Package org.apache.hadoop.fs.impl.prefetch

Interface BlockCache

All Superinterfaces:

java.lang.AutoCloseable, java.io.Closeable

All Known Implementing Classes:

SingleFilePerBlockCache

public interface BlockCache
extends java.io.Closeable

Provides functionality necessary for caching blocks of data read from FileSystem.

Method Summary

Modifier and Type	Method	Description
java.lang.Iterable<java.lang.Integer>	blocks()	Gets the blocks in this cache.
boolean	containsBlock(int blockNumber)	Indicates whether the given block is in this cache.
void	get(int blockNumber, java.nio.ByteBuffer buffer)	Gets the block having the given blockNumber.
void	put(int blockNumber, java.nio.ByteBuffer buffer, Configuration conf, LocalDirAllocator localDirAllocator)	Puts the given block in this cache.
int	size()	Gets the number of blocks in this cache.

Methods inherited from interface java.io.Closeable

close

Method Detail

containsBlock

boolean containsBlock(int blockNumber)

Indicates whether the given block is in this cache.

Parameters:

blockNumber - the id of the given block.

Returns:

true if the given block is in this cache, false otherwise.

blocks

java.lang.Iterable<java.lang.Integer> blocks()

Gets the blocks in this cache.

Returns:

the blocks in this cache.

size

int size()

Gets the number of blocks in this cache.

Returns:

the number of blocks in this cache.

get

void get(int blockNumber,
         java.nio.ByteBuffer buffer)
  throws java.io.IOException

Gets the block having the given blockNumber.

Parameters:

blockNumber - the id of the desired block.

buffer - contents of the desired block are copied to this buffer.

Throws:

java.io.IOException - if there is an error reading the given block.

put

void put(int blockNumber,
         java.nio.ByteBuffer buffer,
         Configuration conf,
         LocalDirAllocator localDirAllocator)
  throws java.io.IOException

Puts the given block in this cache.

Parameters:

blockNumber - the id of the given block.

buffer - contents of the given block to be added to this cache.

conf - the configuration.

localDirAllocator - the local dir allocator instance.

Throws:

java.io.IOException - if there is an error writing the given block.