org.apache.cassandra.io.util

Interface ChunkReader

All Superinterfaces:

java.lang.AutoCloseable, ReaderFileProxy, RebuffererFactory

All Known Implementing Classes:

CompressedChunkReader, CompressedChunkReader.Mmap, CompressedChunkReader.Standard

public interface ChunkReader
extends RebuffererFactory

RandomFileReader component that reads data from a file into a provided buffer and may have requirements over the size and alignment of reads. A caching or buffer-managing rebufferer will reference one of these to do the actual reading. Note: Implementations of this interface must be thread-safe!

Method Summary

Modifier and Type	Method and Description
int	chunkSize() Buffer size required for this rebufferer.
BufferType	preferredBufferType() Specifies type of buffer the caller should attempt to give.
void	readChunk(long position, java.nio.ByteBuffer buffer) Read the chunk at the given position, attempting to fill the capacity of the given buffer.

Methods inherited from interface org.apache.cassandra.io.util.RebuffererFactory

instantiateRebufferer

Methods inherited from interface org.apache.cassandra.io.util.ReaderFileProxy

channel, close, fileLength, getCrcCheckChance

Method Detail

readChunk

void readChunk(long position,
               java.nio.ByteBuffer buffer)

Read the chunk at the given position, attempting to fill the capacity of the given buffer. The filled buffer must be positioned at 0, with limit set at the size of the available data. The source may have requirements for the positioning and/or size of the buffer (e.g. chunk-aligned and chunk-sized). These must be satisfied by the caller.

chunkSize

int chunkSize()

Buffer size required for this rebufferer. Must be power of 2 if alignment is required.

preferredBufferType

BufferType preferredBufferType()

Specifies type of buffer the caller should attempt to give. This is not guaranteed to be fulfilled.