org.mapdb
Class Volume

java.lang.Object
  org.mapdb.Volume

Direct Known Subclasses:

Volume.ByteBufferVol, Volume.FileChannelVol

public abstract class Volume
extends Object

MapDB abstraction over raw storage (file, disk partition, memory etc...).

Implementations needs to be thread safe (especially 'ensureAvailable') operation. However updates do not have to be atomic, it is clients responsibility to ensure two threads are not writing/reading into the same location.

Author:

Jan Kotek

Nested Class Summary

static class	Volume.ByteBufferVol Abstract Volume over bunch of ByteBuffers It leaves ByteBufferVol details (allocation, disposal) on subclasses.
static interface	Volume.Factory Factory which creates two/three volumes used by each MapDB Storage Engine
static class	Volume.FileChannelVol Volume which uses FileChannel.
static class	Volume.MappedFileVol
static class	Volume.MemoryVol

Constructor Summary

Volume()

Method Summary

abstract void	close()
abstract void	deleteFile()
void	ensureAvailable(long offset) Check space allocated by Volume is bigger or equal to given offset.
static Volume.Factory	fileFactory(File indexFile, int rafMode, boolean readOnly, long sizeLimit, int chunkShift, int sizeIncrement)
static Volume.Factory	fileFactory(File indexFile, int rafMode, boolean readOnly, long sizeLimit, int chunkShift, int sizeIncrement, File physFile, File transLogFile)
abstract byte	getByte(long offset)
abstract DataInput	getDataInput(long offset, int size)
abstract File	getFile() returns underlying file if it exists
abstract int	getInt(long offset)
abstract long	getLong(long offset)
long	getPackedLong(long pos)
long	getSixLong(long pos) Reads a long from the indicated position
int	getUnsignedByte(long offset)
int	getUnsignedShort(long offset)
abstract boolean	isEmpty()
abstract boolean	isSliced()
static Volume.Factory	memoryFactory(boolean useDirectBuffer, long sizeLimit, int chunkShift)
abstract void	putByte(long offset, byte value)
abstract void	putData(long offset, byte[] src, int srcPos, int srcSize)
abstract void	putData(long offset, ByteBuffer buf)
abstract void	putInt(long offset, int value)
abstract void	putLong(long offset, long value)
int	putPackedLong(long pos, long value) Writes packed long at given position and returns number of bytes used.
void	putSixLong(long pos, long value) Writes a long to the indicated position
void	putUnsignedByte(long offset, int b)
void	putUnsignedShort(long offset, int value)
abstract void	sync()
abstract void	truncate(long size)
abstract boolean	tryAvailable(long offset)
static Volume	volumeForFile(File f, boolean useRandomAccessFile, boolean readOnly, long sizeLimit, int chunkShift, int sizeIncrement)
static void	volumeTransfer(long size, Volume from, Volume to) transfer data from one volume to second.

Methods inherited from class java.lang.Object

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

Constructor Detail

Volume

public Volume()

Method Detail

ensureAvailable

public void ensureAvailable(long offset)

Check space allocated by Volume is bigger or equal to given offset. So it is safe to write into smaller offsets.

Parameters:

offset -

Throws:

IOError - if Volume can not be expanded beyond given offset

tryAvailable

public abstract boolean tryAvailable(long offset)

truncate

public abstract void truncate(long size)

putLong

public abstract void putLong(long offset,
                             long value)

putInt

public abstract void putInt(long offset,
                            int value)

putByte

public abstract void putByte(long offset,
                             byte value)

putData

public abstract void putData(long offset,
                             byte[] src,
                             int srcPos,
                             int srcSize)

putData

public abstract void putData(long offset,
                             ByteBuffer buf)

getLong

public abstract long getLong(long offset)

getInt

public abstract int getInt(long offset)

getByte

public abstract byte getByte(long offset)

getDataInput

public abstract DataInput getDataInput(long offset,
                                       int size)

close

public abstract void close()

sync

public abstract void sync()

isEmpty

public abstract boolean isEmpty()

deleteFile

public abstract void deleteFile()

isSliced

public abstract boolean isSliced()

putUnsignedShort

public void putUnsignedShort(long offset,
                             int value)

getUnsignedShort

public int getUnsignedShort(long offset)

getUnsignedByte

public int getUnsignedByte(long offset)

putUnsignedByte

public void putUnsignedByte(long offset,
                            int b)

getSixLong

public long getSixLong(long pos)

Reads a long from the indicated position

putSixLong

public void putSixLong(long pos,
                       long value)

Writes a long to the indicated position

putPackedLong

public int putPackedLong(long pos,
                         long value)

Writes packed long at given position and returns number of bytes used.

getFile

public abstract File getFile()

returns underlying file if it exists

getPackedLong

public long getPackedLong(long pos)

volumeForFile

public static Volume volumeForFile(File f,
                                   boolean useRandomAccessFile,
                                   boolean readOnly,
                                   long sizeLimit,
                                   int chunkShift,
                                   int sizeIncrement)

fileFactory

public static Volume.Factory fileFactory(File indexFile,
                                         int rafMode,
                                         boolean readOnly,
                                         long sizeLimit,
                                         int chunkShift,
                                         int sizeIncrement)

fileFactory

public static Volume.Factory fileFactory(File indexFile,
                                         int rafMode,
                                         boolean readOnly,
                                         long sizeLimit,
                                         int chunkShift,
                                         int sizeIncrement,
                                         File physFile,
                                         File transLogFile)

memoryFactory

public static Volume.Factory memoryFactory(boolean useDirectBuffer,
                                           long sizeLimit,
                                           int chunkShift)

volumeTransfer

public static void volumeTransfer(long size,
                                  Volume from,
                                  Volume to)

transfer data from one volume to second. Second volume will be expanded if needed