net.eduvax.util

Class Cache<K,V>

java.lang.Object

net.eduvax.util.Cache<K,V>

public class Cache<K,V>
extends java.lang.Object

Simple object cache. This is a very simple cache : it does not deal with object in memory size but only store a fixed count of object, no matters with the size of objects. TODO : make it thread safe...

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Cache.LFU<K> Trivial LFU implementation.
static class	Cache.LRU<K> Default and trivial LRU implementation.
static class	Cache.Rand<K> Trivial Random cache strategy.

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.Hashtable<K,V>	_cachedObjs Cached objects
private int	_cSize cache current size
private DataSource<K,V>	_dataSource data source
private int	_maxSize cache max size
private CacheStrategy<K>	_strategy Cache management sstrategy.

Constructor Summary

Constructors

Constructor and Description
Cache(int size, DataSource<K,V> data) Create new cache usign defaults LRU strategy.
Cache(int size, DataSource<K,V> data, CacheStrategy<K> cs) Create new cache.

Method Summary

Methods

Modifier and Type	Method and Description
V	get(K key) retrieve one object in cache.
private void	init(int size, DataSource<K,V> data, CacheStrategy<K> cs) Cache initialisation
private void	insert(K key, V obj) insert object in cache.

Methods inherited from class java.lang.Object

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

Field Detail

_cachedObjs

private java.util.Hashtable<K,V> _cachedObjs

Cached objects

_strategy

private CacheStrategy<K> _strategy

Cache management sstrategy.

_cSize

private int _cSize

cache current size

_maxSize

private int _maxSize

cache max size

_dataSource

private DataSource<K,V> _dataSource

data source

Constructor Detail

Cache

public Cache(int size,
     DataSource<K,V> data)

Create new cache usign defaults LRU strategy.

Parameters:

size - cache size (max object count in cache).

data - data source

Cache

public Cache(int size,
     DataSource<K,V> data,
     CacheStrategy<K> cs)

Create new cache.

Parameters:

size - cache size (max object count in cache).

data - data source

strategy - Cache mangement strategy.

Method Detail

get

public V get(K key)

retrieve one object in cache. return object in cache or get it from data source if not yet cached.

Returns:

the object matching the key, null if not any.

insert

private void insert(K key,
          V obj)

insert object in cache. If cache is full, use strategy to determinate the object to remove from the cache.

init

private void init(int size,
        DataSource<K,V> data,
        CacheStrategy<K> cs)

Cache initialisation

Parameters:

size - cache size (max object count in cache).

data - data source

strategy - Cache mangement strategy.