org.h2.util

Class CacheLRU

java.lang.Object

org.h2.util.CacheLRU

All Implemented Interfaces:

Cache

public class CacheLRU
extends java.lang.Object
implements Cache

A cache implementation based on the last recently used (LRU) algorithm.

Method Summary

Modifier and Type	Method and Description
void	clear() Clear the cache.
CacheObject	find(int pos) Get an element from the cache if it is available.
CacheObject	get(int pos) Get an element in the cache if it is available.
java.util.ArrayList<CacheObject>	getAllChanged() Get all objects in the cache that have been changed.
static Cache	getCache(CacheWriter writer, java.lang.String cacheType, int cacheSize) Create a cache of the given type and size.
int	getMaxMemory() Get the maximum memory to be used.
int	getMemory() Get the used size in KB.
void	put(CacheObject rec) Add an element to the cache.
boolean	remove(int pos) Remove an object from the cache.
void	setMaxMemory(int maxKb) Set the maximum memory to be used by this cache.
CacheObject	update(int pos, CacheObject rec) Update an element in the cache.

Methods inherited from class java.lang.Object

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

Method Detail

getCache

public static Cache getCache(CacheWriter writer,
                             java.lang.String cacheType,
                             int cacheSize)

Create a cache of the given type and size.

Parameters:

writer - the cache writer

cacheType - the cache type

cacheSize - the size

Returns:

the cache object

clear

public void clear()

Description copied from interface: Cache

Clear the cache.

Specified by:

clear in interface Cache

put

public void put(CacheObject rec)

Description copied from interface: Cache

Add an element to the cache. Other items may fall out of the cache because of this. It is not allowed to add the same record twice.

Specified by:

put in interface Cache

Parameters:

rec - the object

update

public CacheObject update(int pos,
                          CacheObject rec)

Description copied from interface: Cache

Update an element in the cache. This will move the item to the front of the list.

Specified by:

update in interface Cache

Parameters:

pos - the unique key of the element

rec - the element

Returns:

the element

remove

public boolean remove(int pos)

Description copied from interface: Cache

Remove an object from the cache.

Specified by:

remove in interface Cache

Parameters:

pos - the unique key of the element

Returns:

true if the key was in the cache

find

public CacheObject find(int pos)

Description copied from interface: Cache

Get an element from the cache if it is available. This will not move the item to the front of the list.

Specified by:

find in interface Cache

Parameters:

pos - the unique key of the element

Returns:

the element or null

get

public CacheObject get(int pos)

Description copied from interface: Cache

Get an element in the cache if it is available. This will move the item to the front of the list.

Specified by:

get in interface Cache

Parameters:

pos - the unique key of the element

Returns:

the element or null

getAllChanged

public java.util.ArrayList<CacheObject> getAllChanged()

Description copied from interface: Cache

Get all objects in the cache that have been changed.

Specified by:

getAllChanged in interface Cache

Returns:

the list of objects

setMaxMemory

public void setMaxMemory(int maxKb)

Description copied from interface: Cache

Set the maximum memory to be used by this cache.

Specified by:

setMaxMemory in interface Cache

Parameters:

maxKb - the maximum size in KB

getMaxMemory

public int getMaxMemory()

Description copied from interface: Cache

Get the maximum memory to be used.

Specified by:

getMaxMemory in interface Cache

Returns:

the maximum size in KB

getMemory

public int getMemory()

Description copied from interface: Cache

Get the used size in KB.

Specified by:

getMemory in interface Cache

Returns:

the current size in KB