org.apache.flink.runtime.state.heap.space

Interface Chunk

public interface Chunk

Chunk is a logically contiguous space backed by one or multiple ByteBuffer.

For example: a Chunk of 1G size may be backed by one MappedByteBuffer from a memory-mapped 1G file, or multiple HeapByteBuffer/DirectByteBuffer.

Method Summary

Modifier and Type	Method and Description
int	allocate(int len) Try to allocate size bytes from the chunk.
void	free(int interChunkOffset) release the space addressed by interChunkOffset.
int	getChunkCapacity()
int	getChunkId()
MemorySegment	getMemorySegment(int chunkOffset)
int	getOffsetInSegment(int offsetInChunk)

Method Detail

allocate

int allocate(int len)

Try to allocate size bytes from the chunk.

Parameters:

len - size of bytes to allocate.

Returns:

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

free

void free(int interChunkOffset)

release the space addressed by interChunkOffset.

Parameters:

interChunkOffset - offset of the chunk

getChunkId

int getChunkId()

Returns:

Id of this Chunk

getChunkCapacity

int getChunkCapacity()

getMemorySegment

MemorySegment getMemorySegment(int chunkOffset)

Returns:

This chunk's backing MemorySegment described by chunkOffset.

getOffsetInSegment

int getOffsetInSegment(int offsetInChunk)

Parameters:

offsetInChunk - virtual and global address in chunk

Returns:

chunk maybe compose of multi MemorySegments, return the offset in certain one.