org.apache.jcs.engine.memory
Class AbstractMemoryCache<K extends Serializable,V extends Serializable>

java.lang.Object
  org.apache.jcs.engine.memory.AbstractMemoryCache<K,V>

All Implemented Interfaces:

Serializable, IRequireScheduler, IMemoryCache<K,V>

Direct Known Subclasses:

AbstractDoubleLinkedListMemoryCache, LHMLRUMemoryCache

public abstract class AbstractMemoryCache<K extends Serializable,V extends Serializable>
extends Object
implements IMemoryCache<K,V>, Serializable, IRequireScheduler

This base includes some common code for memory 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

cacheName

protected String cacheName

The region name. This defines a namespace of sorts.

map

public Map<K extends Serializable,MemoryElementDescriptor<K extends Serializable,V extends Serializable>> map

Map where items are stored by key. This is created by the concrete child class.

elementAttributes

public IElementAttributes elementAttributes

Region Elemental Attributes, used as a default and copied for each item.

cacheAttributes

public ICompositeCacheAttributes cacheAttributes

Cache Attributes. Regions settings.

cache

public CompositeCache<K extends Serializable,V extends Serializable> cache

The cache region this store is associated with

status

protected CacheStatus status

status

chunkSize

protected int chunkSize

How many to spool at a time.

AbstractMemoryCache

public AbstractMemoryCache()

initialize

public void initialize(CompositeCache<K,V> hub)

For post reflection creation initialization

Specified by:

initialize in interface IMemoryCache<K extends Serializable,V extends Serializable>

Parameters:

hub -

setScheduledExecutorService

public void setScheduledExecutorService(ScheduledExecutorService scheduledExecutor)

Description copied from interface: IRequireScheduler

Inject an instance of a central ScheduledExecutorService

Specified by:

setScheduledExecutorService in interface IRequireScheduler

See Also:

IRequireScheduler.setScheduledExecutorService(java.util.concurrent.ScheduledExecutorService)

createMap

public abstract Map<K,MemoryElementDescriptor<K,V>> 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:

a threadsafe Map

remove

public abstract boolean remove(K key)
                        throws IOException

Removes an item from the cache

Specified by:

remove in interface IMemoryCache<K extends Serializable,V extends Serializable>

Parameters:

key - Identifies item to be removed

Returns:

Description of the Return Value

Throws:

IOException - Description of the Exception

get

public abstract ICacheElement<K,V> get(K key)
                                                                          throws IOException

Get an item from the cache

Specified by:

get in interface IMemoryCache<K extends Serializable,V extends Serializable>

Parameters:

key - Description of the Parameter

Returns:

Description of the Return Value

Throws:

IOException - Description of the Exception

getMultiple

public Map<K,ICacheElement<K,V>> getMultiple(Set<K> keys)
                                                                                                     throws IOException

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

Specified by:

getMultiple in interface IMemoryCache<K extends Serializable,V extends Serializable>

Parameters:

keys -

Returns:

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

Throws:

IOException

getQuiet

public ICacheElement<K,V> getQuiet(K key)
                                                                      throws IOException

Get an item from the cache without affecting its last access time or position. Not all memory cache implementations can get quietly.

Specified by:

getQuiet in interface IMemoryCache<K extends Serializable,V extends Serializable>

Parameters:

key - Identifies item to find

Returns:

Element matching key if found, or null

Throws:

IOException

update

public abstract void update(ICacheElement<K,V> ce)
                     throws IOException

Puts an item to the cache.

Specified by:

update in interface IMemoryCache<K extends Serializable,V extends Serializable>

Parameters:

ce - Description of the Parameter

Throws:

IOException - Description of the Exception

getKeySet

public abstract Set<K> getKeySet()

Get a set of the keys for all elements in the memory cache

Specified by:

getKeySet in interface IMemoryCache<K extends Serializable,V extends Serializable>

Returns:

A set of the key type

removeAll

public void removeAll()
               throws IOException

Removes all cached items from the cache.

Specified by:

removeAll in interface IMemoryCache<K extends Serializable,V extends Serializable>

Throws:

IOException

dispose

public void dispose()
             throws IOException

Prepares for shutdown.

Specified by:

dispose in interface IMemoryCache<K extends Serializable,V extends Serializable>

Throws:

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<K extends Serializable,V extends Serializable>

Returns:

statistics about the cache

getSize

public int getSize()

Returns the current cache size.

Specified by:

getSize in interface IMemoryCache<K extends Serializable,V extends Serializable>

Returns:

The size value

getStatus

public CacheStatus getStatus()

Returns the cache status.

Returns:

The status value

getCacheName

public String getCacheName()

Returns the cache (aka "region") name.

Returns:

The cacheName value

waterfal

public void waterfal(ICacheElement<K,V> ce)
              throws IOException

Puts an item to the cache.

Specified by:

waterfal in interface IMemoryCache<K extends Serializable,V extends Serializable>

Parameters:

ce -

Throws:

IOException

getIterator

public Iterator<Map.Entry<K,MemoryElementDescriptor<K,V>>> getIterator()

Gets the iterator attribute of the LRUMemoryCache object

Specified by:

getIterator in interface IMemoryCache<K extends Serializable,V extends Serializable>

Returns:

The iterator value

dumpMap

public void dumpMap()

Dump the cache map for debugging.

getCacheAttributes

public ICompositeCacheAttributes getCacheAttributes()

Returns the CacheAttributes.

Specified by:

getCacheAttributes in interface IMemoryCache<K extends Serializable,V extends Serializable>

Returns:

The CacheAttributes value

setCacheAttributes

public void setCacheAttributes(ICompositeCacheAttributes cattr)

Sets the CacheAttributes.

Specified by:

setCacheAttributes in interface IMemoryCache<K extends Serializable,V extends Serializable>

Parameters:

cattr - The new CacheAttributes value

getCompositeCache

public CompositeCache<K,V> getCompositeCache()

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

Specified by:

getCompositeCache in interface IMemoryCache<K extends Serializable,V extends Serializable>

Returns:

The cache value

getGroupKeys

public Set<K> getGroupKeys(String groupName)

Description copied from interface: IMemoryCache

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

Specified by:

getGroupKeys in interface IMemoryCache<K extends Serializable,V extends Serializable>

Parameters:

groupName -

Returns:

group keys

getGroupNames

public Set<String> getGroupNames()

Gets the set of group names in the cache

Specified by:

getGroupNames in interface IMemoryCache<K extends Serializable,V extends Serializable>

Returns:

a Set of group names.