File	Doc	Category	Size	Date	Package
File.java	API Doc	Java SE 6 API	80715	Tue Jun 10 00:25:32 BST 2008	java.io

File

• java.lang.Object

Fields Summary
private static FileSystem	fs The FileSystem object representing the platform's local file system.
private String	path This abstract pathname's normalized pathname string. A normalized pathname string uses the default name-separator character and does not contain any duplicate or redundant separators.
private transient int	prefixLength The length of this abstract pathname's prefix, or zero if it has no prefix.
public static final char	separatorChar The system-dependent default name-separator character. This field is initialized to contain the first character of the value of the system property file.separator. On UNIX systems the value of this field is '/'; on Microsoft Windows systems it is '\\'.
public static final String	separator The system-dependent default name-separator character, represented as a string for convenience. This string contains a single character, namely {@link #separatorChar}.
public static final char	pathSeparatorChar The system-dependent path-separator character. This field is initialized to contain the first character of the value of the system property path.separator. This character is used to separate filenames in a sequence of files given as a path list. On UNIX systems, this character is ':'; on Microsoft Windows systems it is ';'.
public static final String	pathSeparator The system-dependent path-separator character, represented as a string for convenience. This string contains a single character, namely {@link #pathSeparatorChar}.
private static final Object	tmpFileLock
private static int	counter
private static String	tmpdir
private static final long	serialVersionUID use serialVersionUID from JDK 1.0.2 for interoperability

Constructors Summary
private File(String pathname, int prefixLength) Internal constructor for already-normalized pathname strings.  /* -- Constructors -- */ this.path = pathname; this.prefixLength = prefixLength;
private File(String child, File parent) Internal constructor for already-normalized pathname strings. The parameter order is used to disambiguate this method from the public(File, String) constructor. assert parent.path != null; assert (!parent.path.equals("")); this.path = fs.resolve(parent.path, child); this.prefixLength = parent.prefixLength;
public File(String pathname) Creates a new File instance by converting the given pathname string into an abstract pathname. If the given string is the empty string, then the result is the empty abstract pathname. param pathname A pathname string throws NullPointerException If the pathname argument is null if (pathname == null) { throw new NullPointerException(); } this.path = fs.normalize(pathname); this.prefixLength = fs.prefixLength(this.path);
public File(String parent, String child) Creates a new File instance from a parent pathname string and a child pathname string. If parent is null then the new File instance is created as if by invoking the single-argument File constructor on the given child pathname string. Otherwise the parent pathname string is taken to denote a directory, and the child pathname string is taken to denote either a directory or a file. If the child pathname string is absolute then it is converted into a relative pathname in a system-dependent way. If parent is the empty string then the new File instance is created by converting child into an abstract pathname and resolving the result against a system-dependent default directory. Otherwise each pathname string is converted into an abstract pathname and the child abstract pathname is resolved against the parent. param parent The parent pathname string param child The child pathname string throws NullPointerException If child is null if (child == null) { throw new NullPointerException(); } if (parent != null) { if (parent.equals("")) { this.path = fs.resolve(fs.getDefaultParent(), fs.normalize(child)); } else { this.path = fs.resolve(fs.normalize(parent), fs.normalize(child)); } } else { this.path = fs.normalize(child); } this.prefixLength = fs.prefixLength(this.path);
public File(File parent, String child) Creates a new File instance from a parent abstract pathname and a child pathname string. If parent is null then the new File instance is created as if by invoking the single-argument File constructor on the given child pathname string. Otherwise the parent abstract pathname is taken to denote a directory, and the child pathname string is taken to denote either a directory or a file. If the child pathname string is absolute then it is converted into a relative pathname in a system-dependent way. If parent is the empty abstract pathname then the new File instance is created by converting child into an abstract pathname and resolving the result against a system-dependent default directory. Otherwise each pathname string is converted into an abstract pathname and the child abstract pathname is resolved against the parent. param parent The parent abstract pathname param child The child pathname string throws NullPointerException If child is null if (child == null) { throw new NullPointerException(); } if (parent != null) { if (parent.path.equals("")) { this.path = fs.resolve(fs.getDefaultParent(), fs.normalize(child)); } else { this.path = fs.resolve(parent.path, fs.normalize(child)); } } else { this.path = fs.normalize(child); } this.prefixLength = fs.prefixLength(this.path);
public File(URI uri) Creates a new File instance by converting the given file: URI into an abstract pathname. The exact form of a file: URI is system-dependent, hence the transformation performed by this constructor is also system-dependent. For a given abstract pathname f it is guaranteed that new File( f.{@link #toURI() toURI}()).equals( f.{@link #getAbsoluteFile() getAbsoluteFile}()) so long as the original abstract pathname, the URI, and the new abstract pathname are all created in (possibly different invocations of) the same Java virtual machine. This relationship typically does not hold, however, when a file: URI that is created in a virtual machine on one operating system is converted into an abstract pathname in a virtual machine on a different operating system. param uri An absolute, hierarchical URI with a scheme equal to "file", a non-empty path component, and undefined authority, query, and fragment components throws NullPointerException If uri is null throws IllegalArgumentException If the preconditions on the parameter do not hold see #toURI() see java.net.URI since 1.4 // Check our many preconditions if (!uri.isAbsolute()) throw new IllegalArgumentException("URI is not absolute"); if (uri.isOpaque()) throw new IllegalArgumentException("URI is not hierarchical"); String scheme = uri.getScheme(); if ((scheme == null) || !scheme.equalsIgnoreCase("file")) throw new IllegalArgumentException("URI scheme is not \"file\""); if (uri.getAuthority() != null) throw new IllegalArgumentException("URI has an authority component"); if (uri.getFragment() != null) throw new IllegalArgumentException("URI has a fragment component"); if (uri.getQuery() != null) throw new IllegalArgumentException("URI has a query component"); String p = uri.getPath(); if (p.equals("")) throw new IllegalArgumentException("URI path component is empty"); // Okay, now initialize p = fs.fromURIPath(p); if (File.separatorChar != '/") p = p.replace('/", File.separatorChar); this.path = fs.normalize(p); this.prefixLength = fs.prefixLength(this.path);

Methods Summary
public boolean	canExecute() Tests whether the application can execute the file denoted by this abstract pathname. return true if and only if the abstract pathname exists and the application is allowed to execute the file throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkExec(java.lang.String)} method denies execute access to the file since 1.6 SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkExec(path); } return fs.checkAccess(this, FileSystem.ACCESS_EXECUTE);
public boolean	canRead() Tests whether the application can read the file denoted by this abstract pathname. return true if and only if the file specified by this abstract pathname exists and can be read by the application; false otherwise throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkRead(java.lang.String)} method denies read access to the file SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkRead(path); } return fs.checkAccess(this, FileSystem.ACCESS_READ);
public boolean	canWrite() Tests whether the application can modify the file denoted by this abstract pathname. return true if and only if the file system actually contains a file denoted by this abstract pathname and the application is allowed to write to the file; false otherwise. throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkWrite(java.lang.String)} method denies write access to the file SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkWrite(path); } return fs.checkAccess(this, FileSystem.ACCESS_WRITE);
private static boolean	checkAndCreate(java.lang.String filename, java.lang.SecurityManager sm) if (sm != null) { try { sm.checkWrite(filename); } catch (AccessControlException x) { /* Throwing the original AccessControlException could disclose the location of the default temporary directory, so we re-throw a more innocuous SecurityException */ throw new SecurityException("Unable to create temporary file"); } } return fs.createFileExclusively(filename);
public int	compareTo(java.io.File pathname) Compares two abstract pathnames lexicographically. The ordering defined by this method depends upon the underlying system. On UNIX systems, alphabetic case is significant in comparing pathnames; on Microsoft Windows systems it is not. param pathname The abstract pathname to be compared to this abstract pathname return Zero if the argument is equal to this abstract pathname, a value less than zero if this abstract pathname is lexicographically less than the argument, or a value greater than zero if this abstract pathname is lexicographically greater than the argument since 1.2 return fs.compare(this, pathname);
public boolean	createNewFile() Atomically creates a new, empty file named by this abstract pathname if and only if a file with this name does not yet exist. The check for the existence of the file and the creation of the file if it does not exist are a single operation that is atomic with respect to all other filesystem activities that might affect the file. Note: this method should not be used for file-locking, as the resulting protocol cannot be made to work reliably. The {@link java.nio.channels.FileLock FileLock} facility should be used instead. return true if the named file does not exist and was successfully created; false if the named file already exists throws IOException If an I/O error occurred throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkWrite(java.lang.String)} method denies write access to the file since 1.2 SecurityManager security = System.getSecurityManager(); if (security != null) security.checkWrite(path); return fs.createFileExclusively(path);
public static java.io.File	createTempFile(java.lang.String prefix, java.lang.String suffix, java.io.File directory) Creates a new empty file in the specified directory, using the given prefix and suffix strings to generate its name. If this method returns successfully then it is guaranteed that: The file denoted by the returned abstract pathname did not exist before this method was invoked, and Neither this method nor any of its variants will return the same abstract pathname again in the current invocation of the virtual machine. This method provides only part of a temporary-file facility. To arrange for a file created by this method to be deleted automatically, use the {@link #deleteOnExit} method. The prefix argument must be at least three characters long. It is recommended that the prefix be a short, meaningful string such as "hjb" or "mail". The suffix argument may be null, in which case the suffix ".tmp" will be used. To create the new file, the prefix and the suffix may first be adjusted to fit the limitations of the underlying platform. If the prefix is too long then it will be truncated, but its first three characters will always be preserved. If the suffix is too long then it too will be truncated, but if it begins with a period character ('.') then the period and the first three characters following it will always be preserved. Once these adjustments have been made the name of the new file will be generated by concatenating the prefix, five or more internally-generated characters, and the suffix. If the directory argument is null then the system-dependent default temporary-file directory will be used. The default temporary-file directory is specified by the system property java.io.tmpdir. On UNIX systems the default value of this property is typically "/tmp" or "/var/tmp"; on Microsoft Windows systems it is typically "C:\\WINNT\\TEMP". A different value may be given to this system property when the Java virtual machine is invoked, but programmatic changes to this property are not guaranteed to have any effect upon the temporary directory used by this method. param prefix The prefix string to be used in generating the file's name; must be at least three characters long param suffix The suffix string to be used in generating the file's name; may be null, in which case the suffix ".tmp" will be used param directory The directory in which the file is to be created, or null if the default temporary-file directory is to be used return An abstract pathname denoting a newly-created empty file throws IllegalArgumentException If the prefix argument contains fewer than three characters throws IOException If a file could not be created throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkWrite(java.lang.String)} method does not allow a file to be created since 1.2 if (prefix == null) throw new NullPointerException(); if (prefix.length() < 3) throw new IllegalArgumentException("Prefix string too short"); String s = (suffix == null) ? ".tmp" : suffix; synchronized (tmpFileLock) { if (directory == null) { String tmpDir = getTempDir(); directory = new File(tmpDir, fs.prefixLength(tmpDir)); } SecurityManager sm = System.getSecurityManager(); File f; do { f = generateFile(prefix, s, directory); } while (!checkAndCreate(f.getPath(), sm)); return f; }
public static java.io.File	createTempFile(java.lang.String prefix, java.lang.String suffix) Creates an empty file in the default temporary-file directory, using the given prefix and suffix to generate its name. Invoking this method is equivalent to invoking {@link #createTempFile(java.lang.String, java.lang.String, java.io.File) createTempFile(prefix, suffix, null)}. param prefix The prefix string to be used in generating the file's name; must be at least three characters long param suffix The suffix string to be used in generating the file's name; may be null, in which case the suffix ".tmp" will be used return An abstract pathname denoting a newly-created empty file throws IllegalArgumentException If the prefix argument contains fewer than three characters throws IOException If a file could not be created throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkWrite(java.lang.String)} method does not allow a file to be created since 1.2 return createTempFile(prefix, suffix, null);
public boolean	delete() Deletes the file or directory denoted by this abstract pathname. If this pathname denotes a directory, then the directory must be empty in order to be deleted. return true if and only if the file or directory is successfully deleted; false otherwise throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkDelete} method denies delete access to the file SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkDelete(path); } return fs.delete(this);
public void	deleteOnExit() Requests that the file or directory denoted by this abstract pathname be deleted when the virtual machine terminates. Files (or directories) are deleted in the reverse order that they are registered. Invoking this method to delete a file or directory that is already registered for deletion has no effect. Deletion will be attempted only for normal termination of the virtual machine, as defined by the Java Language Specification. Once deletion has been requested, it is not possible to cancel the request. This method should therefore be used with care. Note: this method should not be used for file-locking, as the resulting protocol cannot be made to work reliably. The {@link java.nio.channels.FileLock FileLock} facility should be used instead. throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkDelete} method denies delete access to the file see #delete since 1.2 SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkDelete(path); } DeleteOnExitHook.add(path);
public boolean	equals(java.lang.Object obj) Tests this abstract pathname for equality with the given object. Returns true if and only if the argument is not null and is an abstract pathname that denotes the same file or directory as this abstract pathname. Whether or not two abstract pathnames are equal depends upon the underlying system. On UNIX systems, alphabetic case is significant in comparing pathnames; on Microsoft Windows systems it is not. param obj The object to be compared with this abstract pathname return true if and only if the objects are the same; false otherwise if ((obj != null) && (obj instanceof File)) { return compareTo((File)obj) == 0; } return false;
public boolean	exists() Tests whether the file or directory denoted by this abstract pathname exists. return true if and only if the file or directory denoted by this abstract pathname exists; false otherwise throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkRead(java.lang.String)} method denies read access to the file or directory SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkRead(path); } return ((fs.getBooleanAttributes(this) & FileSystem.BA_EXISTS) != 0);
private static java.io.File	generateFile(java.lang.String prefix, java.lang.String suffix, java.io.File dir) /* Protected by tmpFileLock */ if (counter == -1) { counter = new Random().nextInt() & 0xffff; } counter++; return new File(dir, prefix + Integer.toString(counter) + suffix);
public java.io.File	getAbsoluteFile() Returns the absolute form of this abstract pathname. Equivalent to new File(this.{@link #getAbsolutePath}). return The absolute abstract pathname denoting the same file or directory as this abstract pathname throws SecurityException If a required system property value cannot be accessed. since 1.2 String absPath = getAbsolutePath(); return new File(absPath, fs.prefixLength(absPath));
public java.lang.String	getAbsolutePath() Returns the absolute pathname string of this abstract pathname. If this abstract pathname is already absolute, then the pathname string is simply returned as if by the {@link #getPath} method. If this abstract pathname is the empty abstract pathname then the pathname string of the current user directory, which is named by the system property user.dir, is returned. Otherwise this pathname is resolved in a system-dependent way. On UNIX systems, a relative pathname is made absolute by resolving it against the current user directory. On Microsoft Windows systems, a relative pathname is made absolute by resolving it against the current directory of the drive named by the pathname, if any; if not, it is resolved against the current user directory. return The absolute pathname string denoting the same file or directory as this abstract pathname throws SecurityException If a required system property value cannot be accessed. see java.io.File#isAbsolute() return fs.resolve(this);
public java.io.File	getCanonicalFile() Returns the canonical form of this abstract pathname. Equivalent to new File(this.{@link #getCanonicalPath}). return The canonical pathname string denoting the same file or directory as this abstract pathname throws IOException If an I/O error occurs, which is possible because the construction of the canonical pathname may require filesystem queries throws SecurityException If a required system property value cannot be accessed, or if a security manager exists and its {@link java.lang.SecurityManager#checkRead} method denies read access to the file since 1.2 String canonPath = getCanonicalPath(); return new File(canonPath, fs.prefixLength(canonPath));
public java.lang.String	getCanonicalPath() Returns the canonical pathname string of this abstract pathname. A canonical pathname is both absolute and unique. The precise definition of canonical form is system-dependent. This method first converts this pathname to absolute form if necessary, as if by invoking the {@link #getAbsolutePath} method, and then maps it to its unique form in a system-dependent way. This typically involves removing redundant names such as "." and ".." from the pathname, resolving symbolic links (on UNIX platforms), and converting drive letters to a standard case (on Microsoft Windows platforms). Every pathname that denotes an existing file or directory has a unique canonical form. Every pathname that denotes a nonexistent file or directory also has a unique canonical form. The canonical form of the pathname of a nonexistent file or directory may be different from the canonical form of the same pathname after the file or directory is created. Similarly, the canonical form of the pathname of an existing file or directory may be different from the canonical form of the same pathname after the file or directory is deleted. return The canonical pathname string denoting the same file or directory as this abstract pathname throws IOException If an I/O error occurs, which is possible because the construction of the canonical pathname may require filesystem queries throws SecurityException If a required system property value cannot be accessed, or if a security manager exists and its {@link java.lang.SecurityManager#checkRead} method denies read access to the file since JDK1.1 return fs.canonicalize(fs.resolve(this));
public long	getFreeSpace() Returns the number of unallocated bytes in the partition named by this abstract path name. The returned number of unallocated bytes is a hint, but not a guarantee, that it is possible to use most or any of these bytes. The number of unallocated bytes is most likely to be accurate immediately after this call. It is likely to be made inaccurate by any external I/O operations including those made on the system outside of this virtual machine. This method makes no guarantee that write operations to this file system will succeed. return The number of unallocated bytes on the partition 0L if the abstract pathname does not name a partition. This value will be less than or equal to the total file system size returned by {@link #getTotalSpace}. throws SecurityException If a security manager has been installed and it denies {@link RuntimePermission}("getFileSystemAttributes") or its {@link SecurityManager#checkRead(String)} method denies read access to the file named by this abstract pathname since 1.6 SecurityManager sm = System.getSecurityManager(); if (sm != null) { sm.checkPermission(new RuntimePermission("getFileSystemAttributes")); sm.checkRead(path); } return fs.getSpace(this, FileSystem.SPACE_FREE);
public java.lang.String	getName() Returns the name of the file or directory denoted by this abstract pathname. This is just the last name in the pathname's name sequence. If the pathname's name sequence is empty, then the empty string is returned. return The name of the file or directory denoted by this abstract pathname, or the empty string if this pathname's name sequence is empty int index = path.lastIndexOf(separatorChar); if (index < prefixLength) return path.substring(prefixLength); return path.substring(index + 1);
public java.lang.String	getParent() Returns the pathname string of this abstract pathname's parent, or null if this pathname does not name a parent directory. The parent of an abstract pathname consists of the pathname's prefix, if any, and each name in the pathname's name sequence except for the last. If the name sequence is empty then the pathname does not name a parent directory. return The pathname string of the parent directory named by this abstract pathname, or null if this pathname does not name a parent int index = path.lastIndexOf(separatorChar); if (index < prefixLength) { if ((prefixLength > 0) && (path.length() > prefixLength)) return path.substring(0, prefixLength); return null; } return path.substring(0, index);
public java.io.File	getParentFile() Returns the abstract pathname of this abstract pathname's parent, or null if this pathname does not name a parent directory. The parent of an abstract pathname consists of the pathname's prefix, if any, and each name in the pathname's name sequence except for the last. If the name sequence is empty then the pathname does not name a parent directory. return The abstract pathname of the parent directory named by this abstract pathname, or null if this pathname does not name a parent since 1.2 String p = this.getParent(); if (p == null) return null; return new File(p, this.prefixLength);
public java.lang.String	getPath() Converts this abstract pathname into a pathname string. The resulting string uses the {@link #separator default name-separator character} to separate the names in the name sequence. return The string form of this abstract pathname return path;
int	getPrefixLength() Returns the length of this abstract pathname's prefix. For use by FileSystem classes. return prefixLength;
private static java.lang.String	getTempDir() if (tmpdir == null) { GetPropertyAction a = new GetPropertyAction("java.io.tmpdir"); tmpdir = ((String) AccessController.doPrivileged(a)); tmpdir = fs.normalize(tmpdir); } return tmpdir;
public long	getTotalSpace() Returns the size of the partition named by this abstract pathname. return The size, in bytes, of the partition or 0L if this abstract pathname does not name a partition throws SecurityException If a security manager has been installed and it denies {@link RuntimePermission}("getFileSystemAttributes") or its {@link SecurityManager#checkRead(String)} method denies read access to the file named by this abstract pathname since 1.6 SecurityManager sm = System.getSecurityManager(); if (sm != null) { sm.checkPermission(new RuntimePermission("getFileSystemAttributes")); sm.checkRead(path); } return fs.getSpace(this, FileSystem.SPACE_TOTAL);
public long	getUsableSpace() Returns the number of bytes available to this virtual machine on the partition named by this abstract pathname. When possible, this method checks for write permissions and other operating system restrictions and will therefore usually provide a more accurate estimate of how much new data can actually be written than {@link #getFreeSpace}. The returned number of available bytes is a hint, but not a guarantee, that it is possible to use most or any of these bytes. The number of unallocated bytes is most likely to be accurate immediately after this call. It is likely to be made inaccurate by any external I/O operations including those made on the system outside of this virtual machine. This method makes no guarantee that write operations to this file system will succeed. return The number of available bytes on the partition or 0L if the abstract pathname does not name a partition. On systems where this information is not available, this method will be equivalent to a call to {@link #getFreeSpace}. throws SecurityException If a security manager has been installed and it denies {@link RuntimePermission}("getFileSystemAttributes") or its {@link SecurityManager#checkRead(String)} method denies read access to the file named by this abstract pathname since 1.6 SecurityManager sm = System.getSecurityManager(); if (sm != null) { sm.checkPermission(new RuntimePermission("getFileSystemAttributes")); sm.checkRead(path); } return fs.getSpace(this, FileSystem.SPACE_USABLE);
public int	hashCode() Computes a hash code for this abstract pathname. Because equality of abstract pathnames is inherently system-dependent, so is the computation of their hash codes. On UNIX systems, the hash code of an abstract pathname is equal to the exclusive or of the hash code of its pathname string and the decimal value 1234321. On Microsoft Windows systems, the hash code is equal to the exclusive or of the hash code of its pathname string converted to lower case and the decimal value 1234321. Locale is not taken into account on lowercasing the pathname string. return A hash code for this abstract pathname return fs.hashCode(this);
public boolean	isAbsolute() Tests whether this abstract pathname is absolute. The definition of absolute pathname is system dependent. On UNIX systems, a pathname is absolute if its prefix is "/". On Microsoft Windows systems, a pathname is absolute if its prefix is a drive specifier followed by "\\", or if its prefix is "\\\\". return true if this abstract pathname is absolute, false otherwise return fs.isAbsolute(this);
public boolean	isDirectory() Tests whether the file denoted by this abstract pathname is a directory. return true if and only if the file denoted by this abstract pathname exists and is a directory; false otherwise throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkRead(java.lang.String)} method denies read access to the file SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkRead(path); } return ((fs.getBooleanAttributes(this) & FileSystem.BA_DIRECTORY) != 0);
public boolean	isFile() Tests whether the file denoted by this abstract pathname is a normal file. A file is normal if it is not a directory and, in addition, satisfies other system-dependent criteria. Any non-directory file created by a Java application is guaranteed to be a normal file. return true if and only if the file denoted by this abstract pathname exists and is a normal file; false otherwise throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkRead(java.lang.String)} method denies read access to the file SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkRead(path); } return ((fs.getBooleanAttributes(this) & FileSystem.BA_REGULAR) != 0);
public boolean	isHidden() Tests whether the file named by this abstract pathname is a hidden file. The exact definition of hidden is system-dependent. On UNIX systems, a file is considered to be hidden if its name begins with a period character ('.'). On Microsoft Windows systems, a file is considered to be hidden if it has been marked as such in the filesystem. return true if and only if the file denoted by this abstract pathname is hidden according to the conventions of the underlying platform throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkRead(java.lang.String)} method denies read access to the file since 1.2 SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkRead(path); } return ((fs.getBooleanAttributes(this) & FileSystem.BA_HIDDEN) != 0);
public long	lastModified() Returns the time that the file denoted by this abstract pathname was last modified. return A long value representing the time the file was last modified, measured in milliseconds since the epoch (00:00:00 GMT, January 1, 1970), or 0L if the file does not exist or if an I/O error occurs throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkRead(java.lang.String)} method denies read access to the file SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkRead(path); } return fs.getLastModifiedTime(this);
public long	length() Returns the length of the file denoted by this abstract pathname. The return value is unspecified if this pathname denotes a directory. return The length, in bytes, of the file denoted by this abstract pathname, or 0L if the file does not exist. Some operating systems may return 0L for pathnames denoting system-dependent entities such as devices or pipes. throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkRead(java.lang.String)} method denies read access to the file SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkRead(path); } return fs.getLength(this);
public java.lang.String[]	list() Returns an array of strings naming the files and directories in the directory denoted by this abstract pathname. If this abstract pathname does not denote a directory, then this method returns null. Otherwise an array of strings is returned, one for each file or directory in the directory. Names denoting the directory itself and the directory's parent directory are not included in the result. Each string is a file name rather than a complete path. There is no guarantee that the name strings in the resulting array will appear in any specific order; they are not, in particular, guaranteed to appear in alphabetical order. return An array of strings naming the files and directories in the directory denoted by this abstract pathname. The array will be empty if the directory is empty. Returns null if this abstract pathname does not denote a directory, or if an I/O error occurs. throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkRead(java.lang.String)} method denies read access to the directory SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkRead(path); } return fs.list(this);
public java.lang.String[]	list(java.io.FilenameFilter filter) Returns an array of strings naming the files and directories in the directory denoted by this abstract pathname that satisfy the specified filter. The behavior of this method is the same as that of the {@link #list()} method, except that the strings in the returned array must satisfy the filter. If the given filter is null then all names are accepted. Otherwise, a name satisfies the filter if and only if the value true results when the {@link FilenameFilter#accept} method of the filter is invoked on this abstract pathname and the name of a file or directory in the directory that it denotes. param filter A filename filter return An array of strings naming the files and directories in the directory denoted by this abstract pathname that were accepted by the given filter. The array will be empty if the directory is empty or if no names were accepted by the filter. Returns null if this abstract pathname does not denote a directory, or if an I/O error occurs. throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkRead(java.lang.String)} method denies read access to the directory String names[] = list(); if ((names == null) || (filter == null)) { return names; } ArrayList v = new ArrayList(); for (int i = 0 ; i < names.length ; i++) { if (filter.accept(this, names[i])) { v.add(names[i]); } } return (String[])(v.toArray(new String[v.size()]));
public java.io.File[]	listFiles() Returns an array of abstract pathnames denoting the files in the directory denoted by this abstract pathname. If this abstract pathname does not denote a directory, then this method returns null. Otherwise an array of File objects is returned, one for each file or directory in the directory. Pathnames denoting the directory itself and the directory's parent directory are not included in the result. Each resulting abstract pathname is constructed from this abstract pathname using the {@link #File(java.io.File, java.lang.String) File(File, String)} constructor. Therefore if this pathname is absolute then each resulting pathname is absolute; if this pathname is relative then each resulting pathname will be relative to the same directory. There is no guarantee that the name strings in the resulting array will appear in any specific order; they are not, in particular, guaranteed to appear in alphabetical order. return An array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname. The array will be empty if the directory is empty. Returns null if this abstract pathname does not denote a directory, or if an I/O error occurs. throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkRead(java.lang.String)} method denies read access to the directory since 1.2 String[] ss = list(); if (ss == null) return null; int n = ss.length; File[] fs = new File[n]; for (int i = 0; i < n; i++) { fs[i] = new File(ss[i], this); } return fs;
public java.io.File[]	listFiles(java.io.FilenameFilter filter) Returns an array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname that satisfy the specified filter. The behavior of this method is the same as that of the {@link #listFiles()} method, except that the pathnames in the returned array must satisfy the filter. If the given filter is null then all pathnames are accepted. Otherwise, a pathname satisfies the filter if and only if the value true results when the {@link FilenameFilter#accept} method of the filter is invoked on this abstract pathname and the name of a file or directory in the directory that it denotes. param filter A filename filter return An array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname. The array will be empty if the directory is empty. Returns null if this abstract pathname does not denote a directory, or if an I/O error occurs. throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkRead(java.lang.String)} method denies read access to the directory since 1.2 String ss[] = list(); if (ss == null) return null; ArrayList v = new ArrayList(); for (int i = 0 ; i < ss.length ; i++) { if ((filter == null) || filter.accept(this, ss[i])) { v.add(new File(ss[i], this)); } } return (File[])(v.toArray(new File[v.size()]));
public java.io.File[]	listFiles(java.io.FileFilter filter) Returns an array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname that satisfy the specified filter. The behavior of this method is the same as that of the {@link #listFiles()} method, except that the pathnames in the returned array must satisfy the filter. If the given filter is null then all pathnames are accepted. Otherwise, a pathname satisfies the filter if and only if the value true results when the {@link FileFilter#accept(java.io.File)} method of the filter is invoked on the pathname. param filter A file filter return An array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname. The array will be empty if the directory is empty. Returns null if this abstract pathname does not denote a directory, or if an I/O error occurs. throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkRead(java.lang.String)} method denies read access to the directory since 1.2 String ss[] = list(); if (ss == null) return null; ArrayList v = new ArrayList(); for (int i = 0 ; i < ss.length ; i++) { File f = new File(ss[i], this); if ((filter == null) || filter.accept(f)) { v.add(f); } } return (File[])(v.toArray(new File[v.size()]));
public static java.io.File[]	listRoots() List the available filesystem roots. A particular Java platform may support zero or more hierarchically-organized file systems. Each file system has a root directory from which all other files in that file system can be reached. Windows platforms, for example, have a root directory for each active drive; UNIX platforms have a single root directory, namely "/". The set of available filesystem roots is affected by various system-level operations such as the insertion or ejection of removable media and the disconnecting or unmounting of physical or virtual disk drives. This method returns an array of File objects that denote the root directories of the available filesystem roots. It is guaranteed that the canonical pathname of any file physically present on the local machine will begin with one of the roots returned by this method. The canonical pathname of a file that resides on some other machine and is accessed via a remote-filesystem protocol such as SMB or NFS may or may not begin with one of the roots returned by this method. If the pathname of a remote file is syntactically indistinguishable from the pathname of a local file then it will begin with one of the roots returned by this method. Thus, for example, File objects denoting the root directories of the mapped network drives of a Windows platform will be returned by this method, while File objects containing UNC pathnames will not be returned by this method. Unlike most methods in this class, this method does not throw security exceptions. If a security manager exists and its {@link java.lang.SecurityManager#checkRead(java.lang.String)} method denies read access to a particular root directory, then that directory will not appear in the result. return An array of File objects denoting the available filesystem roots, or null if the set of roots could not be determined. The array will be empty if there are no filesystem roots. since 1.2 return fs.listRoots();
public boolean	mkdir() Creates the directory named by this abstract pathname. return true if and only if the directory was created; false otherwise throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkWrite(java.lang.String)} method does not permit the named directory to be created SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkWrite(path); } return fs.createDirectory(this);
public boolean	mkdirs() Creates the directory named by this abstract pathname, including any necessary but nonexistent parent directories. Note that if this operation fails it may have succeeded in creating some of the necessary parent directories. return true if and only if the directory was created, along with all necessary parent directories; false otherwise throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkRead(java.lang.String)} method does not permit verification of the existence of the named directory and all necessary parent directories; or if the {@link java.lang.SecurityManager#checkWrite(java.lang.String)} method does not permit the named directory and all necessary parent directories to be created if (exists()) { return false; } if (mkdir()) { return true; } File canonFile = null; try { canonFile = getCanonicalFile(); } catch (IOException e) { return false; } File parent = canonFile.getParentFile(); return (parent != null && (parent.mkdirs() || parent.exists()) && canonFile.mkdir());
private synchronized void	readObject(java.io.ObjectInputStream s) readObject is called to restore this filename. The original separator character is read. If it is different than the separator character on this system, then the old separator is replaced by the local separator. s.defaultReadObject(); char sep = s.readChar(); // read the previous separator char if (sep != separatorChar) this.path = this.path.replace(sep, separatorChar); this.path = fs.normalize(this.path); this.prefixLength = fs.prefixLength(this.path);
public boolean	renameTo(java.io.File dest) Renames the file denoted by this abstract pathname. Many aspects of the behavior of this method are inherently platform-dependent: The rename operation might not be able to move a file from one filesystem to another, it might not be atomic, and it might not succeed if a file with the destination abstract pathname already exists. The return value should always be checked to make sure that the rename operation was successful. param dest The new abstract pathname for the named file return true if and only if the renaming succeeded; false otherwise throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkWrite(java.lang.String)} method denies write access to either the old or new pathnames throws NullPointerException If parameter dest is null SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkWrite(path); security.checkWrite(dest.path); } return fs.rename(this, dest);
public boolean	setExecutable(boolean executable, boolean ownerOnly) Sets the owner's or everybody's execute permission for this abstract pathname. param executable If true, sets the access permission to allow execute operations; if false to disallow execute operations param ownerOnly If true, the execute permission applies only to the owner's execute permission; otherwise, it applies to everybody. If the underlying file system can not distinguish the owner's execute permission from that of others, then the permission will apply to everybody, regardless of this value. return true if and only if the operation succeeded. The operation will fail if the user does not have permission to change the access permissions of this abstract pathname. If executable is false and the underlying file system does not implement an execute permission, then the operation will fail. throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkWrite(java.lang.String)} method denies write access to the file since 1.6 SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkWrite(path); } return fs.setPermission(this, FileSystem.ACCESS_EXECUTE, executable, ownerOnly);
public boolean	setExecutable(boolean executable) A convenience method to set the owner's execute permission for this abstract pathname. An invocation of this method of the form file.setExcutable(arg) behaves in exactly the same way as the invocation file.setExecutable(arg, true) param executable If true, sets the access permission to allow execute operations; if false to disallow execute operations return true if and only if the operation succeeded. The operation will fail if the user does not have permission to change the access permissions of this abstract pathname. If executable is false and the underlying file system does not implement an excute permission, then the operation will fail. throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkWrite(java.lang.String)} method denies write access to the file since 1.6 return setExecutable(executable, true);
public boolean	setLastModified(long time) Sets the last-modified time of the file or directory named by this abstract pathname. All platforms support file-modification times to the nearest second, but some provide more precision. The argument will be truncated to fit the supported precision. If the operation succeeds and no intervening operations on the file take place, then the next invocation of the {@link #lastModified} method will return the (possibly truncated) time argument that was passed to this method. param time The new last-modified time, measured in milliseconds since the epoch (00:00:00 GMT, January 1, 1970) return true if and only if the operation succeeded; false otherwise throws IllegalArgumentException If the argument is negative throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkWrite(java.lang.String)} method denies write access to the named file since 1.2 if (time < 0) throw new IllegalArgumentException("Negative time"); SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkWrite(path); } return fs.setLastModifiedTime(this, time);
public boolean	setReadOnly() Marks the file or directory named by this abstract pathname so that only read operations are allowed. After invoking this method the file or directory is guaranteed not to change until it is either deleted or marked to allow write access. Whether or not a read-only file or directory may be deleted depends upon the underlying system. return true if and only if the operation succeeded; false otherwise throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkWrite(java.lang.String)} method denies write access to the named file since 1.2 SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkWrite(path); } return fs.setReadOnly(this);
public boolean	setReadable(boolean readable, boolean ownerOnly) Sets the owner's or everybody's read permission for this abstract pathname. param readable If true, sets the access permission to allow read operations; if false to disallow read operations param ownerOnly If true, the read permission applies only to the owner's read permission; otherwise, it applies to everybody. If the underlying file system can not distinguish the owner's read permission from that of others, then the permission will apply to everybody, regardless of this value. return true if and only if the operation succeeded. The operation will fail if the user does not have permission to change the access permissions of this abstract pathname. If readable is false and the underlying file system does not implement a read permission, then the operation will fail. throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkWrite(java.lang.String)} method denies write access to the file since 1.6 SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkWrite(path); } return fs.setPermission(this, FileSystem.ACCESS_READ, readable, ownerOnly);
public boolean	setReadable(boolean readable) A convenience method to set the owner's read permission for this abstract pathname. An invocation of this method of the form file.setReadable(arg) behaves in exactly the same way as the invocation file.setReadable(arg, true) param readable If true, sets the access permission to allow read operations; if false to disallow read operations return true if and only if the operation succeeded. The operation will fail if the user does not have permission to change the access permissions of this abstract pathname. If readable is false and the underlying file system does not implement a read permission, then the operation will fail. throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkWrite(java.lang.String)} method denies write access to the file since 1.6 return setReadable(readable, true);
public boolean	setWritable(boolean writable, boolean ownerOnly) Sets the owner's or everybody's write permission for this abstract pathname. param writable If true, sets the access permission to allow write operations; if false to disallow write operations param ownerOnly If true, the write permission applies only to the owner's write permission; otherwise, it applies to everybody. If the underlying file system can not distinguish the owner's write permission from that of others, then the permission will apply to everybody, regardless of this value. return true if and only if the operation succeeded. The operation will fail if the user does not have permission to change the access permissions of this abstract pathname. throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkWrite(java.lang.String)} method denies write access to the named file since 1.6 SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkWrite(path); } return fs.setPermission(this, FileSystem.ACCESS_WRITE, writable, ownerOnly);
public boolean	setWritable(boolean writable) A convenience method to set the owner's write permission for this abstract pathname. An invocation of this method of the form file.setWritable(arg) behaves in exactly the same way as the invocation file.setWritable(arg, true) param writable If true, sets the access permission to allow write operations; if false to disallow write operations return true if and only if the operation succeeded. The operation will fail if the user does not have permission to change the access permissions of this abstract pathname. throws SecurityException If a security manager exists and its {@link java.lang.SecurityManager#checkWrite(java.lang.String)} method denies write access to the file since 1.6 return setWritable(writable, true);
private static java.lang.String	slashify(java.lang.String path, boolean isDirectory) String p = path; if (File.separatorChar != '/") p = p.replace(File.separatorChar, '/"); if (!p.startsWith("/")) p = "/" + p; if (!p.endsWith("/") && isDirectory) p = p + "/"; return p;
public java.lang.String	toString() Returns the pathname string of this abstract pathname. This is just the string returned by the {@link #getPath} method. return The string form of this abstract pathname return getPath();
public java.net.URI	toURI() Constructs a file: URI that represents this abstract pathname. The exact form of the URI is system-dependent. If it can be determined that the file denoted by this abstract pathname is a directory, then the resulting URI will end with a slash. For a given abstract pathname f, it is guaranteed that new {@link #File(java.net.URI) File}( f.toURI()).equals( f.{@link #getAbsoluteFile() getAbsoluteFile}()) so long as the original abstract pathname, the URI, and the new abstract pathname are all created in (possibly different invocations of) the same Java virtual machine. Due to the system-dependent nature of abstract pathnames, however, this relationship typically does not hold when a file: URI that is created in a virtual machine on one operating system is converted into an abstract pathname in a virtual machine on a different operating system. return An absolute, hierarchical URI with a scheme equal to "file", a path representing this abstract pathname, and undefined authority, query, and fragment components throws SecurityException If a required system property value cannot be accessed. see #File(java.net.URI) see java.net.URI see java.net.URI#toURL() since 1.4 try { File f = getAbsoluteFile(); String sp = slashify(f.getPath(), f.isDirectory()); if (sp.startsWith("//")) sp = "//" + sp; return new URI("file", null, sp, null); } catch (URISyntaxException x) { throw new Error(x); // Can't happen }
public java.net.URL	toURL() Converts this abstract pathname into a file: URL. The exact form of the URL is system-dependent. If it can be determined that the file denoted by this abstract pathname is a directory, then the resulting URL will end with a slash. return A URL object representing the equivalent file URL throws MalformedURLException If the path cannot be parsed as a URL see #toURI() see java.net.URI see java.net.URI#toURL() see java.net.URL since 1.2 deprecated This method does not automatically escape characters that are illegal in URLs. It is recommended that new code convert an abstract pathname into a URL by first converting it into a URI, via the {@link #toURI() toURI} method, and then converting the URI into a URL via the {@link java.net.URI#toURL() URI.toURL} method. return new URL("file", "", slashify(getAbsolutePath(), isDirectory()));
private synchronized void	writeObject(java.io.ObjectOutputStream s) WriteObject is called to save this filename. The separator character is saved also so it can be replaced in case the path is reconstituted on a different host type. serialData Default fields followed by separator character. s.defaultWriteObject(); s.writeChar(this.separatorChar); // Add the separator character