org.apache.felix.eventadmin.impl.util

Class LeastRecentlyUsedCacheMap

java.lang.Object

org.apache.felix.eventadmin.impl.util.LeastRecentlyUsedCacheMap

All Implemented Interfaces:

CacheMap

public class LeastRecentlyUsedCacheMap
extends Object
implements CacheMap

This class implements a least recently used cache map. It will hold a given size of key-value pairs and drop the least recently used entry once this size is reached. This class is thread safe.

Author:

Felix Project Team

See Also:

CacheMap

Constructor Summary

Constructors

Constructor and Description
LeastRecentlyUsedCacheMap(int maxSize) The constructor of the cache.

Method Summary

Methods

Modifier and Type	Method and Description
void	add(Object key, Object value) Add the key-value pair to the cache.
void	clear() Remove all entries from the cache.
Object	get(Object key) Returns the value for the key in case there is one.
Object	remove(Object key) Remove the entry denoted by key from the cache and return its value.
int	size() Return the current size of the cache.

Methods inherited from class java.lang.Object

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

Constructor Detail

LeastRecentlyUsedCacheMap

public LeastRecentlyUsedCacheMap(int maxSize)

The constructor of the cache. The given max size will be used to determine the size of the cache that triggers replacing least recently used entries with new ones.

Parameters:

maxSize - The max number of entries in the cache

Method Detail

get

public Object get(Object key)

Returns the value for the key in case there is one. Additionally, the LRU counter for the key is updated.

Specified by:

get in interface CacheMap

Parameters:

key - The key for the value to return

Returns:

The value of the key in case there is one, null otherwise

See Also:

CacheMap.get(java.lang.Object)

add

public void add(Object key,
       Object value)

Add the key-value pair to the cache. The key will be come the most recently used entry. In case max size is (or has been) reached this will remove the least recently used entry in the cache. In case that the cache already contains this specific key-value pair it LRU counter is updated only.

Specified by:

add in interface CacheMap

Parameters:

key - The key for the value

value - The value for the key

See Also:

CacheMap.add(java.lang.Object, java.lang.Object)

remove

public Object remove(Object key)

Remove the entry denoted by key from the cache and return its value.

Specified by:

remove in interface CacheMap

Parameters:

key - The key of the entry to be removed

Returns:

The value of the entry removed, null if none

See Also:

CacheMap.remove(java.lang.Object)

size

public int size()

Return the current size of the cache.

Specified by:

size in interface CacheMap

Returns:

The number of entries currently in the cache.

See Also:

CacheMap.size()

clear

public void clear()

Remove all entries from the cache.

Specified by:

clear in interface CacheMap

See Also:

CacheMap.clear()