org.objectledge.filesystem.impl
Class ReadOnlyFileSystemProvider

java.lang.Object
  org.objectledge.filesystem.impl.ReadOnlyFileSystemProvider

All Implemented Interfaces:

FileSystemProvider

Direct Known Subclasses:

ClasspathFileSystemProvider

public abstract class ReadOnlyFileSystemProvider
extends Object
implements FileSystemProvider

A base class for read only FileSystem backend implemetations.

Version:

$Id: ReadOnlyFileSystemProvider.java,v 1.21 2006/02/08 18:22:33 zwierzem Exp $

Author:

Rafal Krzewski

Field Summary

private Map<String,Object>	directoryTree The directory tree.
private Map<String,Long>	lengths The file listing.
private Map<String,Object>	listing The file listing.
static String	LISTING_ENCODING the character encoding used in file listings.
static String[]	LISTING_LOCATION locations of the file listings, in order of precedence.
protected String	name Providers's name.
private Map<String,Long>	times The file listing.

Constructor Summary

ReadOnlyFileSystemProvider(String name)
Creates an instance of the provider.

Method Summary

boolean	canRead(String path) Checks if the application is allowed to read given file or directory.
boolean	canWrite(String path) Checks if the application is allowed to write given file or directory.
boolean	checkPathChars(String path) Returns true if the given path contains acceptable characters.
boolean	createNewFile(String path) Atomically creates a new, empty file named by this abstract pathname if and only if a file with this name does not yet exist.
void	delete(String path) Deletes a file or directory.
boolean	exists(String path) Checks if the given file or directory exists.
abstract InputStream	getInputStream(String path) Opens an input stream for reading a file.
String	getName() Returns the name of the provider.
OutputStream	getOutputStream(String path, boolean append) Opens an output stream for writing to file.
RandomAccessFile	getRandomAccess(String path, String mode) Returns a RandomAccess interface implementation for accessing the file at arbitrary positions.
boolean	isDirectory(String path) Checks if the given pathname points to a directory.
boolean	isFile(String path) Checks if the given pathname points to an ordinary file.
boolean	isReadOnly() Returns true if the provider is readonly.
long	lastModified(String path) Returns the time of the last modificaion of the specified file.
long	length(String path) Returns the size of the specified file.
Set<String>	list(String dir) Lists the files and directories inside a directory.
void	mkdirs(String path) Creates a directory, and all necceray parent directories.
protected void	processListing(String location, InputStream is) Processes a listing.
protected void	processListings() Processes the liststings at the common locations.
void	rename(String from, String to) Atomically renames a file or directory.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.objectledge.filesystem.FileSystemProvider

getResource

Field Detail

LISTING_LOCATION

public static final String[] LISTING_LOCATION

locations of the file listings, in order of precedence.

LISTING_ENCODING

public static final String LISTING_ENCODING

the character encoding used in file listings.

See Also:

Constant Field Values

name

protected String name

Providers's name.

listing

private Map<String,Object> listing

The file listing.

directoryTree

private Map<String,Object> directoryTree

The directory tree.

times

private Map<String,Long> times

The file listing.

lengths

private Map<String,Long> lengths

The file listing.

Constructor Detail

ReadOnlyFileSystemProvider

public ReadOnlyFileSystemProvider(String name)

Creates an instance of the provider.

Parameters:

name - the name of the provider.

Method Detail

processListings

protected void processListings()
                        throws IOException

Processes the liststings at the common locations.

getInputStream(String) method must be functional at the point of calling this method.

Throws:

IOException - if the listings cannot be processed.

getName

public String getName()

Returns the name of the provider.

Specified by:

getName in interface FileSystemProvider

Returns:

name of the provider.

isReadOnly

public boolean isReadOnly()

Returns true if the provider is readonly.

Specified by:

isReadOnly in interface FileSystemProvider

Returns:

true if the provider is readonly.

processListing

protected void processListing(String location,
                              InputStream is)
                       throws IOException

Processes a listing.

Parameters:

location - the location of the listing

is - the stream used for reading the listing.

Throws:

IOException - if the index file cannot be processed.

checkPathChars

public boolean checkPathChars(String path)

Returns true if the given path contains acceptable characters.

Specified by:

checkPathChars in interface FileSystemProvider

Parameters:

path - the path.

Returns:

true if the given path contains acceptable characters.

exists

public boolean exists(String path)

Checks if the given file or directory exists.

Specified by:

exists in interface FileSystemProvider

Parameters:

path - the path.

Returns:

true if the given file or directory exists.

isFile

public boolean isFile(String path)

Checks if the given pathname points to an ordinary file.

Specified by:

isFile in interface FileSystemProvider

Parameters:

path - the path

Returns:

true if the given pathname points to a directory.

isDirectory

public boolean isDirectory(String path)

Checks if the given pathname points to a directory.

Specified by:

isDirectory in interface FileSystemProvider

Parameters:

path - the path

Returns:

true if the given pathname points to a directory.

canRead

public boolean canRead(String path)

Checks if the application is allowed to read given file or directory.

Specified by:

canRead in interface FileSystemProvider

Parameters:

path - the path.

Returns:

true if the application is allowed to read given file or directory.

canWrite

public boolean canWrite(String path)

Checks if the application is allowed to write given file or directory.

Specified by:

canWrite in interface FileSystemProvider

Parameters:

path - the path.

Returns:

true if the application is allowed to write given file or directory.

list

public Set<String> list(String dir)
                 throws IOException

Lists the files and directories inside a directory.

Specified by:

list in interface FileSystemProvider

Parameters:

dir - the directory.

Returns:

a list of names.

Throws:

IOException - if dir does not exist or is not a directory.

createNewFile

public boolean createNewFile(String path)
                      throws IOException

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.

Specified by:

createNewFile in interface FileSystemProvider

Parameters:

path - the pathname of the file to create.

Returns:

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

Throws:

IOException - if the operation fails.

mkdirs

public void mkdirs(String path)
            throws IOException

Creates a directory, and all necceray parent directories.

Specified by:

mkdirs in interface FileSystemProvider

Parameters:

path - the path.

Throws:

IOException - if the operation fails.

delete

public void delete(String path)
            throws IOException

Deletes a file or directory.

Directories must be empty when being deleted.

Specified by:

delete in interface FileSystemProvider

Parameters:

path - the path.

Throws:

IOException - if the operation fails.

rename

public void rename(String from,
                   String to)
            throws IOException

Atomically renames a file or directory.

Specified by:

rename in interface FileSystemProvider

Parameters:

from - source path.

to - destination path.

Throws:

IOException - if the operation fails.

getInputStream

public abstract InputStream getInputStream(String path)

Opens an input stream for reading a file.

Specified by:

getInputStream in interface FileSystemProvider

Parameters:

path - the path.

Returns:

the InputStream or null if not available.

getOutputStream

public OutputStream getOutputStream(String path,
                                    boolean append)

Opens an output stream for writing to file.

Specified by:

getOutputStream in interface FileSystemProvider

Parameters:

path - the path.

append - true to append, false to truncate.

Returns:

the InputStream or null if not available.

getRandomAccess

public RandomAccessFile getRandomAccess(String path,
                                        String mode)

Returns a RandomAccess interface implementation for accessing the file at arbitrary positions.

Specified by:

getRandomAccess in interface FileSystemProvider

Parameters:

path - the abstract pathname.

mode - the string which defines the opening mode for this random access file, the form of this string is equal to the mode parameter in java.io.RandomAccessFile constructor.

Returns:

an RandomAccess interface implementation, or null if the operation is not supported.

lastModified

public long lastModified(String path)

Returns the time of the last modificaion of the specified file.

The time of the modification is returned as the number of milliseconds sice the epoch (Jan 1 1970), or -1L if the feature is not supported.

Specified by:

lastModified in interface FileSystemProvider

Parameters:

path - the path.

Returns:

the time of last modification of the specified file.

length

public long length(String path)

Returns the size of the specified file.

Specified by:

length in interface FileSystemProvider

Parameters:

path - the path.

Returns:

the size of the file in bytes, of -1 if not supported.