java.io.File Class Reference

Inheritance diagram for java.io.File:

Public Member Functions
	File (String pathname)
boolean	createNewFile () throws IOException
boolean	delete ()
boolean	exists ()
String	getPath ()
boolean	isDirectory ()
boolean	isFile ()
long	lastModified ()
long	length ()
File []	listFiles ()
long	totalSize ()
long	availableSize ()
String	toString ()

Static Public Attributes
static final String	separator

Detailed Description

A representation of file and directory pathnames.

User interfaces and operating systems use system-dependent pathname strings to name files and directories. This class presents a system-independent view of hierarchical pathnames.

Each name part of a pathname string is separated from the next by a single copy of the default separator character. The default name-separator character is defined by the system property file.separator, and is made available in the public static fields separator and separatorChar of this class.

A pathname must be absolute. An absolute pathname is complete in that no other information is required in order to locate the file that it denotes.

Instances of the File class are immutable; that is, once created, the pathname represented by a File object will never change.

Constructor & Destructor Documentation

File()

java.io.File.File ( String  pathname )

inline

Creates a new File instance with the given absolute pathname string. If the given string is the empty string, then the result is the empty absolute pathname.

Parameters

pathname

A pathname string

Exceptions

NullPointerException

If the pathname argument is null

Member Function Documentation

createNewFile()

boolean java.io.File.createNewFile ( ) throws IOException

inline

Atomically creates a new, empty file named by this absolute 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.

Returns

true if the named file does not exist and was successfully created; false if the named file already exists

Exceptions

IOException

If an I/O error occurred

delete()

boolean java.io.File.delete ( )

inline

Deletes the file or directory denoted by this absolute pathname. If this pathname denotes a directory, then the directory must be empty in order to be deleted.

Returns

true if and only if the file or directory is successfully deleted; false otherwise

exists()

boolean java.io.File.exists ( )

inline

Tests whether the file or directory denoted by this absolute pathname exists.

Returns

true if and only if the file or directory denoted by this absolute pathname exists; false otherwise

getPath()

String java.io.File.getPath ( )

inline

Returns

The string form of this absolute pathname

isDirectory()

boolean java.io.File.isDirectory ( )

inline

Tests whether the file denoted by this absolute pathname is a directory.

Returns

true if and only if the file denoted by this absolute pathname exists and is a directory; false otherwise

isFile()

boolean java.io.File.isFile ( )

inline

Tests whether the file denoted by this absolute 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.

Returns

true if and only if the file denoted by this absolute pathname exists and is a normal file; false otherwise

lastModified()

long java.io.File.lastModified ( )

inline

Returns the time that the file denoted by this absolute pathname was last modified.

Returns

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

length()

long java.io.File.length ( )

inline

Returns the length of the file denoted by this absolute pathname. The return value is unspecified if this pathname denotes a directory.

Returns

The length, in bytes, of the file denoted by this absolute 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.

listFiles()

File [] java.io.File.listFiles ( )

inline

Returns an array of absolute pathnames denoting the files in the directory denoted by this absolute pathname.

If this absolute 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.

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.

Returns

An array of absolute pathnames denoting the files and directories in the directory denoted by this absolute pathname. The array will be empty if the directory is empty. Returns

null 

if this absolute pathname does not denote a directory, or if an I/O error occurs.

toString()

String java.io.File.toString ( )

inline

Returns the pathname string of this absolute pathname. This is just the string returned by the getPath method.

Returns

The string form of this absolute pathname

Member Data Documentation

separator

final String java.io.File.separator

static

Initial value:

= 
                        (Platform.getPlatform() == Platform.PLAT_UNIX) ? "/" : "\\"

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The documentation for this class was generated from the following file:

• src/java/io/File.java