com.bc.ceres.binio.util

Class MappedFileChannelIOHandler

java.lang.Object

com.bc.ceres.binio.util.MappedFileChannelIOHandler

All Implemented Interfaces:

IOHandler

public class MappedFileChannelIOHandler
extends Object
implements IOHandler

Constructor Summary

Constructors

Constructor and Description
MappedFileChannelIOHandler(FileChannel channel)

Method Summary

Modifier and Type	Method and Description
long	getMaxPosition() Returns the current size of the backing file, array or stream.
void	read(DataContext context, byte[] data, long position) Reads a sequence of up to data.length bytes into the given array starting from the the given position.
void	write(DataContext context, byte[] data, long position) Writes a sequence of up to data.length bytes to the file, starting at the given position.

Methods inherited from class java.lang.Object

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

Constructor Detail

MappedFileChannelIOHandler

public MappedFileChannelIOHandler(FileChannel channel)
                           throws IOException

Throws:

IOException

Method Detail

read

public void read(DataContext context,
                 byte[] data,
                 long position)
          throws IOException

Description copied from interface: IOHandler

Reads a sequence of up to data.length bytes into the given array starting from the the given position. If the position is greater than the file's current size then no bytes are read.

A read operation might not fill the array, and in fact it might not read any bytes at all. Whether or not it does so, depends upon the state of the file, e.g. only bytes that remain in the file starting from the given position will be read.

Specified by:

read in interface IOHandler

Parameters:

context - The I/O context.

data - The data array into which bytes are to be transferred.

position - The file position at which the transfer is to begin; must be non-negative.

Throws:

IOException - If an I/O error occurs.

write

public void write(DataContext context,
                  byte[] data,
                  long position)
           throws IOException

Description copied from interface: IOHandler

Writes a sequence of up to data.length bytes to the file, starting at the given position. If the given position is greater than the file's current size then the file will be grown to accommodate the new bytes; the values of any bytes between the previous end-of-file and the newly-written bytes are unspecified.

Specified by:

write in interface IOHandler

Parameters:

context - The I/O context.

data - The data array from which bytes are to be transferred.

position - The file position at which the transfer is to begin; must be non-negative.

Throws:

IOException - If an I/O error occurs.

getMaxPosition

public long getMaxPosition()
                    throws IOException

Description copied from interface: IOHandler

Returns the current size of the backing file, array or stream.

This value may change, while writing to a growing file or array. If the value is unknown -1 will be returned.

Specified by:

getMaxPosition in interface IOHandler

Returns:

Te maximum position.

Throws:

IOException - If an I/O error occurs.