org.mmbase.cache.implementation
Class LRUCache<K,V>

java.lang.Object
  org.mmbase.cache.implementation.LRUCache<K,V>

All Implemented Interfaces:

Map<K,V>, CacheImplementationInterface<K,V>

public class LRUCache<K,V>
extends Object
implements CacheImplementationInterface<K,V>

A cache implementation backed by a LinkedHashMap, in access-order mode, and restricted maximal size ('Least Recently Used' cache algorithm).

Since:

MMBase-1.8.6

Version:

$Id: LRUCache.java 41943 2010-04-16 17:18:19Z michiel $

Author:

Michiel Meeuwissen

See Also:

Cache

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K,V>

Field Summary

int

maxSize

Constructor Summary

LRUCache()

LRUCache(int size)

Method Summary

void	clear()
void	config(Map<String,String> map) Configure the implementation with the given configuration values
boolean	containsKey(Object key)
boolean	containsValue(Object value)
Set<Map.Entry<K,V>>	entrySet()
V	get(Object key)
int	getCount(K key) Returns the hit-count on a certain key (if implementable, -1 otherwise).
Object	getLock() The cache implementation must be somehow thread-safe.
boolean	isEmpty()
Set<K>	keySet()
int	maxSize() Gets the (maximal) size of the cache (if implementable)
V	put(K key, V value)
void	putAll(Map<? extends K,? extends V> map)
V	remove(Object key)
void	setMaxSize(int size) Change the maximum size of the table.
int	size()
String	toString() Returns size, maxSize.
Collection<V>	values()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

equals, hashCode

Field Detail

maxSize

public int maxSize

Constructor Detail

LRUCache

public LRUCache()

LRUCache

public LRUCache(int size)

Method Detail

getCount

public int getCount(K key)

Description copied from interface: CacheImplementationInterface

Returns the hit-count on a certain key (if implementable, -1 otherwise).

Specified by:

getCount in interface CacheImplementationInterface<K,V>

setMaxSize

public void setMaxSize(int size)

Change the maximum size of the table. This may result in removal of entries in the table.

Specified by:

setMaxSize in interface CacheImplementationInterface<K,V>

Parameters:

size - the new desired size

maxSize

public final int maxSize()

Description copied from interface: CacheImplementationInterface

Gets the (maximal) size of the cache (if implementable)

Specified by:

maxSize in interface CacheImplementationInterface<K,V>

toString

public String toString()

Returns size, maxSize.

Overrides:

toString in class Object

config

public void config(Map<String,String> map)

Description copied from interface: CacheImplementationInterface

Configure the implementation with the given configuration values

Specified by:

config in interface CacheImplementationInterface<K,V>

getLock

public Object getLock()

Description copied from interface: CacheImplementationInterface

The cache implementation must be somehow thread-safe. This method should return the object on which to synchronize, e.g. when looping over entrySet.

Specified by:

getLock in interface CacheImplementationInterface<K,V>

size

public int size()

Specified by:

size in interface Map<K,V>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Map<K,V>

containsKey

public boolean containsKey(Object key)

Specified by:

containsKey in interface Map<K,V>

containsValue

public boolean containsValue(Object value)

Specified by:

containsValue in interface Map<K,V>

get

public V get(Object key)

Specified by:

get in interface Map<K,V>

put

public V put(K key,
             V value)

Specified by:

put in interface Map<K,V>

remove

public V remove(Object key)

Specified by:

remove in interface Map<K,V>

putAll

public void putAll(Map<? extends K,? extends V> map)

Specified by:

putAll in interface Map<K,V>

clear

public void clear()

Specified by:

clear in interface Map<K,V>

keySet

public Set<K> keySet()

Specified by:

keySet in interface Map<K,V>

entrySet

public Set<Map.Entry<K,V>> entrySet()

Specified by:

entrySet in interface Map<K,V>

values

public Collection<V> values()

Specified by:

values in interface Map<K,V>