Package org.apache.hadoop.hbase.regionserver

Class Chunk

java.lang.Object

org.apache.hadoop.hbase.regionserver.Chunk

Direct Known Subclasses:

OffheapChunk, OnheapChunk

@Private
public abstract class Chunk
extends Object

A chunk of memory out of which allocations are sliced.

Field Summary

Fields

Modifier and Type	Field	Description
protected AtomicInteger	allocCount	Total number of allocations satisfied from this buffer
private final ChunkCreator.ChunkType	chunkType
protected ByteBuffer	data	Actual underlying data
private final boolean	fromPool
private final int	id
protected AtomicInteger	nextFreeOffset	Offset for the next allocation, or the sentinel value -1 which implies that the chunk is still uninitialized.
protected static final int	OOM
protected final int	size	Size of chunk in bytes
protected static final int	UNINITIALIZED

Constructor Summary

Constructors

Constructor	Description
Chunk(int size, int id, ChunkCreator.ChunkType chunkType)	Create an uninitialized chunk.
Chunk(int size, int id, ChunkCreator.ChunkType chunkType, boolean fromPool)	Create an uninitialized chunk.

Method Summary

Modifier and Type	Method	Description
int	alloc(int size)	Try to allocate size bytes from the chunk.
(package private) abstract void	allocateDataBuffer()
(package private) ChunkCreator.ChunkType	getChunkType()
(package private) ByteBuffer	getData()	Returns This chunk's backing data.
(package private) int	getId()
(package private) int	getNextFreeOffset()
void	init()	Actually claim the memory for this chunk.
(package private) boolean	isDataChunk()
(package private) boolean	isFromPool()
(package private) boolean	isIndexChunk()
(package private) boolean	isJumbo()
(package private) void	reset()	Reset the offset to UNINITIALIZED before before reusing an old chunk
String	toString()

Methods inherited from class java.lang.Object

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

Field Details

data

protected ByteBuffer data

Actual underlying data

UNINITIALIZED

protected static final int UNINITIALIZED

See Also:

• Constant Field Values

OOM

protected static final int OOM

See Also:

• Constant Field Values

nextFreeOffset

protected AtomicInteger nextFreeOffset

Offset for the next allocation, or the sentinel value -1 which implies that the chunk is still uninitialized.

allocCount

protected AtomicInteger allocCount

Total number of allocations satisfied from this buffer

size

protected final int size

Size of chunk in bytes

id

private final int id

chunkType

private final ChunkCreator.ChunkType chunkType

fromPool

private final boolean fromPool

Constructor Details

Chunk

public Chunk(int size,
 int id,
 ChunkCreator.ChunkType chunkType)

Create an uninitialized chunk. Note that memory is not allocated yet, so this is cheap.

Parameters:

size - in bytes

id - the chunk id

Chunk

public Chunk(int size,
 int id,
 ChunkCreator.ChunkType chunkType,
 boolean fromPool)

Create an uninitialized chunk. Note that memory is not allocated yet, so this is cheap.

Parameters:

size - in bytes

id - the chunk id

fromPool - if the chunk is formed by pool

Method Details

getId

int getId()

getChunkType

ChunkCreator.ChunkType getChunkType()

isFromPool

boolean isFromPool()

isJumbo

boolean isJumbo()

isIndexChunk

boolean isIndexChunk()

isDataChunk

boolean isDataChunk()

init

public void init()

Actually claim the memory for this chunk. This should only be called from the thread that constructed the chunk. It is thread-safe against other threads calling alloc(), who will block until the allocation is complete.

allocateDataBuffer

abstract void allocateDataBuffer()

reset

void reset()

Reset the offset to UNINITIALIZED before before reusing an old chunk

alloc

public int alloc(int size)

Try to allocate size bytes from the chunk. If a chunk is tried to get allocated before init() call, the thread doing the allocation will be in busy-wait state as it will keep looping till the nextFreeOffset is set.

Returns:

the offset of the successful allocation, or -1 to indicate not-enough-space

getData

ByteBuffer getData()

Returns This chunk's backing data.

toString

public String toString()

Overrides:

toString in class Object

getNextFreeOffset

int getNextFreeOffset()