ca.uqac.lif.fs

Class Chroot

java.lang.Object

ca.uqac.lif.fs.FilterFileSystem

ca.uqac.lif.fs.Chroot

All Implemented Interfaces:

FileSystem

public class Chroot
extends FilterFileSystem

File system whose root is a sub-directory of another file system. As a result, all absolute paths within the file system are translated as paths relative to this sub-directory within the underlying file system. This creates an environment that resembles the chroot Unix command, hence the name of this class.

Author:

Sylvain Hallé

Nested Class Summary

Nested classes/interfaces inherited from interface ca.uqac.lif.fs.FileSystem

FileSystem.OpenState

Field Summary

Fields

Modifier and Type	Field and Description
protected FilePath	m_root The path in the underlying file system acting as the root of the current file system.

Fields inherited from class ca.uqac.lif.fs.FilterFileSystem

m_fs

Constructor Summary

Constructors

Constructor and Description
Chroot(FileSystem fs, java.lang.String root) Creates a new chroot file system.

Method Summary

Modifier and Type	Method and Description
void	chdir(java.lang.String path) Changes the current directory.
void	delete(java.lang.String path) Deletes a directory and all its contents.
protected java.lang.String	getPath(java.lang.String path) Gets the absolute path corresponding to a path within the file system
boolean	isDirectory(java.lang.String path) Determines if the resource pointed to by a given path corresponds to a directory.
boolean	isFile(java.lang.String path) Determines if the resource pointed to by a given path corresponds to a file.
java.util.List<java.lang.String>	ls() Lists all the files and folders in the current directory.
java.util.List<java.lang.String>	ls(java.lang.String path) Lists all the files and folders in a given directory.
void	mkdir(java.lang.String path) Creates a directory if it does not exist.
void	pushd(java.lang.String path)
java.io.InputStream	readFrom(java.lang.String filename) Reads data from a file.
void	rmdir(java.lang.String path) Deletes a directory and all its contents.
java.io.OutputStream	writeTo(java.lang.String filename) Writes data to a file.

Methods inherited from class ca.uqac.lif.fs.FilterFileSystem

close, getSize, open, popd, pwd

Methods inherited from class java.lang.Object

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

Field Detail

m_root

protected FilePath m_root

The path in the underlying file system acting as the root of the current file system.

Constructor Detail

Chroot

public Chroot(FileSystem fs,
              java.lang.String root)

Creates a new chroot file system.

Parameters:

fs - The underlying file system

root - The directory acting as the root of the current file system

Method Detail

ls

public java.util.List<java.lang.String> ls()
                                    throws FileSystemException

Description copied from interface: FileSystem

Lists all the files and folders in the current directory.

Specified by:

ls in interface FileSystem

Overrides:

ls in class FilterFileSystem

Returns:

The list of files and folders

Throws:

FileSystemException - Thrown if the operation could not be performed for some reason

ls

public java.util.List<java.lang.String> ls(java.lang.String path)
                                    throws FileSystemException

Description copied from interface: FileSystem

Lists all the files and folders in a given directory.

Specified by:

ls in interface FileSystem

Overrides:

ls in class FilterFileSystem

Parameters:

path - The path from which to list files

Returns:

The list of files and folders

Throws:

FileSystemException - Thrown if the operation could not be performed for some reason

isDirectory

public boolean isDirectory(java.lang.String path)
                    throws FileSystemException

Description copied from interface: FileSystem

Determines if the resource pointed to by a given path corresponds to a directory.

Specified by:

isDirectory in interface FileSystem

Overrides:

isDirectory in class FilterFileSystem

Parameters:

path - The path

Returns:

true if the resource exists and is a directory, false otherwise

Throws:

FileSystemException - Thrown if the operation could not be performed for some reason

isFile

public boolean isFile(java.lang.String path)
               throws FileSystemException

Description copied from interface: FileSystem

Determines if the resource pointed to by a given path corresponds to a file.

Specified by:

isFile in interface FileSystem

Overrides:

isFile in class FilterFileSystem

Parameters:

path - The path

Returns:

true if the resource exists and is a file, false otherwise

Throws:

FileSystemException - Thrown if the operation could not be performed for some reason

writeTo

public java.io.OutputStream writeTo(java.lang.String filename)
                             throws FileSystemException

Description copied from interface: FileSystem

Writes data to a file. The method provides an OutputStream to which data can be printed. The data is guaranteed to be committed to the file only when the print stream is closed. Whether data is written before that moment depends on the actual file system implementation.

Specified by:

writeTo in interface FileSystem

Overrides:

writeTo in class FilterFileSystem

Parameters:

filename - The name of the file to which data is to be written

Returns:

An output stream open on the file. If the method successfully returns, it guarantees that this stream is not null

Throws:

FileSystemException - Thrown if the operation could not be performed for some reason

readFrom

public java.io.InputStream readFrom(java.lang.String filename)
                             throws FileSystemException

Description copied from interface: FileSystem

Reads data from a file. The method provides an InputStream from which data can be read. Consumers of this input stream have the responsibility to close the stream after usage.

Specified by:

readFrom in interface FileSystem

Overrides:

readFrom in class FilterFileSystem

Parameters:

filename - The name of the file to which data is to be written

Returns:

A print stream open on the file. If the method successfully returns, it guarantees that this stream is not null

Throws:

FileSystemException - Thrown if the operation could not be performed for some reason

chdir

public void chdir(java.lang.String path)
           throws FileSystemException

Description copied from interface: FileSystem

Changes the current directory.

Specified by:

chdir in interface FileSystem

Overrides:

chdir in class FilterFileSystem

Parameters:

path - The directory to change to. The string can contain a path relative to the current directory.

Throws:

FileSystemException - Thrown if the operation could not be performed for some reason

pushd

public void pushd(java.lang.String path)
           throws FileSystemException

Specified by:

pushd in interface FileSystem

Overrides:

pushd in class FilterFileSystem

Parameters:

path - The directory to change to. The string can contain a path relative to the current directory.

Throws:

FileSystemException - Thrown if the operation could not be performed for some reason

mkdir

public void mkdir(java.lang.String path)
           throws FileSystemException

Description copied from interface: FileSystem

Creates a directory if it does not exist.

Specified by:

mkdir in interface FileSystem

Overrides:

mkdir in class FilterFileSystem

Parameters:

path - The directory to create. The string can contain a path relative to the current directory.

Throws:

FileSystemException - Thrown if the operation could not be performed for some reason

rmdir

public void rmdir(java.lang.String path)
           throws FileSystemException

Description copied from interface: FileSystem

Deletes a directory and all its contents.

Specified by:

rmdir in interface FileSystem

Overrides:

rmdir in class FilterFileSystem

Parameters:

path - The directory to delete

Throws:

FileSystemException - Thrown if the operation could not be performed for some reason

delete

public void delete(java.lang.String path)
            throws FileSystemException

Description copied from interface: FileSystem

Deletes a directory and all its contents.

Specified by:

delete in interface FileSystem

Overrides:

delete in class FilterFileSystem

Parameters:

path - The directory to delete

Throws:

FileSystemException - Thrown if the operation could not be performed for some reason

getPath

protected java.lang.String getPath(java.lang.String path)
                            throws FileSystemException

Gets the absolute path corresponding to a path within the file system

Parameters:

path - The path

Returns:

The absolute path on the local machine

Throws:

FileSystemException - Thrown if the current directory could not be obtained