org.planx.xmlstore.io
Class LocalFileSystem

java.lang.Object
  org.planx.xmlstore.io.LocalFileSystem

All Implemented Interfaces:

FileSystem

public class LocalFileSystem
extends Object
implements FileSystem

An implementation of FileSystem that uses an on-disk file. It is not synchronized and should thus be synchronized externally.

Author:

Thomas Ambus

Constructor Summary

LocalFileSystem(String name)
Creates a new file system with the specified file name or recreates a previously persisted one.

Method Summary

LocalLocator	all() Returns a LocalLocator to all content currently in this FileSystem.
LocalLocator	allocate() Returns a LocalLocator to a free write position that can hold size number of bytes.
LocalLocator	allocate(int size)
LocalLocator	allocate(int size, FileSystemIdentifier id)
void	close() Closes the file system and releases all resources.
void	copy(FileSystem fs, LocalLocator fromLoc, LocalLocator locTo) Copies the data at fromLoc in the specified FileSystem to toLoc in this FileSystem.
FileSystemIdentifier	currentIdentifier()
void	free(LocalLocator l) Frees the space occupied by the specified LocalLocator.
DataInput	getInput(LocalLocator l) Positions the input at the specified location and returns a DataInput for reading.
DataOutput	getOutput(LocalLocator l) Positions the output at the specified location and returns a DataOutpu for writing.
boolean	isContained(LocalLocator loc) Returns true if the specified LocalLocator originates from this FileSystem.
long	size() Returns the size of the FileSystem.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

LocalFileSystem

public LocalFileSystem(String name)
                throws IOException

Creates a new file system with the specified file name or recreates a previously persisted one.

Throws:

IOException

Method Detail

currentIdentifier

public FileSystemIdentifier currentIdentifier()

Specified by:

currentIdentifier in interface FileSystem

size

public long size()
          throws IOException

Description copied from interface: FileSystem

Returns the size of the FileSystem.

Specified by:

size in interface FileSystem

Throws:

IOException

close

public void close()
           throws IOException

Description copied from interface: FileSystem

Closes the file system and releases all resources.

Specified by:

close in interface FileSystem

Throws:

IOException

copy

public void copy(FileSystem fs,
                 LocalLocator fromLoc,
                 LocalLocator locTo)
          throws IOException,
                 UnknownLocatorException

Description copied from interface: FileSystem

Copies the data at fromLoc in the specified FileSystem to toLoc in this FileSystem.

Specified by:

copy in interface FileSystem

Throws:

IOException

UnknownLocatorException

getInput

public DataInput getInput(LocalLocator l)
                   throws IOException,
                          UnknownLocatorException

Description copied from interface: FileSystem

Positions the input at the specified location and returns a DataInput for reading. The DataInput is shared so if multiple threads operate on the same FileSystem concurrently, external synchronization should be used.

Specified by:

getInput in interface FileSystem

Throws:

IOException

UnknownLocatorException

getOutput

public DataOutput getOutput(LocalLocator l)
                     throws IOException,
                            UnknownLocatorException

Description copied from interface: FileSystem

Positions the output at the specified location and returns a DataOutpu for writing. Note, that this can overwrite existing data. The DataInput is shared so if multiple threads operate on the same FileSystem concurrently, external synchronization should be used. When writing new data FileSystem.allocate() should be called first.

Specified by:

getOutput in interface FileSystem

Throws:

IOException

UnknownLocatorException

all

public LocalLocator all()
                 throws IOException

Description copied from interface: FileSystem

Returns a LocalLocator to all content currently in this FileSystem.

Specified by:

all in interface FileSystem

Throws:

IOException

allocate

public LocalLocator allocate()
                      throws IOException

Description copied from interface: FileSystem

Returns a LocalLocator to a free write position that can hold size number of bytes.

Specified by:

allocate in interface FileSystem

Throws:

IOException

allocate

public LocalLocator allocate(int size)
                      throws IOException

Specified by:

allocate in interface FileSystem

Throws:

IOException

allocate

public LocalLocator allocate(int size,
                             FileSystemIdentifier id)
                      throws IOException

Specified by:

allocate in interface FileSystem

Throws:

IOException

free

public void free(LocalLocator l)
          throws IOException,
                 UnknownLocatorException

Description copied from interface: FileSystem

Frees the space occupied by the specified LocalLocator.

Specified by:

free in interface FileSystem

Throws:

IOException

UnknownLocatorException

isContained

public boolean isContained(LocalLocator loc)

Description copied from interface: FileSystem

Returns true if the specified LocalLocator originates from this FileSystem.

Specified by:

isContained in interface FileSystem

toString

public String toString()

Overrides:

toString in class Object