org.apache.jackrabbit.core.state
Class MLRUItemStateCache

java.lang.Object
  org.apache.jackrabbit.core.state.MLRUItemStateCache

All Implemented Interfaces:

ItemStateCache

public class MLRUItemStateCache
extends Object
implements ItemStateCache

An ItemStateCache implementation that internally uses a LinkedMap to maintain a cache of ItemState objects. The cache uses a rough estimate of the memory consumption of the cached item states for calculating the maximum number of entries. The oldest entries are flushed once the cache size has exceeded a certain limit.

TODO rename class to something more appropriate, e.g. FIFOItemSateCache since it doesn't use a LRU eviction policy anymore.

Field Summary

static int

DEFAULT_MAX_MEM default maximum memory to use

Constructor Summary

MLRUItemStateCache(CacheManager cacheMgr)

Method Summary

void	cache(ItemState state) Stores the specified ItemState object in the map using its ItemId as the key.
void	dispose() Informs the cache that it is no longer in use.
void	evict(ItemId id) Removes the ItemState object with the specified id from this cache if it is present.
void	evictAll() Clears all entries from this cache.
boolean	isCached(ItemId id) Returns true if this cache contains an ItemState object with the specified id.
boolean	isEmpty() Returns true if this cache contains no entries.
ItemState	retrieve(ItemId id) Returns the ItemState object with the specified id if it is present or null if no entry exists with that id.
ItemState[]	retrieveAll() Returns all the cached item states.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_MAX_MEM

public static final int DEFAULT_MAX_MEM

default maximum memory to use

See Also:

Constant Field Values

Constructor Detail

MLRUItemStateCache

public MLRUItemStateCache(CacheManager cacheMgr)

Method Detail

isCached

public boolean isCached(ItemId id)

Returns true if this cache contains an ItemState object with the specified id.

Specified by:

isCached in interface ItemStateCache

Parameters:

id - id of ItemState object whose presence should be tested.

Returns:

true if there's a corresponding cache entry, otherwise false.

retrieve

public ItemState retrieve(ItemId id)

Returns the ItemState object with the specified id if it is present or null if no entry exists with that id.

Specified by:

retrieve in interface ItemStateCache

Parameters:

id - the id of the ItemState object to be returned.

Returns:

the ItemState object with the specified id or or null if no entry exists with that id

retrieveAll

public ItemState[] retrieveAll()

Returns all the cached item states.

Specified by:

retrieveAll in interface ItemStateCache

Returns:

newly allocated item state array

cache

public void cache(ItemState state)

Stores the specified ItemState object in the map using its ItemId as the key.

Specified by:

cache in interface ItemStateCache

Parameters:

state - the ItemState object to cache

evict

public void evict(ItemId id)

Removes the ItemState object with the specified id from this cache if it is present.

Specified by:

evict in interface ItemStateCache

Parameters:

id - the id of the ItemState object which should be removed from this cache.

evictAll

public void evictAll()

Clears all entries from this cache.

Specified by:

evictAll in interface ItemStateCache

isEmpty

public boolean isEmpty()

Returns true if this cache contains no entries.

Specified by:

isEmpty in interface ItemStateCache

Returns:

true if this cache contains no entries.

dispose

public void dispose()

Informs the cache that it is no longer in use.

Specified by:

dispose in interface ItemStateCache