org.apache.jcs.engine.memory

Class AbstractMemoryCache

java.lang.Object

org.apache.jcs.engine.memory.AbstractMemoryCache

All Implemented Interfaces:

java.io.Serializable, IMemoryCache, MemoryCache

Direct Known Subclasses:

AbstractDoulbeLinkedListMemoryCache

public abstract class AbstractMemoryCache
extends java.lang.Object
implements MemoryCache, java.io.Serializable

Some common code for the LRU and MRU caches.

This keeps a static reference to a memory shrinker clock daemon. If this region is configured to use the shrinker, the clock daemon will be setup to run the shrinker on this region.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
IElementAttributes	attr Region Elemental Attributes, used as a default.
protected CompositeCache	cache The cache region this store is associated with
protected java.lang.String	cacheName The region name.
ICompositeCacheAttributes	cattr Cache Attributes
protected int	chunkSize How many to spool at a time.
protected java.util.Map	map Map where items are stored by key
protected int	status status

Constructor Summary

Constructors

Constructor and Description
AbstractMemoryCache()

Method Summary

Methods

Modifier and Type	Method and Description
abstract java.util.Map	createMap() Children must implement this method.
void	dispose() Prepares for shutdown.
abstract ICacheElement	get(java.io.Serializable key) Get an item from the cache
ICompositeCacheAttributes	getCacheAttributes() Returns the CacheAttributes.
java.lang.String	getCacheName() Returns the cache name.
CompositeCache	getCompositeCache() Gets the cache hub / region that the MemoryCache is used by
java.util.Set	getGroupKeys(java.lang.String groupName) Gets the set of keys of objects currently in the group.
java.util.Iterator	getIterator() Gets the iterator attribute of the LRUMemoryCache object
abstract java.lang.Object[]	getKeyArray() Get an Array of the keys for all elements in the memory cache
java.util.Map	getMultiple(java.util.Set keys) Gets multiple items from the cache based on the given set of keys.
ICacheElement	getQuiet(java.io.Serializable key) Get an item from the cache without affecting its last access time or position.
int	getSize() Returns the current cache size.
IStats	getStatistics() Returns the historical and statistical data for a region's memory cache.
int	getStatus() Returns the cache status.
void	initialize(CompositeCache hub) For post reflection creation initialization
abstract boolean	remove(java.io.Serializable key) Removes an item from the cache
void	removeAll() Removes all cached items from the cache.
void	setCacheAttributes(ICompositeCacheAttributes cattr) Sets the CacheAttributes.
abstract void	update(ICacheElement ce) Puts an item to the cache.
void	waterfal(ICacheElement ce) Puts an item to the cache.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.jcs.engine.memory.behavior.IMemoryCache

freeElements

Field Detail

cacheName

protected java.lang.String cacheName

The region name. This defines a namespace of sorts.

map

protected java.util.Map map

Map where items are stored by key

attr

public IElementAttributes attr

Region Elemental Attributes, used as a default.

cattr

public ICompositeCacheAttributes cattr

Cache Attributes

cache

protected CompositeCache cache

The cache region this store is associated with

status

protected int status

status

chunkSize

protected int chunkSize

How many to spool at a time.

Constructor Detail

AbstractMemoryCache

public AbstractMemoryCache()

Method Detail

initialize

public void initialize(CompositeCache hub)

For post reflection creation initialization

Specified by:

initialize in interface IMemoryCache

Parameters:

hub -

createMap

public abstract java.util.Map createMap()

Children must implement this method. A FIFO implementation may use a tree map. An LRU might use a hashtable. The map returned should be threadsafe.

Returns:

Map

remove

public abstract boolean remove(java.io.Serializable key)
                        throws java.io.IOException

Removes an item from the cache

Specified by:

remove in interface IMemoryCache

Parameters:

key - Identifies item to be removed

Returns:

Description of the Return Value

Throws:

java.io.IOException - Description of the Exception

get

public abstract ICacheElement get(java.io.Serializable key)
                           throws java.io.IOException

Get an item from the cache

Specified by:

get in interface IMemoryCache

Parameters:

key - Description of the Parameter

Returns:

Description of the Return Value

Throws:

java.io.IOException - Description of the Exception

getMultiple

public java.util.Map getMultiple(java.util.Set keys)
                          throws java.io.IOException

Gets multiple items from the cache based on the given set of keys.

Specified by:

getMultiple in interface IMemoryCache

Parameters:

keys -

Returns:

a map of Serializable key to ICacheElement element, or an empty map if there is no data in cache for any of these keys

Throws:

java.io.IOException

getQuiet

public ICacheElement getQuiet(java.io.Serializable key)
                       throws java.io.IOException

Get an item from the cache without affecting its last access time or position.

Specified by:

getQuiet in interface IMemoryCache

Parameters:

key - Identifies item to find

Returns:

Element matching key if found, or null

Throws:

java.io.IOException

update

public abstract void update(ICacheElement ce)
                     throws java.io.IOException

Puts an item to the cache.

Specified by:

update in interface IMemoryCache

Parameters:

ce - Description of the Parameter

Throws:

java.io.IOException - Description of the Exception

getKeyArray

public abstract java.lang.Object[] getKeyArray()

Get an Array of the keys for all elements in the memory cache

Specified by:

getKeyArray in interface IMemoryCache

Returns:

An Object[]

removeAll

public void removeAll()
               throws java.io.IOException

Removes all cached items from the cache.

Specified by:

removeAll in interface IMemoryCache

Throws:

java.io.IOException

dispose

public void dispose()
             throws java.io.IOException

Prepares for shutdown.

Specified by:

dispose in interface IMemoryCache

Throws:

java.io.IOException

getStatistics

public IStats getStatistics()

Description copied from interface: IMemoryCache

Returns the historical and statistical data for a region's memory cache.

Specified by:

getStatistics in interface IMemoryCache

Returns:

statistics about the cache

getSize

public int getSize()

Returns the current cache size.

Specified by:

getSize in interface IMemoryCache

Returns:

The size value

getStatus

public int getStatus()

Returns the cache status.

Returns:

The status value

getCacheName

public java.lang.String getCacheName()

Returns the cache name.

Returns:

The cacheName value

waterfal

public void waterfal(ICacheElement ce)
              throws java.io.IOException

Puts an item to the cache.

Specified by:

waterfal in interface IMemoryCache

Parameters:

ce -

Throws:

java.io.IOException

getIterator

public java.util.Iterator getIterator()

Gets the iterator attribute of the LRUMemoryCache object

Specified by:

getIterator in interface IMemoryCache

Returns:

The iterator value

getCacheAttributes

public ICompositeCacheAttributes getCacheAttributes()

Returns the CacheAttributes.

Specified by:

getCacheAttributes in interface IMemoryCache

Returns:

The CacheAttributes value

setCacheAttributes

public void setCacheAttributes(ICompositeCacheAttributes cattr)

Sets the CacheAttributes.

Specified by:

setCacheAttributes in interface IMemoryCache

Parameters:

cattr - The new CacheAttributes value

getCompositeCache

public CompositeCache getCompositeCache()

Gets the cache hub / region that the MemoryCache is used by

Specified by:

getCompositeCache in interface IMemoryCache

Returns:

The cache value

getGroupKeys

public java.util.Set getGroupKeys(java.lang.String groupName)

Description copied from interface: IMemoryCache

Gets the set of keys of objects currently in the group.

Specified by:

getGroupKeys in interface IMemoryCache

Parameters:

groupName -

Returns:

group keys