de.waldheinz.fs.util
Class FileDisk

java.lang.Object
  de.waldheinz.fs.util.FileDisk

All Implemented Interfaces:

BlockDevice

public final class FileDisk
extends Object
implements BlockDevice

This is a BlockDevice that uses a File as it's backing store.

Author:

Matthias Treydte <matthias.treydte at meetwise.com>

Field Summary

static int

BYTES_PER_SECTOR The number of bytes per sector for all FileDisk instances.

Constructor Summary

FileDisk(File file, boolean readOnly)
Creates a new instance of FileDisk for the specified File.

Method Summary

void	close() Closes this BlockDevice.
static FileDisk	create(File file, long size) Creates a new FileDisk of the specified size.
void	flush() Flushes data in caches to the actual storage.
int	getSectorSize() Returns the size of a sector on this device.
long	getSize() Gets the total length of this device in bytes.
boolean	isClosed() Checks if this device was already closed.
boolean	isReadOnly() Checks if this BlockDevice is read-only.
void	read(long devOffset, ByteBuffer dest) Read a block of data from this device.
void	write(long devOffset, ByteBuffer src) Writes a block of data to this device.

Methods inherited from class java.lang.Object

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

Field Detail

BYTES_PER_SECTOR

public static final int BYTES_PER_SECTOR

The number of bytes per sector for all FileDisk instances.

See Also:

Constant Field Values

Constructor Detail

FileDisk

public FileDisk(File file,
                boolean readOnly)
         throws FileNotFoundException

Creates a new instance of FileDisk for the specified File.

Parameters:

file - the file that holds the disk contents

readOnly - if the file should be opened in read-only mode, which will result in a read-only FileDisk instance

Throws:

FileNotFoundException - if the specified file does not exist

See Also:

isReadOnly()

Method Detail

create

public static FileDisk create(File file,
                              long size)
                       throws IOException

Creates a new FileDisk of the specified size. The FileDisk returned by this method will be writable.

Parameters:

file - the file to hold the FileDisk contents

size - the size of the new FileDisk

Returns:

the created FileDisk instance

Throws:

IOException - on error creating the FileDisk

getSize

public long getSize()
             throws IOException

Description copied from interface: BlockDevice

Gets the total length of this device in bytes.

Specified by:

getSize in interface BlockDevice

Returns:

the total number of bytes on this device

Throws:

IOException - on error getting the size of this device

read

public void read(long devOffset,
                 ByteBuffer dest)
          throws IOException

Description copied from interface: BlockDevice

Read a block of data from this device.

Specified by:

read in interface BlockDevice

Parameters:

devOffset - the byte offset where to read the data from

dest - the destination buffer where to store the data read

Throws:

IOException - on read error

write

public void write(long devOffset,
                  ByteBuffer src)
           throws IOException

Description copied from interface: BlockDevice

Writes a block of data to this device.

Specified by:

write in interface BlockDevice

Parameters:

devOffset - the byte offset where to store the data

src - the source ByteBuffer to write to the device

Throws:

IOException - on write error

See Also:

BlockDevice.isReadOnly()

flush

public void flush()
           throws IOException

Description copied from interface: BlockDevice

Flushes data in caches to the actual storage.

Specified by:

flush in interface BlockDevice

Throws:

IOException - on write error

getSectorSize

public int getSectorSize()

Description copied from interface: BlockDevice

Returns the size of a sector on this device.

Specified by:

getSectorSize in interface BlockDevice

Returns:

the sector size in bytes

close

public void close()
           throws IOException

Description copied from interface: BlockDevice

Closes this BlockDevice. No methods of this device may be accesses after this method was called.

Specified by:

close in interface BlockDevice

Throws:

IOException - on error closing this device

See Also:

BlockDevice.isClosed()

isClosed

public boolean isClosed()

Description copied from interface: BlockDevice

Checks if this device was already closed. No methods may be called on a closed device (except this method).

Specified by:

isClosed in interface BlockDevice

Returns:

if this device is closed

isReadOnly

public boolean isReadOnly()

Description copied from interface: BlockDevice

Checks if this BlockDevice is read-only.

Specified by:

isReadOnly in interface BlockDevice

Returns:

if this BlockDevice is read-only