Package org.rostore.v2.media.block

Class MappedPhysicalBlocks

java.lang.Object

org.rostore.v2.media.block.MappedPhysicalBlocks

public class MappedPhysicalBlocks
extends Object

This is a container of all active physical blocks in the ro-store.

It manages a cache of the blocks, so that different processes would get the access to the same instances of the blocks.

When the blocks are not used by any processes they still be preserved in the cache until the time provided in MediaProperties.getCloseUnusedBlocksAfterMillis() is expired.

This passive caching is only applied for the non-data blocks, the blocks which type is not BlockType.DATA.

This is a major hub of blocks in the Media and this class manages the concurrent access and is internally is thread safe.

A great precaution should be paid to the synchronized blocks in its implementation.

Constructor Summary

Constructors

Constructor	Description
MappedPhysicalBlocks(Media media)	Creates an object

Method Summary

Modifier and Type	Method	Description
void	closeExpired()
void	closeUnused()
Block	get(BlockContainer blockContainer, long index, BlockType blockType)	Creates a BlockContainer private Block.
void	remove(BlockContainer blockContainer, long index)
int	size()	The total size of passively cached blocks and the actively used that are currently managed by this instance.

Methods inherited from class java.lang.Object

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

Constructor Details

MappedPhysicalBlocks

public MappedPhysicalBlocks(Media media)

Creates an object

Parameters:

media - the media it should be used in

Method Details

size

public int size()

The total size of passively cached blocks and the actively used that are currently managed by this instance.

Returns:

a number of blocks currently in the memory

get

public Block get(BlockContainer blockContainer,
 long index,
 BlockType blockType)

Creates a BlockContainer private Block. If the block is not in use or in cache, it is get loaded from the persistence layer.

Parameters:

blockContainer - the container the block should be associated with

index - the index of the block

blockType - the type of the block

Returns:

a block that can be used in the container

remove

public void remove(BlockContainer blockContainer,
 long index)

closeExpired

public void closeExpired()

closeUnused

public void closeUnused()