org.neo4j.helpers.collection

Class LruCache<K,E>

java.lang.Object

org.neo4j.helpers.collection.LruCache<K,E>

public class LruCache<K,E>
extends Object

Simple implementation of Least-recently-used cache.

The cache has a maxSize set and when the number of cached elements exceeds that limit the least recently used element will be removed.

Constructor Summary

Constructors

Constructor and Description
LruCache(String name, int maxSize) Creates a LRU cache.

Method Summary

Modifier and Type	Method and Description
void	clear()
void	elementCleaned(E element)
E	get(K key)
String	getName()
Set<K>	keySet()
int	maxSize() Returns the maximum size of this cache.
void	put(K key, E element)
E	remove(K key)
void	resize(int newMaxSize) Changes the max size of the cache.
int	size()

Methods inherited from class java.lang.Object

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

Constructor Detail

LruCache

public LruCache(String name,
                int maxSize)

Creates a LRU cache. If maxSize < 1 an IllegalArgumentException is thrown.

Parameters:

name - name of cache

maxSize - maximum size of this cache

Method Detail

getName

public String getName()

maxSize

public int maxSize()

Returns the maximum size of this cache.

Returns:

maximum size

put

public void put(K key,
                E element)

remove

public E remove(K key)

get

public E get(K key)

clear

public void clear()

size

public int size()

keySet

public Set<K> keySet()

resize

public void resize(int newMaxSize)

Changes the max size of the cache. If newMaxSize is greater then maxSize() next invoke to maxSize() will return newMaxSize and the entries in cache will not be modified.

If newMaxSize is less then size() the cache will shrink itself removing least recently used element until size() equals newMaxSize. For each element removed the elementCleaned(E) method is invoked.

If newMaxSize is less then 1 an IllegalArgumentException is thrown.

Parameters:

newMaxSize - the new maximum size of the cache

elementCleaned

public void elementCleaned(E element)