jfilesyslib.filesystems

Class CachingFs

java.lang.Object

jfilesyslib.FileSystem

jfilesyslib.FullFileSystem

jfilesyslib.filesystems.CachingFs

public class CachingFs
extends FullFileSystem

Provides a simple caching mechanism.

Author:

Marc Miltenberger

Constructor Summary

Constructors

Constructor and Description
CachingFs(FileSystem innerFs) Creates a new instance of the caching file system
CachingFs(FileSystem innerFs, int cacheSize) Creates a new instance of the caching file system

Method Summary

Methods

Modifier and Type	Method and Description
void	afterUnmounting() Is called after the file system has been unmounted successfully.
void	beforeMounting(java.lang.String mountPath) Is called directly before the file system is mounted
void	beforeUnmounting() Is called directly before the file system is unmounted
void	close(FileHandle fh) Closes the file handle.
void	createDirectory(java.lang.String path) Creates a new, empty directory.
void	createFile(java.lang.String path) Creates a new (blank) file.
void	createHardLink(java.lang.String source, java.lang.String destination) Creates a hard link at source pointing to destination.
void	createSymbolicLink(java.lang.String from, java.lang.String to) Creates a symbolic link at source pointing to destination.
void	deleteDirectoryRecursively(java.lang.String directory) Deletes a directory recursively.
void	deleteFile(java.lang.String file) Deletes a file or symbolic link.
void	flush(FileHandle fh) Should write all pending data in the cache.
int	getBlockSize() Returns the block size in bytes
EntityInfo	getFileMetaData(java.lang.String path) Returns some meta data about the path.
int	getFilesFreeCount() Returns the number of files which may be created.
java.lang.String	getFileSystemName() Returns the file system name
long	getFreeBlockAvailableCount() Returns the number of free blocks, which are available to the current user.
long	getFreeBlockCount() Returns the number of free blocks.
int	getMaxPathLength() Returns the maximum path length.
long	getTotalBlockCount() Returns the number of total blocks.
int	getTotalFilesCount() Returns the total number of files on the volume.
UnixPermissions	getUnixPermissions(java.lang.String path) Returns the unix permissions
java.lang.String	getVolumeName() Returns the volume name.
int	getVolumeSerialNumber() Returns a volume serial number
WindowsAttributes	getWindowsAttributes(java.lang.String path) Returns the windows attributes.
boolean	isCaseSensitive() Returns true if the pathes are case sensitive
boolean	isCompressed() Returns true if the file system is compressed
boolean	isReadOnly() Returns true if the file system is read only
java.lang.Iterable<EntityInfo>	listDirectory(java.lang.String path) Reads a given directory and returns an iterator.
java.lang.Iterable<ExtendedAttribute>	listExtendedAttributes(java.lang.String path) Lists the extended attributes of a path.
void	lockFile(FileHandle handle, long byteOffset, long length) Locks a file in the specified range for every write access except for the File Handle handle.
FileHandle	openFile(java.lang.String path, boolean read, boolean write) Opens a file.
int	read(FileHandle fh, java.nio.ByteBuffer buffer, long offset) Reads from a file.
void	removeExtendedAttribute(java.lang.String path, java.lang.String attributeName) Sets or adds extended attributes.
void	rename(java.lang.String from, java.lang.String to) Renames a file/directory/symbolic link.
void	setCreationTime(java.lang.String path, long creationTime) Sets the creation time (unix timestamp).
void	setExtendedAttribute(java.lang.String path, ExtendedAttribute attribute) Sets or adds extended attribute.
void	setLastAccessTime(java.lang.String path, long atime) Sets the last access time (unix timestamp).
void	setLastModificationTime(java.lang.String path, long mtime) Sets the last modification time (unix timestamp).
void	setLength(FileHandle fh, long length) Truncates or lengthens a file.
void	setUnixPermissions(java.lang.String path, UnixPermissions perms) Sets the unix permissions for a file/directory.
void	setWindowsAttributes(java.lang.String path, WindowsAttributes windowsAttributes) Sets the windows attributes.
boolean	supportsUnicodeFilenames() Returns true if the file system supports unicode filenames.
void	unlockFile(FileHandle handle, long byteOffset, long length) Unlocks a file in the specified range.
void	write(FileHandle fh, java.nio.ByteBuffer buffer, long offset) (Over-)writes the buffer into the specified file handle.

Methods inherited from class jfilesyslib.FileSystem

delete, getExtendedAttribute, getMountPath, getNumberOfFilesInDirectory, pathExists

Methods inherited from class java.lang.Object

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

Constructor Detail

CachingFs

public CachingFs(FileSystem innerFs)

Creates a new instance of the caching file system

Parameters:

innerFs - the inner file system

CachingFs

public CachingFs(FileSystem innerFs,
         int cacheSize)

Creates a new instance of the caching file system

Parameters:

innerFs - the inner file system

cacheSize - the cache size per entry in bytes

Method Detail

deleteFile

public void deleteFile(java.lang.String file)
                throws PathNotFoundException,
                       AccessDeniedException

Description copied from class: FileSystem

Deletes a file or symbolic link.

Specified by:

deleteFile in class FileSystem

Parameters:

file - the file

Throws:

PathNotFoundException - the file could not be found

AccessDeniedException - the access is denied

createSymbolicLink

public void createSymbolicLink(java.lang.String from,
                      java.lang.String to)
                        throws PathNotFoundException,
                               SourceAlreadyExistsException,
                               AccessDeniedException,
                               UnsupportedFeatureException

Description copied from class: FileSystem

Creates a symbolic link at source pointing to destination.
The default file system does not support this feature.

Specified by:

createSymbolicLink in class FullFileSystem

Parameters:

from - the source

to - the destination

Throws:

PathNotFoundException - the parent directory (of source) could not be found

SourceAlreadyExistsException - the source does already exist

AccessDeniedException - the access was denied

UnsupportedFeatureException - the feature is unsupported

See Also:

https://en.wikipedia.org/wiki/Symbolic_link

openFile

public FileHandle openFile(java.lang.String path,
                  boolean read,
                  boolean write)
                    throws PathNotFoundException,
                           AccessDeniedException,
                           NotAFileException

Description copied from class: FileSystem

Opens a file.
It is guaranteed that createFile is called first for new files.
You should not overwrite the file if write is true.

Specified by:

openFile in class FileSystem

Parameters:

path - the file to open

read - whether the file should be open to read

write - whether the file should be open to write

Returns:

the file handle

Throws:

PathNotFoundException - the file was not found

AccessDeniedException - the access is denied

NotAFileException - the given path is not a file

createFile

public void createFile(java.lang.String path)
                throws PathNotFoundException,
                       DestinationAlreadyExistsException,
                       AccessDeniedException

Description copied from class: FileSystem

Creates a new (blank) file.

Specified by:

createFile in class FileSystem

Parameters:

path - the path to the file

Throws:

PathNotFoundException - the parent directory could not be found

DestinationAlreadyExistsException - the destination already exists (regardless whether it is a directory or a file)

AccessDeniedException - the access is denied

createDirectory

public void createDirectory(java.lang.String path)
                     throws PathNotFoundException,
                            DestinationAlreadyExistsException,
                            AccessDeniedException

Description copied from class: FileSystem

Creates a new, empty directory.

Specified by:

createDirectory in class FileSystem

Parameters:

path - the path to the new directory

Throws:

PathNotFoundException - the parent directory could not be found

DestinationAlreadyExistsException - the destination already exists (regardless whether it is a directory or a file)

AccessDeniedException - the access is denied

read

public int read(FileHandle fh,
       java.nio.ByteBuffer buffer,
       long offset)

Description copied from class: FileSystem

Reads from a file.
Offset specifies the offset within the opened file, not within the buffer.
The handle is guaranteed to be a valid file handle.

Specified by:

read in class FileSystem

Parameters:

fh - the file handle

buffer - the buffer to fill

offset - the offset within the file

Returns:

the number of read bytes

write

public void write(FileHandle fh,
         java.nio.ByteBuffer buffer,
         long offset)
           throws DriveFullException,
                  PartIsLockedException

Description copied from class: FileSystem

(Over-)writes the buffer into the specified file handle.
Offset specifies the offset within the opened file, not within the buffer.
The handle is guaranteed to be a valid file handle.

Be careful: offset may be larger than the file size!
In this case you should fill everything in between with zeros.

Specified by:

write in class FileSystem

Parameters:

fh - the file handle.

buffer - the buffer to write

offset - the offset within the file

Throws:

DriveFullException - there is no more space

PartIsLockedException - the specified range has been locked

flush

public void flush(FileHandle fh)
           throws DriveFullException

Description copied from class: FileSystem

Should write all pending data in the cache.
It is not guaranteed that this method is called before close.
The handle is guaranteed to be a valid file handle.

Specified by:

flush in class FileSystem

Parameters:

fh - the file handle

Throws:

DriveFullException - there is no more free space

close

public void close(FileHandle fh)
           throws DriveFullException

Description copied from class: FileSystem

Closes the file handle.
The handle is guaranteed to be a valid file handle and not closed yet.

Specified by:

close in class FileSystem

Parameters:

fh - the file handle

Throws:

DriveFullException - there is no more space

deleteDirectoryRecursively

public void deleteDirectoryRecursively(java.lang.String directory)
                                throws PathNotFoundException,
                                       AccessDeniedException

Description copied from class: FileSystem

Deletes a directory recursively.

Specified by:

deleteDirectoryRecursively in class FileSystem

Parameters:

directory - the directory

Throws:

PathNotFoundException - the directory could not be found

AccessDeniedException - the access is denied

listDirectory

public java.lang.Iterable<EntityInfo> listDirectory(java.lang.String path)
                                             throws NotADirectoryException,
                                                    PathNotFoundException,
                                                    AccessDeniedException

Description copied from class: FileSystem

Reads a given directory and returns an iterator.

Specified by:

listDirectory in class FileSystem

Parameters:

path - the path

Returns:

the iterator

Throws:

NotADirectoryException - the path is not a directory

PathNotFoundException - the path could not be found

AccessDeniedException - the access is denied

getFileMetaData

public EntityInfo getFileMetaData(java.lang.String path)
                           throws PathNotFoundException

Description copied from class: FileSystem

Returns some meta data about the path.

Specified by:

getFileMetaData in class FileSystem

Parameters:

path - the path

Returns:

the meta data

Throws:

PathNotFoundException - the path could not be found

rename

public void rename(java.lang.String from,
          java.lang.String to)
            throws PathNotFoundException,
                   DestinationAlreadyExistsException,
                   AccessDeniedException

Description copied from class: FileSystem

Renames a file/directory/symbolic link.
It is equivalent to moving a file/directory.

Specified by:

rename in class FileSystem

Parameters:

from - the source path

to - the destination path

Throws:

PathNotFoundException - the source path or the parent directory of the destination could not be found

DestinationAlreadyExistsException - the destination already exists

AccessDeniedException - the access is denied

getVolumeName

public java.lang.String getVolumeName()

Description copied from class: FileSystem

Returns the volume name.

Specified by:

getVolumeName in class FileSystem

Returns:

the volume name

getFileSystemName

public java.lang.String getFileSystemName()

Description copied from class: FileSystem

Returns the file system name

Specified by:

getFileSystemName in class FileSystem

Returns:

the file system name

setLength

public void setLength(FileHandle fh,
             long length)
               throws DriveFullException

Description copied from class: FileSystem

Truncates or lengthens a file.
The handle is guaranteed to be a valid file handle.

Specified by:

setLength in class FileSystem

Parameters:

fh - the file handle

length - the new file size in bytes

Throws:

DriveFullException - there is no more space

setLastAccessTime

public void setLastAccessTime(java.lang.String path,
                     long atime)
                       throws PathNotFoundException,
                              AccessDeniedException

Description copied from class: FileSystem

Sets the last access time (unix timestamp).

Specified by:

setLastAccessTime in class FileSystem

Parameters:

path - the path

atime - the last access time (unix timestamp)

Throws:

PathNotFoundException - the path could not be found.

AccessDeniedException - the access is denied

setLastModificationTime

public void setLastModificationTime(java.lang.String path,
                           long mtime)
                             throws PathNotFoundException,
                                    AccessDeniedException

Description copied from class: FileSystem

Sets the last modification time (unix timestamp).

Specified by:

setLastModificationTime in class FileSystem

Parameters:

path - the path

mtime - the last modification time (unix timestamp)

Throws:

PathNotFoundException - the path could not be found.

AccessDeniedException - the access is denied

setCreationTime

public void setCreationTime(java.lang.String path,
                   long creationTime)
                     throws PathNotFoundException,
                            AccessDeniedException

Description copied from class: FileSystem

Sets the creation time (unix timestamp).

Specified by:

setCreationTime in class FileSystem

Parameters:

path - the path

creationTime - the creation time (unix timestamp)

Throws:

PathNotFoundException - the path could not be found.

AccessDeniedException - the access is denied

isCaseSensitive

public boolean isCaseSensitive()

Description copied from class: FileSystem

Returns true if the pathes are case sensitive

Specified by:

isCaseSensitive in class FileSystem

Returns:

true if the pathes are case sensitive

getBlockSize

public int getBlockSize()

Description copied from class: FileSystem

Returns the block size in bytes

Specified by:

getBlockSize in class FileSystem

Returns:

the block size

getTotalBlockCount

public long getTotalBlockCount()

Description copied from class: FileSystem

Returns the number of total blocks. E.g. a virtual 40 mb hard drive with 1 mb block size has 40 total blocks.

Specified by:

getTotalBlockCount in class FileSystem

Returns:

the number of total blocks

getFreeBlockCount

public long getFreeBlockCount()

Description copied from class: FileSystem

Returns the number of free blocks.

Specified by:

getFreeBlockCount in class FileSystem

Returns:

the number of free blocks

getFilesFreeCount

public int getFilesFreeCount()

Description copied from class: FileSystem

Returns the number of files which may be created.

Specified by:

getFilesFreeCount in class FullFileSystem

Returns:

the number of files which may be created

getTotalFilesCount

public int getTotalFilesCount()

Description copied from class: FileSystem

Returns the total number of files on the volume.
By default it returns 0, but it does not seem to harmful.

Specified by:

getTotalFilesCount in class FullFileSystem

Returns:

the total number of files

getFreeBlockAvailableCount

public long getFreeBlockAvailableCount()

Description copied from class: FileSystem

Returns the number of free blocks, which are available to the current user.
In the easiast case:
Available Free Block Count = Free Block Count

Specified by:

getFreeBlockAvailableCount in class FileSystem

Returns:

the number of free blocks

supportsUnicodeFilenames

public boolean supportsUnicodeFilenames()

Description copied from class: FileSystem

Returns true if the file system supports unicode filenames.
Since most file systems use Java Strings to encode file names, the default value is true.

Specified by:

supportsUnicodeFilenames in class FullFileSystem

Returns:

true if the file system supports unicode filenames.

isCompressed

public boolean isCompressed()

Description copied from class: FileSystem

Returns true if the file system is compressed

Specified by:

isCompressed in class FullFileSystem

Returns:

true if the file system is compressed

getVolumeSerialNumber

public int getVolumeSerialNumber()

Description copied from class: FileSystem

Returns a volume serial number

Specified by:

getVolumeSerialNumber in class FullFileSystem

Returns:

a volume serial number

isReadOnly

public boolean isReadOnly()

Description copied from class: FileSystem

Returns true if the file system is read only

Specified by:

isReadOnly in class FullFileSystem

Returns:

true if the file system is read only

createHardLink

public void createHardLink(java.lang.String source,
                  java.lang.String destination)
                    throws PathNotFoundException,
                           SourceAlreadyExistsException,
                           AccessDeniedException,
                           UnsupportedFeatureException

Description copied from class: FileSystem

Creates a hard link at source pointing to destination.
The default file system does not support this feature.

Specified by:

createHardLink in class FullFileSystem

Parameters:

source - the source

destination - the destination

Throws:

PathNotFoundException - the parent directory could not be found

SourceAlreadyExistsException - the source does already exist

AccessDeniedException - the access was denied

UnsupportedFeatureException - the feature is unsupported

See Also:

https://en.wikipedia.org/wiki/Hard_link

getMaxPathLength

public int getMaxPathLength()

Description copied from class: FileSystem

Returns the maximum path length. The default value is 32768.

Specified by:

getMaxPathLength in class FullFileSystem

Returns:

the maximum path length

setUnixPermissions

public void setUnixPermissions(java.lang.String path,
                      UnixPermissions perms)
                        throws PathNotFoundException,
                               AccessDeniedException,
                               UnsupportedFeatureException

Description copied from class: FileSystem

Sets the unix permissions for a file/directory.
This feature is not supported by default.

Specified by:

setUnixPermissions in class FullFileSystem

Parameters:

path - the path

perms - the permissions

Throws:

PathNotFoundException - the path was not found

AccessDeniedException - the access is denied

UnsupportedFeatureException - the feature is unsupported

getUnixPermissions

public UnixPermissions getUnixPermissions(java.lang.String path)
                                   throws PathNotFoundException

Description copied from class: FileSystem

Returns the unix permissions

Specified by:

getUnixPermissions in class FullFileSystem

Parameters:

path - the path

Returns:

the permissions

Throws:

PathNotFoundException - the path was not found

setWindowsAttributes

public void setWindowsAttributes(java.lang.String path,
                        WindowsAttributes windowsAttributes)
                          throws PathNotFoundException,
                                 AccessDeniedException,
                                 UnsupportedFeatureException

Description copied from class: FileSystem

Sets the windows attributes.
This feature is not supported by default.

Specified by:

setWindowsAttributes in class FullFileSystem

Parameters:

path - the path

windowsAttributes - the windows attributes

Throws:

PathNotFoundException - the path was not found

AccessDeniedException - the access is denied

UnsupportedFeatureException - the feature is not supported

getWindowsAttributes

public WindowsAttributes getWindowsAttributes(java.lang.String path)
                                       throws PathNotFoundException,
                                              AccessDeniedException,
                                              UnsupportedFeatureException

Description copied from class: FileSystem

Returns the windows attributes.
The default implementation:
If the file system is read only, it returns the read only attribute.
If not, it does not return any attribute.

Specified by:

getWindowsAttributes in class FullFileSystem

Parameters:

path - the path

Returns:

the windows attributes

Throws:

PathNotFoundException - the path was not found

AccessDeniedException - the access is denied

UnsupportedFeatureException - the feature is not supported

lockFile

public void lockFile(FileHandle handle,
            long byteOffset,
            long length)
              throws PathNotFoundException,
                     AccessDeniedException,
                     NotAFileException,
                     UnsupportedFeatureException,
                     AlreadyLockedException

Description copied from class: FileSystem

Locks a file in the specified range for every write access except for the File Handle handle.
This is windows specific.
This feature is not supported by default.

Specified by:

lockFile in class FullFileSystem

Parameters:

handle - the file handle

byteOffset - the byte offset

length - the length

Throws:

PathNotFoundException - the path was not found

AccessDeniedException - the access is denied

NotAFileException - the path is not a file

UnsupportedFeatureException - the feature is not supported

AlreadyLockedException - parts of the specified range are already locked

unlockFile

public void unlockFile(FileHandle handle,
              long byteOffset,
              long length)
                throws PathNotFoundException,
                       AccessDeniedException,
                       NotAFileException,
                       UnsupportedFeatureException

Description copied from class: FileSystem

Unlocks a file in the specified range.
This is windows specific.
The caller does not perform a check that the file handle is identical to the locker's file handle.
This feature is not supported by default.

Specified by:

unlockFile in class FullFileSystem

Parameters:

handle - the file handle

byteOffset - the byte offset

length - the length

Throws:

PathNotFoundException - the path was not found

AccessDeniedException - the access is denied

NotAFileException - the path is not a file

UnsupportedFeatureException - the feature is not supported

listExtendedAttributes

public java.lang.Iterable<ExtendedAttribute> listExtendedAttributes(java.lang.String path)
                                                             throws PathNotFoundException,
                                                                    AccessDeniedException,
                                                                    UnsupportedFeatureException

Description copied from class: FileSystem

Lists the extended attributes of a path.
This feature is not supported by default.

Specified by:

listExtendedAttributes in class FullFileSystem

Parameters:

path - the path

Returns:

the extended attributes

Throws:

PathNotFoundException - the path was not found

AccessDeniedException - the access is denied

UnsupportedFeatureException - the feature is not supported

setExtendedAttribute

public void setExtendedAttribute(java.lang.String path,
                        ExtendedAttribute attribute)
                          throws PathNotFoundException,
                                 AccessDeniedException,
                                 UnsupportedFeatureException

Description copied from class: FileSystem

Sets or adds extended attribute.
This feature is not supported by default.

Specified by:

setExtendedAttribute in class FullFileSystem

Parameters:

path - the path

attribute - the attribute to add/set

Throws:

PathNotFoundException - the path was not found

AccessDeniedException - the access is denied

UnsupportedFeatureException - the feature is not supported

removeExtendedAttribute

public void removeExtendedAttribute(java.lang.String path,
                           java.lang.String attributeName)
                             throws PathNotFoundException,
                                    AccessDeniedException,
                                    UnsupportedFeatureException,
                                    AttributeNotFoundException

Description copied from class: FileSystem

Sets or adds extended attributes.
This feature is not supported by default.

Specified by:

removeExtendedAttribute in class FullFileSystem

Parameters:

path - the path

attributeName - the attribute name

Throws:

PathNotFoundException - the path was not found

AccessDeniedException - the access is denied

UnsupportedFeatureException - the feature is not supported

AttributeNotFoundException - the specified attribute was not found

beforeMounting

public void beforeMounting(java.lang.String mountPath)

Description copied from class: FileSystem

Is called directly before the file system is mounted

Specified by:

beforeMounting in class FullFileSystem

Parameters:

mountPath - the mount path

beforeUnmounting

public void beforeUnmounting()

Description copied from class: FileSystem

Is called directly before the file system is unmounted

Specified by:

beforeUnmounting in class FullFileSystem

afterUnmounting

public void afterUnmounting()

Description copied from class: FileSystem

Is called after the file system has been unmounted successfully.

Specified by:

afterUnmounting in class FullFileSystem