org.apache.hadoop.hbase.io.hfile.bucket

Class FileMmapIOEngine

java.lang.Object

org.apache.hadoop.hbase.io.hfile.bucket.FileMmapIOEngine

All Implemented Interfaces:

IOEngine

Direct Known Subclasses:

ExclusiveMemoryMmapIOEngine, SharedMemoryMmapIOEngine

@InterfaceAudience.Private
public abstract class FileMmapIOEngine
extends Object
implements IOEngine

IO engine that stores data to a file on the specified file system using memory mapping mechanism

Field Summary

Fields

Modifier and Type	Field and Description
protected ByteBufferArray	bufferArray
protected String	path
protected long	size

Constructor Summary

Constructors

Constructor and Description
FileMmapIOEngine(String filePath, long capacity)

Method Summary

Modifier and Type	Method and Description
boolean	isPersistent() File IO engine is always able to support persistent storage for the cache
abstract Cacheable	read(long offset, int length, CacheableDeserializer<Cacheable> deserializer) Transfers data from IOEngine to a Cacheable object.
void	shutdown() Close the file
void	sync() Sync the data to file after writing
String	toString()
void	write(ByteBuffer srcBuffer, long offset) Transfers data from the given byte buffer to file
void	write(ByteBuff srcBuffer, long offset) Transfers the data from the given MultiByteBuffer to IOEngine

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.hadoop.hbase.io.hfile.bucket.IOEngine

usesSharedMemory

Field Detail

path

protected final String path

size

protected long size

bufferArray

protected ByteBufferArray bufferArray

Constructor Detail

FileMmapIOEngine

public FileMmapIOEngine(String filePath,
                        long capacity)
                 throws IOException

Throws:

IOException

Method Detail

toString

public String toString()

Overrides:

toString in class Object

isPersistent

public boolean isPersistent()

File IO engine is always able to support persistent storage for the cache

Specified by:

isPersistent in interface IOEngine

Returns:

true

read

public abstract Cacheable read(long offset,
                               int length,
                               CacheableDeserializer<Cacheable> deserializer)
                        throws IOException

Description copied from interface: IOEngine

Transfers data from IOEngine to a Cacheable object.

Specified by:

read in interface IOEngine

Parameters:

offset - The offset in the IO engine where the first byte to be read

length - How many bytes to be read from the offset

deserializer - The deserializer to be used to make a Cacheable from the data.

Returns:

Cacheable

Throws:

IOException

write

public void write(ByteBuffer srcBuffer,
                  long offset)
           throws IOException

Transfers data from the given byte buffer to file

Specified by:

write in interface IOEngine

Parameters:

srcBuffer - the given byte buffer from which bytes are to be read

offset - The offset in the file where the first byte to be written

Throws:

IOException

write

public void write(ByteBuff srcBuffer,
                  long offset)
           throws IOException

Description copied from interface: IOEngine

Transfers the data from the given MultiByteBuffer to IOEngine

Specified by:

write in interface IOEngine

Parameters:

srcBuffer - the given MultiBytebufffers from which bytes are to be read

offset - the offset in the IO engine where the first byte to be written

Throws:

IOException

sync

public void sync()
          throws IOException

Sync the data to file after writing

Specified by:

sync in interface IOEngine

Throws:

IOException

shutdown

public void shutdown()

Close the file

Specified by:

shutdown in interface IOEngine