iitb.con.io
Class MemMapFileAdapter

java.lang.Object
  iitb.con.io.MemMapFileAdapter

All Implemented Interfaces:

IOAdapter

public class MemMapFileAdapter
extends java.lang.Object
implements IOAdapter

MemMapFileAdapter uses MappedByteBuffer as the buffer which maps the file contents to memory for the read and write file operations. It uses RandomAccessFile as the file operation mode.

Constructor Summary

MemMapFileAdapter(java.lang.String name, java.lang.String mode)
Initializes the MemMapFileAdapter with file name and mode.

Method Summary

void	close() Closes the IO Adapter
long	getFileLength() Returns the length of the file
byte[]	read(long location, int length) Reads the contents and return it as byte array.
java.nio.ByteBuffer[]	readFileAsBlocks() Reads the entire contents of the file as ByteBuffer array. The contents as divided as block based on the block size value
java.nio.ByteBuffer	readIntoBuffer(long location) Reads the contents into the temporary buffer and returns it as ByteBuffer
void	write(byte[] block, long location) Writes the contents to the specified location.
void	write(java.nio.ByteBuffer[] blocks, long location) Writes the contents provided as array to the specified location.
void	write(java.nio.ByteBuffer block, long location) Writes the contents to the specified location.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MemMapFileAdapter

public MemMapFileAdapter(java.lang.String name,
                         java.lang.String mode)
                  throws java.io.FileNotFoundException,
                         java.io.IOException

Initializes the MemMapFileAdapter with file name and mode. It maps the file contents to the memory region.

Parameters:

name - file name

mode - opening mode (r, rw)

Throws:

java.io.FileNotFoundException - if file does not found

java.io.IOException

Method Detail

close

public void close()
           throws java.io.IOException

Closes the IO Adapter

Specified by:

close in interface IOAdapter

Throws:

java.io.IOException - if file operation fails

getFileLength

public long getFileLength()

Returns the length of the file

Specified by:

getFileLength in interface IOAdapter

Returns:

file length

read

public byte[] read(long location,
                   int length)
            throws java.io.IOException

Reads the contents and return it as byte array.

Specified by:

read in interface IOAdapter

Parameters:

location - location of the content in file

length - length of the content to read from the specified location

Returns:

contents in a byte array

Throws:

java.io.IOException

readFileAsBlocks

public java.nio.ByteBuffer[] readFileAsBlocks()
                                       throws java.io.IOException

Reads the entire contents of the file as ByteBuffer array.
The contents as divided as block based on the block size value

Specified by:

readFileAsBlocks in interface IOAdapter

Returns:

contents as ByteBuffer array

Throws:

java.io.IOException - if file operation fails

readIntoBuffer

public java.nio.ByteBuffer readIntoBuffer(long location)
                                   throws java.io.IOException

Reads the contents into the temporary buffer and returns it as ByteBuffer

Specified by:

readIntoBuffer in interface IOAdapter

Parameters:

location - location to be read

Returns:

contents as ByteBuffer

Throws:

java.io.IOException - if file operation fails

write

public void write(byte[] block,
                  long location)
           throws java.io.IOException

Writes the contents to the specified location.

Specified by:

write in interface IOAdapter

Parameters:

block - the content block as bytes

location - location to be written

Throws:

java.io.IOException - if file operation fails

write

public void write(java.nio.ByteBuffer[] blocks,
                  long location)
           throws java.io.IOException

Writes the contents provided as array to the specified location.

Specified by:

write in interface IOAdapter

Parameters:

blocks - contents as array of blocks

location - location to be written

Throws:

java.io.IOException - if file operation fails

write

public void write(java.nio.ByteBuffer block,
                  long location)
           throws java.io.IOException

Writes the contents to the specified location.

Specified by:

write in interface IOAdapter

Parameters:

block - the content block

location - location to be written

Throws:

java.io.IOException - if file operation fails