info.aduna.gee.publication.servlets.util
Class MultiLevelExpiringCache

java.lang.Object
  info.aduna.gee.publication.servlets.util.MultiLevelExpiringCache

public class MultiLevelExpiringCache
extends Object

A multilevel maximum size cache. For the moment we implement a maximum of 3 keys. It's easy to extend it. Note: a MultiLevelExpiringCache can only be used with a constant number of keys. Either 1,2,3,4. You can't mix 1,2,3,4 get/put requests!

Field Summary

protected int	_currentSize We track the currentsize for efficiency
protected long	_insertCount The insertCount for a new put
protected int	_maxSize The maximum amount of Objects in the cache
protected long	_noSaves The number of protected "young" members of the Cache
protected HashMap	_theCache The cache

Constructor Summary

MultiLevelExpiringCache(int maxSize)

MultiLevelExpiringCache(int maxSize, int noSaves)
Create an expiring cache.

Method Summary

protected void	_cleanUp() Called by synchronized method.
protected void	_destroy(HashMap map)
protected void	_destroy(info.aduna.gee.publication.servlets.util.MultiLevelExpiringCache.MLEO mleo)
protected void	_destroy(Object o) Destroy an object or a branch of the tree cache.
protected info.aduna.gee.publication.servlets.util.MultiLevelExpiringCache.MLEO	_findEldest(HashMap map, info.aduna.gee.publication.servlets.util.MultiLevelExpiringCache.MLEO candidate) Called by synchronized method.
Object	_get(Object key1, Object key2, Object key3, Object key4, boolean unpackMleo) Get the object for the set of keys.
protected long	_priority(info.aduna.gee.publication.servlets.util.MultiLevelExpiringCache.MLEO mleo) The priority of an MLEO; it determines the sequence in which MLEO's are flushed from the cache.
protected int	_recalculateSize(HashMap map) Called by synchronized method.
protected boolean	_removeValue(HashMap parent, Object keyInParent, HashMap map, info.aduna.gee.publication.servlets.util.MultiLevelExpiringCache.MLEO mleo) Called by synchronized method
Object	get(Object key1)
Object	get(Object key1, Object key2)
Object	get(Object key1, Object key2, Object key3)
Object	get(Object key1, Object key2, Object key3, Object key4)
void	put(Object key1, Object value)
void	put(Object key1, Object key2, Object value)
void	put(Object key1, Object key2, Object key3, Object value)
void	put(Object key1, Object key2, Object key3, Object key4, Object value)
void	remove()
void	remove(Object key1)
void	remove(Object key1, Object key2)
void	remove(Object key1, Object key2, Object key3)
void	remove(Object key1, Object key2, Object key3, Object key4) Note: e.g.
int	size()

Methods inherited from class java.lang.Object

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

Field Detail

_theCache

protected HashMap _theCache

The cache

_currentSize

protected int _currentSize

We track the currentsize for efficiency

_insertCount

protected long _insertCount

The insertCount for a new put

_maxSize

protected int _maxSize

The maximum amount of Objects in the cache

_noSaves

protected long _noSaves

The number of protected "young" members of the Cache

Constructor Detail

MultiLevelExpiringCache

public MultiLevelExpiringCache(int maxSize)

MultiLevelExpiringCache

public MultiLevelExpiringCache(int maxSize,
                               int noSaves)

Create an expiring cache.

Parameters:

maxSize - the maximum total size of the cache

noSaves - the number of last inserted objects not to be removed when full.

Method Detail

get

public Object get(Object key1)

get

public Object get(Object key1,
                  Object key2)

get

public Object get(Object key1,
                  Object key2,
                  Object key3)

get

public Object get(Object key1,
                  Object key2,
                  Object key3,
                  Object key4)

_get

public Object _get(Object key1,
                   Object key2,
                   Object key3,
                   Object key4,
                   boolean unpackMleo)

Get the object for the set of keys.

Parameters:

upackMleo - if true return the stored Object, if false return the MLEO itself

put

public void put(Object key1,
                Object value)

put

public void put(Object key1,
                Object key2,
                Object value)

put

public void put(Object key1,
                Object key2,
                Object key3,
                Object value)

put

public void put(Object key1,
                Object key2,
                Object key3,
                Object key4,
                Object value)

remove

public void remove()

remove

public void remove(Object key1)

remove

public void remove(Object key1,
                   Object key2)

remove

public void remove(Object key1,
                   Object key2,
                   Object key3)

remove

public void remove(Object key1,
                   Object key2,
                   Object key3,
                   Object key4)

Note: e.g. in a four level MLEC, it is allowed to remove everything "below" either 1, 2, 3 or 4 keys. Note: objects that are removed are also destroyed!

size

public int size()

_recalculateSize

protected int _recalculateSize(HashMap map)

Called by synchronized method.

_cleanUp

protected void _cleanUp()

Called by synchronized method. Note: currently we always clean by 1.

_findEldest

protected info.aduna.gee.publication.servlets.util.MultiLevelExpiringCache.MLEO _findEldest(HashMap map,
                                                                                            info.aduna.gee.publication.servlets.util.MultiLevelExpiringCache.MLEO candidate)

Called by synchronized method.

_priority

protected long _priority(info.aduna.gee.publication.servlets.util.MultiLevelExpiringCache.MLEO mleo)

The priority of an MLEO; it determines the sequence in which MLEO's are flushed from the cache.

_removeValue

protected boolean _removeValue(HashMap parent,
                               Object keyInParent,
                               HashMap map,
                               info.aduna.gee.publication.servlets.util.MultiLevelExpiringCache.MLEO mleo)

Called by synchronized method

_destroy

protected void _destroy(info.aduna.gee.publication.servlets.util.MultiLevelExpiringCache.MLEO mleo)

_destroy

protected void _destroy(HashMap map)

_destroy

protected void _destroy(Object o)

Destroy an object or a branch of the tree cache.