com.sun.ejb.containers.util.cache
Class LruCache

java.lang.Object
  com.sun.ejb.containers.util.cache.BaseCache
      com.sun.ejb.containers.util.cache.LruCache

All Implemented Interfaces:

Cache

Direct Known Subclasses:

FIFOEJBObjectCache, LruSessionCache, PassivatedSessionCache

public class LruCache
extends BaseCache

LRUCache in-memory bounded cache with an LRU list

Nested Class Summary

protected static class

LruCache.LruCacheItem default CacheItem class implementation

Nested classes/interfaces inherited from class com.sun.ejb.containers.util.cache.BaseCache

BaseCache.CacheItem

Field Summary

protected static java.util.logging.Logger	_logger
protected java.lang.String	cacheName
protected LruCache.LruCacheItem	head
protected int	listSize
static long	NO_TIMEOUT
protected LruCache.LruCacheItem	tail
protected long	timeout
protected int	trimCount

Fields inherited from class com.sun.ejb.containers.util.cache.BaseCache

_rb, addCount, addCountLk, bucketLocks, buckets, entryCount, entryCountLk, hitCount, hitCountLk, listeners, maxBuckets, missCount, missCountLk, overflowCount, overflowCountLk, refreshCount, refreshCountLk, refreshFlags, removalCount, removalCountLk, threshold

Constructor Summary

LruCache()
default constructor

LruCache(long timeout)
constructor with specified timeout

Method Summary

protected BaseCache.CacheItem	createItem(int hashCode, java.lang.Object key, java.lang.Object value, int size) create new item
java.lang.Object	getStatByName(java.lang.String key) get the desired statistic counter
java.util.Map	getStats() get the stats snapshot
protected void	itemAccessed(BaseCache.CacheItem item) this item is accessed
protected BaseCache.CacheItem	itemAdded(BaseCache.CacheItem item) /** this item is just added to the cache
protected void	itemRefreshed(BaseCache.CacheItem item, int oldSize) item value has been refreshed
protected void	itemRemoved(BaseCache.CacheItem item) item value has been removed from the cache
void	setCacheName(java.lang.String name)
void	trimExpiredEntries(int maxCount) trim the expired entries from the cache.
protected BaseCache.CacheItem	trimLru(long currentTime) trim one item from the LRU list

Methods inherited from class com.sun.ejb.containers.util.cache.BaseCache

_put, _remove, _removeItem, add, add, addCacheListener, clear, clearStats, contains, decrementEntryCount, destroy, elements, eq, get, get, getAll, getEntryCount, getIndex, getIndex, handleOverflow, hash, incrementAddCount, incrementEntryCount, incrementHitCount, incrementMissCount, incrementOverflowCount, incrementRefreshCount, incrementRemovalCount, init, init, isEmpty, isThresholdReached, keys, loadValue, notifyRefresh, put, put, remove, remove, remove, removeAll, trimItem, values, waitRefresh

Methods inherited from class java.lang.Object

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

Field Detail

_logger

protected static final java.util.logging.Logger _logger

cacheName

protected java.lang.String cacheName

NO_TIMEOUT

public static final long NO_TIMEOUT

See Also:

Constant Field Values

head

protected LruCache.LruCacheItem head

tail

protected LruCache.LruCacheItem tail

trimCount

protected int trimCount

listSize

protected int listSize

timeout

protected long timeout

Constructor Detail

LruCache

public LruCache()

default constructor

LruCache

public LruCache(long timeout)

constructor with specified timeout

Method Detail

createItem

protected BaseCache.CacheItem createItem(int hashCode,
                                         java.lang.Object key,
                                         java.lang.Object value,
                                         int size)

create new item

Overrides:

createItem in class BaseCache

Parameters:

hashCode - for the entry

key - Object key

value - Object value

size - size in bytes of the item subclasses may override to provide their own CacheItem extensions e.g. one that permits persistence.

trimLru

protected BaseCache.CacheItem trimLru(long currentTime)

trim one item from the LRU list

Parameters:

currentTime - of this operation

Returns:

the item trimmed from cache list synchronization is handled by the caller

itemAdded

protected BaseCache.CacheItem itemAdded(BaseCache.CacheItem item)

/** this item is just added to the cache

Overrides:

itemAdded in class BaseCache

Parameters:

item - CacheItem that was created

Returns:

a overflow item; may be null this function checks if adding the new item results in a overflow; if so, it returns the item to be removed. Cache bucket is already synchronized by the caller

itemAccessed

protected void itemAccessed(BaseCache.CacheItem item)

this item is accessed

Overrides:

itemAccessed in class BaseCache

Parameters:

item - CacheItem accessed Cache bucket is already synchronized by the caller

itemRefreshed

protected void itemRefreshed(BaseCache.CacheItem item,
                             int oldSize)

item value has been refreshed

Overrides:

itemRefreshed in class BaseCache

Parameters:

item - CacheItem that was refreshed

oldSize - size of the previous value that was refreshed Cache bucket is already synchronized by the caller

itemRemoved

protected void itemRemoved(BaseCache.CacheItem item)

item value has been removed from the cache

Overrides:

itemRemoved in class BaseCache

Parameters:

item - CacheItem that was just removed Cache bucket is already synchronized by the caller

trimExpiredEntries

public void trimExpiredEntries(int maxCount)

trim the expired entries from the cache.

Specified by:

trimExpiredEntries in interface Cache

Overrides:

trimExpiredEntries in class BaseCache

Parameters:

maxCount - maximum number of invalid entries to trim specify Integer.MAX_VALUE to trim all invalid entries This call is to be scheduled by a thread managed by the container. NOTE: this algorithm assumes that all the entries in the cache have identical timeout (otherwise traversing from tail won't be right).

getStatByName

public java.lang.Object getStatByName(java.lang.String key)

get the desired statistic counter

Specified by:

getStatByName in interface Cache

Overrides:

getStatByName in class BaseCache

Parameters:

key - to corresponding stat

Returns:

an Object corresponding to the stat See also: Constant.java for the key

getStats

public java.util.Map getStats()

Description copied from class: BaseCache

get the stats snapshot

Specified by:

getStats in interface Cache

Overrides:

getStats in class BaseCache

Returns:

a Map of stats See also: Constant.java for the keys

setCacheName

public void setCacheName(java.lang.String name)