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

Class FileIOEngine

java.lang.Object

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

All Implemented Interfaces:

IOEngine

@InterfaceAudience.Private
public class FileIOEngine
extends Object
implements IOEngine

IO engine that stores data to a file on the local file system.

Field Summary

Fields

Modifier and Type	Field and Description
static String	FILE_DELIMITER

Constructor Summary

Constructors

Constructor and Description
FileIOEngine(long capacity, boolean maintainPersistence, String... filePaths)

Method Summary

Modifier and Type	Method and Description
boolean	isPersistent() File IO engine is always able to support persistent storage for the cache
Cacheable	read(long offset, int length, CacheableDeserializer<Cacheable> deserializer) Transfers data from file to the given byte buffer
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

FILE_DELIMITER

public static final String FILE_DELIMITER

See Also:

Constant Field Values

Constructor Detail

FileIOEngine

public FileIOEngine(long capacity,
                    boolean maintainPersistence,
                    String... filePaths)
             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 Cacheable read(long offset,
                      int length,
                      CacheableDeserializer<Cacheable> deserializer)
               throws IOException

Transfers data from file to the given byte buffer

Specified by:

read in interface IOEngine

Parameters:

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

length - The length of buffer that should be allocated for reading from the file channel

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

Returns:

number of bytes read

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

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

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