uk.ac.starlink.fits

Class BlockManager

java.lang.Object

uk.ac.starlink.fits.BlockManager

public class BlockManager
extends Object

Manages access to a region of a file in blocks using multiple BufferManagers to cover it.

Since:

12 May 2022

Author:

Mark Taylor

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_BLOCKSIZE Default size of a block.

Constructor Summary

Constructors

Constructor and Description
BlockManager(FileChannel chan, long offset, long size, String logName, Unmapper unmapper, int blockSize) Constructor.

Method Summary

Modifier and Type	Method and Description
void	close() Closes all the BufferManagers maintained by this object.
int	getBlockCount() Returns the number of blocks used by this mananger.
int	getBlockSize() Returns the size of blocks used by this manager.
BufferManager	getBufferManager(int ib) Returns the BufferManager for a given block.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_BLOCKSIZE

public static final int DEFAULT_BLOCKSIZE

Default size of a block.

See Also:

Constant Field Values

Constructor Detail

BlockManager

public BlockManager(FileChannel chan,
                    long offset,
                    long size,
                    String logName,
                    Unmapper unmapper,
                    int blockSize)

Constructor.

Parameters:

chan - file channel

offset - offset into file of start of mapped region

size - length of mapped region

logName - description of mapped region suitable for use in logging messages

unmapper - used to unmap buffers, may be null for safety

blockSize - size of each block (except the last)

Method Detail

getBlockCount

public int getBlockCount()

Returns the number of blocks used by this mananger.

Returns:

block count

getBlockSize

public int getBlockSize()

Returns the size of blocks used by this manager. All blocks are the same size, except (probably) the last one, which may be shorter.

Returns:

block size

getBufferManager

public BufferManager getBufferManager(int ib)

Returns the BufferManager for a given block.

Parameters:

ib - block index

Returns:

buffer manager

close

public void close()

Closes all the BufferManagers maintained by this object. Only use when no buffers will be used any more.