org.itr_rescue.dataGuard.localFileSystem
Class JFMFileSystem

java.lang.Object
  org.itr_rescue.dataGuard.localFileSystem.JFMFileSystem

Direct Known Subclasses:

JFMLocalFilesystem

public abstract class JFMFileSystem
extends java.lang.Object

This class represents the base class for all filesystems.

Author:

sergiu

Constructor Summary

JFMFileSystem()
Empy constructor.

Method Summary

boolean	canRead(JFMFile file) Tests whether the application can read the file denoted by the abstract pathname.
boolean	canWrite(JFMFile file) Tests whether the application can modify to the file denoted by the abstract pathname.
static JFMFileSystem	createFileSystem(java.lang.String name) This method searches through the registered filesystems, loads and returns the requested one.
abstract boolean	createNewFile(JFMFile parent, java.lang.String name) Atomically creates a new, empty file named by the abstract pathname if and only if a file with that name does not yet exist.
boolean	delete(JFMFile file) Deletes the file or directory denoted by the abstract pathname.
boolean	exists(JFMFile file) Tests whether the file or directory denoted by the abstract pathname exists.
abstract JFMFile	getDefaultRootDirectory() The default root directory in the case of filesystems with more than one root directories (like windows)
abstract JFMFile	getFile(java.lang.String pathName) This method returns an JFMFile object based on the pathname provided
abstract char	getPathSeparator() The system-dependent path-separator character.
java.lang.String	getPathSeparatorString() The system-dependent path-separator character, represented as a string for convenience.
static java.util.Hashtable<java.lang.String,java.lang.String>	getRegisteredFilesystems()
JFMFile	getRootDriveFile(JFMFile file) This method returns the root directory of the filesystem of witch the supplied file belongs to.
abstract char	getSeparator() The system-dependent default name-separator character.
java.lang.String	getSeparatorString() The system-dependent default name-separator character, represented as a string for convenience.
abstract JFMFile	getStartDirectory() This method returns the start directory for this filesystem
boolean	isLocal() Tells us if the filesystem is local.
abstract JFMFile[]	listFiles(JFMFile rootFile) Returns an array of abstract pathnames denoting the files in the directory denoted by the abstract pathname.
abstract JFMFile[]	listFiles(JFMFile rootFile, 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.
abstract JFMFile[]	listRoots() List the available filesystem roots.
abstract boolean	mkdir(JFMFile parent, java.lang.String name) Creates the directory named by the abstract pathname denoted by the parameter.
static void	registerFilesystems() This method searches the java path and the plugins directory (a subdirectory of the current directory) for jar's that contain a filesystem plugin.
abstract boolean	setLastModified(JFMFile file, long time) Sets the last-modified time of the file or directory named by the abstract pathname.
abstract boolean	setReadOnly(JFMFile file) Marks the file or directory named by the abstract pathname so that only read operations are allowed.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

JFMFileSystem

public JFMFileSystem()

Empy constructor.

Method Detail

getRegisteredFilesystems

public static java.util.Hashtable<java.lang.String,java.lang.String> getRegisteredFilesystems()

registerFilesystems

public static void registerFilesystems()

This method searches the java path and the plugins directory (a subdirectory of the current directory) for jar's that contain a filesystem plugin. A jar that contains a filesystem plugin, is a jar file that has in its root directory a file named filesystem.xml in which it describes the filesystem class used and its friendly name (to be shown in the menu)

createFileSystem

public static JFMFileSystem createFileSystem(java.lang.String name)

This method searches through the registered filesystems, loads and returns the requested one. Fielsystems are represented in the vector as full qualified names of the class that represents them.

Parameters:

name - The name of the requested filesystem, or null if you accept the default one

Returns:

The requested filesystem instance

getDefaultRootDirectory

public abstract JFMFile getDefaultRootDirectory()

The default root directory in the case of filesystems with more than one root directories (like windows)

Returns:

The default root directory

getPathSeparator

public abstract char getPathSeparator()

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 ';'.

getPathSeparatorString

public java.lang.String getPathSeparatorString()

The system-dependent path-separator character, represented as a string for convenience. This string contains a single character, namely getPathSeparator().

getSeparator

public abstract char getSeparator()

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 '\'.

getSeparatorString

public java.lang.String getSeparatorString()

The system-dependent default name-separator character, represented as a string for convenience. This string contains a single character, namely getSeparator().

listRoots

public abstract JFMFile[] listRoots()

List the available filesystem roots.

See Also:

File.listRoots()

listFiles

public abstract JFMFile[] listFiles(JFMFile rootFile)

Returns an array of abstract pathnames denoting the files in the directory denoted by the 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.

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 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:

java.lang.SecurityException - If a security manager exists and its SecurityManager.checkRead(java.lang.String) method denies read access to the directory

listFiles

public abstract JFMFile[] listFiles(JFMFile rootFile,
                                    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 #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 FilenameFilter.accept(java.io.File, java.lang.String) method of the filter is invoked on this abstract pathname and the name of a file or directory in the directory that it denotes.

Parameters:

filter - A filename filter

Returns:

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:

java.lang.SecurityException - If a security manager exists and its SecurityManager.checkRead(java.lang.String) method denies read access to the directory

mkdir

public abstract boolean mkdir(JFMFile parent,
                              java.lang.String name)

Creates the directory named by the abstract pathname denoted by the parameter.

Parameters:

parent - The parent file that denotes the abstract pathname

name - The name of the new dir

Returns:

true if and only if the directory was created; false otherwise

Throws:

java.lang.SecurityException - If a security manager exists and its SecurityManager.checkWrite(java.lang.String) method does not permit the named directory to be created

delete

public boolean delete(JFMFile file)

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

Parameters:

file - The file that denotes the abstract pathname

Returns:

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

Throws:

java.lang.SecurityException - If a security manager exists and its SecurityManager.checkDelete(java.lang.String) method denies delete access to the file

createNewFile

public abstract boolean createNewFile(JFMFile parent,
                                      java.lang.String name)
                               throws FSException

Atomically creates a new, empty file named by the abstract pathname if and only if a file with that 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.

Parameters:

file - The file that denotes the abstract pathname

Returns:

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

Throws:

FSException - If an filesystem error occurred

java.lang.SecurityException - If a security manager exists and its SecurityManager.checkWrite(java.lang.String) method denies write access to the file

setLastModified

public abstract boolean setLastModified(JFMFile file,
                                        long time)

Sets the last-modified time of the file or directory named by the 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 org.jfm.md.filesystems.JFMFile#lastModified method will return the (possibly truncated) time argument that was passed to this method.

Parameters:

file - The file that denotes the abstract pathname

time - The new last-modified time, measured in milliseconds since the epoch (00:00:00 GMT, January 1, 1970)

Returns:

true if and only if the operation succeeded; false otherwise

Throws:

java.lang.IllegalArgumentException - If the argument is negative

java.lang.SecurityException - If a security manager exists and its SecurityManager.checkWrite(java.lang.String) method denies write access to the named file

setReadOnly

public abstract boolean setReadOnly(JFMFile file)

Marks the file or directory named by the 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.

Parameters:

file - The file that denotes the abstract pathname

Returns:

true if and only if the operation succeeded; false otherwise

Throws:

java.lang.SecurityException - If a security manager exists and its SecurityManager.checkWrite(java.lang.String) method denies write access to the named file

canRead

public boolean canRead(JFMFile file)

Tests whether the application can read the file denoted by the abstract pathname.

Parameters:

file - The file that denotes the abstract pathname

Returns:

true if and only if the file specified by this abstract pathname exists and can be read by the application; false otherwise

Throws:

java.lang.SecurityException - If a security manager exists and its SecurityManager.checkRead(java.lang.String) method denies read access to the file

canWrite

public boolean canWrite(JFMFile file)

Tests whether the application can modify to the file denoted by the abstract pathname.

Parameters:

file - The file that denotes the abstract pathname

Returns:

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:

java.lang.SecurityException - If a security manager exists and its SecurityManager.checkWrite(java.lang.String) method denies write access to the file

exists

public boolean exists(JFMFile file)

Tests whether the file or directory denoted by the abstract pathname exists.

Parameters:

file - The file that denotes the abstract pathname

Returns:

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

Throws:

java.lang.SecurityException - If a security manager exists and its SecurityManager.checkRead(java.lang.String) method denies read access to the file or directory

getRootDriveFile

public JFMFile getRootDriveFile(JFMFile file)

This method returns the root directory of the filesystem of witch the supplied file belongs to. For example:

If the active filesystem is the local filesystem and is an Windows filesystem, this method should return the drive letter of the drive that this file belongs to. On Unix filesystems it will always return '/'. On other filesystems .... it will return whatever the one that imlements it wants to.

Parameters:

file - JFMFile the file whoses root we want to find out.

Returns:

JFMFile the root drive (it cannot be null). It can be the same file that was passed as an argument.

getStartDirectory

public abstract JFMFile getStartDirectory()

This method returns the start directory for this filesystem

Returns:

JFMFile the start directory (for example, on the local filesystem it will be the user directory)

getFile

public abstract JFMFile getFile(java.lang.String pathName)

This method returns an JFMFile object based on the pathname provided

Parameters:

pathName - String

Returns:

JFMFile

isLocal

public boolean isLocal()

Tells us if the filesystem is local. This information may be used for some optimizations in some cases

Returns:

true is the filesystem is a local filesystem (hard-disk) false otherwise (a network one)