org.objectweb.perseus.cache.replacement.lib
Class AbstractReplacementManager

java.lang.Object
  org.objectweb.perseus.cache.replacement.lib.AbstractReplacementManager

All Implemented Interfaces:

CacheCapacityEventListener, ReplacementManager, UnbindManager

Direct Known Subclasses:

FIFOReplacementManager, LRUReplacementManager, MRUReplacementManager

public abstract class AbstractReplacementManager

extends java.lang.Object

implements ReplacementManager, CacheCapacityEventListener

This class is a common implementation of a ReplacementManager.

Author:

E.Bruneton

See Also:

FIFOReplacementManager, LRUReplacementManager, MRUReplacementManager

Field Summary

protected java.util.SortedSet	entries Sorted list of WeakReplaceableCacheEntry entries.
protected Logger	logger
protected java.util.HashMap	oid2wentry
protected java.lang.ref.ReferenceQueue	queue Queue used to register the weak references stored in the entries list.
protected UnbindManager	ub
static java.lang.String	UNBIND_MANAGER_BINDING

Constructor Summary

AbstractReplacementManager()

Method Summary

protected abstract void	add(ReplaceableCacheEntry entry)
void	addForReplacement(FixableCacheEntry entry)
void	adjustForReplacement(FixableCacheEntry entry) Called whenever an object has been accessed.
void	bindFc(java.lang.String s, java.lang.Object o)
void	cacheResized(CacheCapacityEvent event) The cache has been resized.
int	forceFree(int capacity) It forces the replacement manager to free CacheEntry instances from the cahce.
java.lang.String[]	listFc()
java.lang.Object	lookupFc(java.lang.String s)
void	removeForReplacement(java.lang.Object oid) This method is called by the CacheManager in order to signal that an entry has been really evicted.
protected abstract void	touch(ReplaceableCacheEntry entry)
java.util.Collection	unbind(CacheEntryFilter filter, boolean force) Evicts the entries which are accepted by the filter.
boolean	unbind(java.lang.Object oid, boolean force) It forces the replacement manager to unbind a CacheEntry instance from the cache.
java.util.Collection	unbindAll(java.util.Collection _oids, boolean force) Evicts instances from the cache.
void	unbindFc(java.lang.String s)
java.util.Collection	unbindUnfixed(boolean force) Try to evict unfixed instances.

Methods inherited from class java.lang.Object

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

Field Detail

UNBIND_MANAGER_BINDING

public static final java.lang.String UNBIND_MANAGER_BINDING

See Also:

Constant Field Values

ub

protected UnbindManager ub

entries

protected java.util.SortedSet entries

Sorted list of WeakReplaceableCacheEntry entries. Each entry must have a unique age, so that this sorted set behaves as a sorted list.

oid2wentry

protected java.util.HashMap oid2wentry

queue

protected java.lang.ref.ReferenceQueue queue

Queue used to register the weak references stored in the entries list.

logger

protected Logger logger

Constructor Detail

AbstractReplacementManager

public AbstractReplacementManager()

Method Detail

listFc

public java.lang.String[] listFc()

lookupFc

public java.lang.Object lookupFc(java.lang.String s)

bindFc

public void bindFc(java.lang.String s,
                   java.lang.Object o)

unbindFc

public void unbindFc(java.lang.String s)

cacheResized

public void cacheResized(CacheCapacityEvent event)

Description copied from interface: CacheCapacityEventListener

The cache has been resized.

Specified by:

cacheResized in interface CacheCapacityEventListener

Parameters:

event - contains the old and the new cache size.

addForReplacement

public void addForReplacement(FixableCacheEntry entry)
                       throws CacheException

Specified by:

addForReplacement in interface ReplacementManager

Parameters:

entry - The cache entry that has been accessed.

Throws:

CacheException - Whenever an internal error occurs.

adjustForReplacement

public void adjustForReplacement(FixableCacheEntry entry)
                          throws CacheException

Description copied from interface: ReplacementManager

Called whenever an object has been accessed. Thus, this method, gives hints about recency/frequency of use. This hints are used within the replacement algorithm.

Specified by:

adjustForReplacement in interface ReplacementManager

Parameters:

entry - The cache entry that has been accessed.

Throws:

CacheException - Whenever an internal error occurs.

forceFree

public int forceFree(int capacity)
              throws CacheException

Description copied from interface: ReplacementManager

It forces the replacement manager to free CacheEntry instances from the cahce.

Specified by:

forceFree in interface ReplacementManager

Parameters:

capacity - is the quantity of space required by the cache.

Throws:

CacheException

removeForReplacement

public void removeForReplacement(java.lang.Object oid)

Description copied from interface: ReplacementManager

This method is called by the CacheManager in order to signal that an entry has been really evicted. In fact the eviction has been previously requested by the ReplacementManager, and now the GC garbaged an entry.

Specified by:

removeForReplacement in interface ReplacementManager

Parameters:

oid - is the evicted cache entry

unbind

public java.util.Collection unbind(CacheEntryFilter filter,
                                   boolean force)
                            throws CacheException

Description copied from interface: UnbindManager

Evicts the entries which are accepted by the filter.

Specified by:

unbind in interface UnbindManager

Parameters:

filter - is a cacheentry filter indicating wich entry has to be evicted

force - is a boolean value indicating if the cache must remove the entries or let the GC does its job.

Returns:

the collection of cache entry identifier really evicted.

Throws:

CacheException

unbindAll

public java.util.Collection unbindAll(java.util.Collection _oids,
                                      boolean force)
                               throws CacheException

Description copied from interface: UnbindManager

Evicts instances from the cache.

Specified by:

unbindAll in interface UnbindManager

Parameters:

_oids - is a collection of the identifier associated to cache entries to evict

force - is a boolean value indicating if the cache must remove the entries or let the GC does its job.

Returns:

the oid of the really evicted entries

Throws:

CacheException - is raised when entries are already unbound from the cache.

unbindUnfixed

public java.util.Collection unbindUnfixed(boolean force)
                                   throws CacheException

Description copied from interface: UnbindManager

Try to evict unfixed instances.

Specified by:

unbindUnfixed in interface UnbindManager

Parameters:

force - is a boolean value indicating if the cache must remove the entries or let the GC does its job.

Returns:

the number of entry really evicted

Throws:

CacheException

unbind

public boolean unbind(java.lang.Object oid,
                      boolean force)
               throws CacheException

It forces the replacement manager to unbind a CacheEntry instance from the cache.

Specified by:

unbind in interface UnbindManager

Parameters:

oid - is the identifier associated to the cache entry to evict

force - is a boolean value indicating if the cache must remove the entry or let the GC does its job.

Throws:

CacheException - is raised when the entry is already unbound from the cache.

add

protected abstract void add(ReplaceableCacheEntry entry)

touch

protected abstract void touch(ReplaceableCacheEntry entry)