edu.northwestern.at.utils.cache

Class OldLRUCache<K,V>

java.lang.Object

edu.northwestern.at.utils.cache.OldLRUCache<K,V>

All Implemented Interfaces:

Cache<K,V>

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

Fixed maximum size cache employing least-recently used method to age entries.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	OldLRUCache.Node

Field Summary

Fields

Modifier and Type	Field and Description
protected SoftReferenceCache<K,OldLRUCache.Node>	cache SoftReferenceCache which holds actual cached entries.
protected OldLRUCache.Node	head
protected int	maxEntries
protected OldLRUCache.Node	tail

Constructor Summary

Constructors

Constructor and Description
OldLRUCache(int maxEntries) Create a new cache.

Method Summary

Methods

Modifier and Type	Method and Description
void	clear() Clear all entries in the cache.
boolean	containsKey(K key) True if cache contains a specified key.
protected boolean	deleteLeastRecentlyUsed()
V	get(K key) Retrieve a cached value.
int	getMaxSize() Returns the maximum number of items allowed in the cache.
protected void	insertNode(OldLRUCache.Node node)
V	put(K key, V value) Add or replace a cached value.
V	remove(K key) Remove a specific entry from the cache.
protected void	removeNode(OldLRUCache.Node node)
int	size() Return current size of cache.

Methods inherited from class java.lang.Object

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

Field Detail

maxEntries

protected int maxEntries

cache

protected SoftReferenceCache<K,OldLRUCache.Node> cache

SoftReferenceCache which holds actual cached entries.

head

protected OldLRUCache.Node head

tail

protected OldLRUCache.Node tail

Constructor Detail

OldLRUCache

public OldLRUCache(int maxEntries)

Create a new cache.

Parameters:

maxEntries - Maximum number of entries allowed.

Method Detail

clear

public void clear()

Clear all entries in the cache.

Specified by:

clear in interface Cache<K,V>

containsKey

public boolean containsKey(K key)

True if cache contains a specified key.

Specified by:

containsKey in interface Cache<K,V>

Parameters:

key - The key to look up.

Returns:

true if the cache contains the key.

getMaxSize

public int getMaxSize()

Returns the maximum number of items allowed in the cache.

Returns:

Maximum number of entries allowed in cache.

get

public V get(K key)

Retrieve a cached value.

Specified by:

get in interface Cache<K,V>

Parameters:

key - The key of the entry to retrieve.

Returns:

The value of the cached entry specified by key; null if the cache does not contain the key.

put

public V put(K key,
    V value)

Add or replace a cached value.

Specified by:

put in interface Cache<K,V>

Parameters:

key - The key of the entry to add.

value - The value of the entry to add.

Returns:

The value of any existing cached entry specified by the key; null if the cache does not contain the key.

remove

public V remove(K key)

Remove a specific entry from the cache.

Specified by:

remove in interface Cache<K,V>

Parameters:

key - The key of the entry to remove.

Returns:

The entry removed, or null if none.

size

public int size()

Return current size of cache.

Specified by:

size in interface Cache<K,V>

Returns:

Number of entries (keys) currently stored in cache.

deleteLeastRecentlyUsed

protected boolean deleteLeastRecentlyUsed()

insertNode

protected void insertNode(OldLRUCache.Node node)

removeNode

protected void removeNode(OldLRUCache.Node node)