @return <code>true</code> if this file is a directory, <code>false</code> + * otherwise + * + * @exception SecurityException If reading of the file is not permitted + */ public boolean isDirectory () { checkRead(); return _stat (DIRECTORY); } + /** + * This method tests whether or not the file represented by this object + * is a "plain" file. A file is a plain file if and only if it 1) Exists, + * 2) Is not a directory or other type of special file. + * + * @return <code>true</code> if this is a plain file, <code>false</code> + * otherwise + * + * @exception SecurityException If reading of the file is not permitted + */ public boolean isFile () { checkRead(); return _stat (ISFILE); } - /** @since 1.2 */ + /** + * This method tests whether or not this file represents a "hidden" file. + * On GNU systems, a file is hidden if its name begins with a "." + * character. Files with these names are traditionally not shown with + * directory listing tools. + * + * @return <code>true</code> if the file is hidden, <code>false</code> + * otherwise. + * + * @since 1.2 + */ public boolean isHidden() { checkRead(); return _stat (ISHIDDEN); } + /** + * This method returns the last modification time of this file. The + * time value returned is an abstract value that should not be interpreted + * as a specified time value. It is only useful for comparing to other + * such time values returned on the same system. In that case, the larger + * value indicates a more recent modification time. + * <p> + * If the file does not exist, then a value of 0 is returned. + * + * @return The last modification time of the file + * + * @exception SecurityException If reading of the file is not permitted + */ public long lastModified () { checkRead(); return attr (MODIFIED); } + /** + * This method returns the length of the file represented by this object, + * or 0 if the specified file does not exist. + * + * @return The length of the file + * + * @exception SecurityException If reading of the file is not permitted + */ public long length () { checkRead(); @@ -322,44 +614,168 @@ public class File implements Serializable, Comparable FileFilter fileFilter, Class result_type); + /** + * This method returns a array of <code>String</code>'s representing the + * list of files is then directory represented by this object. If this + * object represents a non-directory file or a non-existent file, then + * <code>null</code> is returned. The list of files will not contain + * any names such as "." or ".." which indicate the current or parent + * directory. Also, the names are not guaranteed to be sorted. + * <p> + * In this form of the <code>list()</code> method, a filter is specified + * that allows the caller to control which files are returned in the + * list. The <code>FilenameFilter</code> specified is called for each + * file returned to determine whether or not that file should be included + * in the list. + * <p> + * A <code>SecurityManager</code> check is made prior to reading the + * directory. If read access to the directory is denied, an exception + * will be thrown. + * + * @param filter An object which will identify files to exclude from + * the directory listing. + * + * @return An array of files in the directory, or <code>null</code> + * if this object does not represent a valid directory. + * + * @exception SecurityException If read access is not allowed to the + * directory by the <code>SecurityManager</code> + */ public String[] list (FilenameFilter filter) { checkRead(); return (String[]) performList (filter, null, String.class); } + /** + * This method returns a array of <code>String</code>'s representing the + * list of files is then directory represented by this object. If this + * object represents a non-directory file or a non-existent file, then + * <code>null</code> is returned. The list of files will not contain + * any names such as "." or ".." which indicate the current or parent + * directory. Also, the names are not guaranteed to be sorted. + * <p> + * A <code>SecurityManager</code> check is made prior to reading the + * directory. If read access to the directory is denied, an exception + * will be thrown. + * + * @return An array of files in the directory, or <code>null</code> if + * this object does not represent a valid directory. + * + * @exception SecurityException If read access is not allowed to the + * directory by the <code>SecurityManager</code> + */ public String[] list () { checkRead(); return (String[]) performList (null, null, String.class); } - /** @since 1.2 */ + /** + * This method returns an array of <code>File</code> objects representing + * all the files in the directory represented by this object. If this + * object does not represent a directory, <code>null</code> is returned. + * Each of the returned <code>File</code> object is constructed with this + * object as its parent. + * <p> + * A <code>SecurityManager</code> check is made prior to reading the + * directory. If read access to the directory is denied, an exception + * will be thrown. + * + * @return An array of <code>File</code> objects for this directory. + * + * @exception SecurityException If the <code>SecurityManager</code> denies + * access to this directory. + * + * @since 1.2 + */ public File[] listFiles() { checkRead(); return (File[]) performList (null, null, File.class); } - /** @since 1.2 */ + /** + * This method returns an array of <code>File</code> objects representing + * all the files in the directory represented by this object. If this + * object does not represent a directory, <code>null</code> is returned. + * Each of the returned <code>File</code> object is constructed with this + * object as its parent. + * <p> + * In this form of the <code>listFiles()</code> method, a filter is specified + * that allows the caller to control which files are returned in the + * list. The <code>FilenameFilter</code> specified is called for each + * file returned to determine whether or not that file should be included + * in the list. + * <p> + * A <code>SecurityManager</code> check is made prior to reading the + * directory. If read access to the directory is denied, an exception + * will be thrown. + * + * @return An array of <code>File</code> objects for this directory. + * + * @exception SecurityException If the <code>SecurityManager</code> denies + * access to this directory. + * + * @since 1.2 + */ public File[] listFiles(FilenameFilter filter) { checkRead(); return (File[]) performList (filter, null, File.class); } - /** @since 1.2 */ + /** + * This method returns an array of <code>File</code> objects representing + * all the files in the directory represented by this object. If this + * object does not represent a directory, <code>null</code> is returned. + * Each of the returned <code>File</code> object is constructed with this + * object as its parent. + * <p> + * In this form of the <code>listFiles()</code> method, a filter is specified + * that allows the caller to control which files are returned in the + * list. The <code>FileFilter</code> specified is called for each + * file returned to determine whether or not that file should be included + * in the list. + * <p> + * A <code>SecurityManager</code> check is made prior to reading the + * directory. If read access to the directory is denied, an exception + * will be thrown. + * + * @return An array of <code>File</code> objects for this directory. + * + * @exception SecurityException If the <code>SecurityManager</code> denies + * access to this directory. + * + * @since 1.2 + */ public File[] listFiles(FileFilter filter) { checkRead(); return (File[]) performList (null, filter, File.class); } + /** + * This method returns a <code>String</code> that is the path name of the + * file as returned by <code>getPath</code>. + * + * @return A <code>String</code> representation of this file + */ public String toString () { return path; } + /** + * This method returns a <code>URL</code> with the <code>file:</code> + * protocol that represents this file. The exact form of this URL is + * system dependent. + * + * @return A <code>URL</code> for this object. + * + * @exception MalformedURLException If the URL cannot be created + * successfully. + */ public URL toURL () throws MalformedURLException { // On Win32, Sun's JDK returns URLs of the form "file:/c:/foo/bar.txt", @@ -374,6 +790,14 @@ public class File implements Serializable, Comparable private final native boolean performMkdir (); + /** + * This method creates a directory for the path represented by this object. + * + * @return <code>true</code> if the directory was created, + * <code>false</code> otherwise + * + * @exception SecurityException If write access is not allowed to this file + */ public boolean mkdir () { checkWrite(); @@ -396,6 +820,15 @@ public class File implements Serializable, Comparable return x.mkdir(); } + /** + * This method creates a directory for the path represented by this file. + * It will also create any intervening parent directories if necessary. + * + * @return <code>true</code> if the directory was created, + * <code>false</code> otherwise + * + * @exception SecurityException If write access is not allowed to this file + */ public boolean mkdirs () { checkWrite(); @@ -409,7 +842,36 @@ public class File implements Serializable, Comparable return Long.toString(counter++, Character.MAX_RADIX); } - /** @since 1.2 */ + /** + * This method creates a temporary file in the specified directory. If + * the directory name is null, then this method uses the system temporary + * directory. The files created are guaranteed not to currently exist and + * the same file name will never be used twice in the same virtual + * machine instance. + * The system temporary directory is determined by examinging the + * <code>java.io.tmpdir</code> system property. + * <p> + * The <code>prefix</code> parameter is a sequence of at least three + * characters that are used as the start of the generated filename. The + * <code>suffix</code> parameter is a sequence of characters that is used + * to terminate the file name. This parameter may be <code>null</code> + * and if it is, the suffix defaults to ".tmp". + * <p> + * If a <code>SecurityManager</code> exists, then its <code>checkWrite</code> + * method is used to verify that this operation is permitted. + * + * @param prefix The character prefix to use in generating the path name. + * @param suffix The character suffix to use in generating the path name. + * @param directory The directory to create the file in, or + * <code>null</code> for the default temporary directory + * + * @exception IllegalArgumentException If the patterns is not valid + * @exception SecurityException If there is no permission to perform + * this operation + * @exception IOException If an error occurs + * + * @since 1.2 + */ public static File createTempFile (String prefix, String suffix, File directory) throws IOException @@ -473,7 +935,20 @@ public class File implements Serializable, Comparable private native boolean performSetReadOnly(); - /** @since 1.2 */ + /** + * This method sets the file represented by this object to be read only. + * A read only file or directory cannot be modified. Please note that + * GNU systems allow read only files to be deleted if the directory it + * is contained in is writable. + * + * @return <code>true</code> if the operation succeeded, <code>false</code> + * otherwise. + * + * @exception SecurityException If the <code>SecurityManager</code> does + * not allow this operation. + * + * @since 1.2 + */ public boolean setReadOnly() { checkWrite(); @@ -482,7 +957,17 @@ public class File implements Serializable, Comparable private static native File[] performListRoots(); - /** @since 1.2 */ + /** + * This method returns an array of filesystem roots. Some operating systems + * have volume oriented filesystem. This method provides a mechanism for + * determining which volumes exist. GNU systems use a single hierarchical + * filesystem, so will have only one "/" filesystem root. + * + * @return An array of <code>File</code> objects for each filesystem root + * available. + * + * @since 1.2 + */ public static File[] listRoots() { File[] roots = performListRoots(); @@ -519,13 +1004,55 @@ public class File implements Serializable, Comparable return roots; } + /** + * This method creates a temporary file in the system temporary directory. + * The files created are guaranteed not to currently exist and the same file + * name will never be used twice in the same virtual machine instance. The + * system temporary directory is determined by examinging the + * <code>java.io.tmpdir</code> system property. + * <p> + * The <code>prefix</code> parameter is a sequence of at least three + * characters that are used as the start of the generated filename. The + * <code>suffix</code> parameter is a sequence of characters that is used + * to terminate the file name. This parameter may be <code>null</code> + * and if it is, the suffix defaults to ".tmp". + * <p> + * If a <code>SecurityManager</code> exists, then its <code>checkWrite</code> + * method is used to verify that this operation is permitted. + * <p> + * This method is identical to calling + * <code>createTempFile(prefix, suffix, null)</code>. + * + * @param prefix The character prefix to use in generating the path name. + * @param suffix The character suffix to use in generating the path name. + * + * @exception IllegalArgumentException If the prefix or suffix are not valid. + * @exception SecurityException If there is no permission to perform + * this operation + * @exception IOException If an error occurs + */ public static File createTempFile (String prefix, String suffix) throws IOException { return createTempFile (prefix, suffix, null); } - /** @since 1.2 */ + /** + * This method compares the specified <code>File</code> to this one + * to test for equality. It does this by comparing the canonical path names + * of the files. + * <p> + * The canonical paths of the files are determined by calling the + * <code>getCanonicalPath</code> method on each object. + * <p> + * This method returns a 0 if the specified <code>Object</code> is equal + * to this one, a negative value if it is less than this one + * a positive value if it is greater than this one. + * + * @return An integer as described above + * + * @since 1.2 + */ public int compareTo(File other) { if (caseSensitive) @@ -534,7 +1061,27 @@ public class File implements Serializable, Comparable return path.compareToIgnoreCase (other.path); } - /** @since 1.2 */ + /** + * This method compares the specified <code>Object</code> to this one + * to test for equality. It does this by comparing the canonical path names + * of the files. This method is identical to <code>compareTo(File)</code> + * except that if the <code>Object</code> passed to it is not a + * <code>File</code>, it throws a <code>ClassCastException</code> + * <p> + * The canonical paths of the files are determined by calling the + * <code>getCanonicalPath</code> method on each object. + * <p> + * This method returns a 0 if the specified <code>Object</code> is equal + * to this one, a negative value if it is less than this one + * a positive value if it is greater than this one. + * + * @return An integer as described above + * + * @exception ClassCastException If the passed <code>Object</code> is + * not a <code>File</code> + * + * @since 1.2 + */ public int compareTo(Object o) { File other = (File) o; @@ -542,6 +1089,19 @@ public class File implements Serializable, Comparable } private native boolean performRenameTo (File dest); + + /** + * This method renames the file represented by this object to the path + * of the file represented by the argument <code>File</code>. + * + * @param dest The <code>File</code> object representing the target name + * + * @return <code>true</code> if the rename succeeds, <code>false</code> + * otherwise. + * + * @exception SecurityException If write access is not allowed to the + * file by the <code>SecurityMananger</code>. + */ public boolean renameTo (File dest) { SecurityManager s = System.getSecurityManager(); @@ -556,41 +1116,29 @@ public class File implements Serializable, Comparable } private native boolean performSetLastModified(long time); - - /** @since 1.2 */ + + /** + * This method sets the modification time on the file to the specified + * value. This is specified as the number of seconds since midnight + * on January 1, 1970 GMT. + * + * @param time The desired modification time. + * + * @return <code>true</code> if the operation succeeded, <code>false</code> + * otherwise. + * + * @exception IllegalArgumentException If the specified time is negative. + * @exception SecurityException If the <code>SecurityManager</code> will + * not allow this operation. + * + * @since 1.2 + */ public boolean setLastModified(long time) { checkWrite(); return performSetLastModified(time); } - public static final String pathSeparator - = System.getProperty("path.separator"); - public static final char pathSeparatorChar = pathSeparator.charAt(0); - public static final String separator = System.getProperty("file.separator"); - public static final char separatorChar = separator.charAt(0); - - static final String tmpdir = System.getProperty("java.io.tmpdir"); - static int maxPathLen; - static boolean caseSensitive; - static String dupSeparator = separator + separator; - - static - { - init_native(); - } - - // Native function called at class initialization. This should should - // set the maxPathLen and caseSensitive variables. - private static native void init_native(); - - // The path. - private String path; - - // We keep a counter for use by createTempFile. We choose the first - // value randomly to try to avoid clashes with other VMs. - private static long counter = Double.doubleToLongBits (Math.random ()); - private void checkWrite () { SecurityManager s = System.getSecurityManager(); |