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

Class FileMmapIOEngine

java.lang.Object

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

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

All Implemented Interfaces:

IOEngine

Direct Known Subclasses:

ExclusiveMemoryMmapIOEngine, SharedMemoryMmapIOEngine

@Private
public abstract class FileMmapIOEngine
extends PersistentIOEngine

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

Field Summary

Fields

Modifier and Type	Field	Description
protected ByteBufferArray	bufferArray
private final FileChannel	fileChannel
(package private) static final org.slf4j.Logger	LOG
protected final String	path
private RandomAccessFile	raf
protected long	size

Fields inherited from class org.apache.hadoop.hbase.io.hfile.bucket.PersistentIOEngine

filePaths

Constructor Summary

Constructors

Constructor	Description
FileMmapIOEngine(String filePath, long capacity)

Method Summary

Modifier and Type	Method	Description
boolean	isPersistent()	File IO engine is always able to support persistent storage for the cache
abstract Cacheable	read(BucketEntry be)	Transfers data from IOEngine to a Cacheable object.
private long	roundUp(long n, long to)
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 org.apache.hadoop.hbase.io.hfile.bucket.PersistentIOEngine

calculateChecksum, verifyFileIntegrity

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 Details

LOG

static final org.slf4j.Logger LOG

path

protected final String path

size

protected long size

bufferArray

protected ByteBufferArray bufferArray

fileChannel

private final FileChannel fileChannel

raf

private RandomAccessFile raf

Constructor Details

FileMmapIOEngine

public FileMmapIOEngine(String filePath,
 long capacity)
                 throws IOException

Throws:

IOException

Method Details

roundUp

private long roundUp(long n,
 long to)

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

read

public abstract Cacheable read(BucketEntry be)
                        throws IOException

Description copied from interface: IOEngine

Transfers data from IOEngine to a Cacheable object.

Parameters:

be - maintains an (offset,len,refCnt) inside.

Returns:

Cacheable which will wrap the NIO ByteBuffers from IOEngine.

Throws:

IOException - when any IO error happen

write

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

Transfers data from the given byte buffer to file

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

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

Throws:

IOException

shutdown

public void shutdown()

Close the file