org.apache.shindig.common.cache
Class LruCache<K,V>

java.lang.Object
  java.util.AbstractMap<K,V>
      java.util.HashMap<K,V>
          java.util.LinkedHashMap<K,V>
              org.apache.shindig.common.cache.LruCache<K,V>

All Implemented Interfaces:

Serializable, Cloneable, Map<K,V>, Cache<K,V>

public class LruCache<K,V>
extends LinkedHashMap<K,V>
implements Cache<K,V>

A basic LRU cache. Prefer using EhCache for most purposes to this class.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class java.util.AbstractMap

AbstractMap.SimpleEntry<K,V>, AbstractMap.SimpleImmutableEntry<K,V>

Constructor Summary

LruCache(int capacity)

Method Summary

void	addElement(K key, V value) Stores an entry into the cache.
long	getCapacity() Returns the capacity of the cache.
V	getElement(K key) Retrieves an entry for the cache.
long	getSize()
protected boolean	removeEldestEntry(Map.Entry<K,V> eldest)
V	removeElement(K key) Removes an entry from the cache.

Methods inherited from class java.util.LinkedHashMap

clear, containsValue, get

Methods inherited from class java.util.HashMap

clone, containsKey, entrySet, isEmpty, keySet, put, putAll, remove, size, values

Methods inherited from class java.util.AbstractMap

equals, hashCode, toString

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Map

containsKey, entrySet, equals, hashCode, isEmpty, keySet, put, putAll, remove, size, values

Constructor Detail

LruCache

public LruCache(int capacity)

Method Detail

getElement

public V getElement(K key)

Description copied from interface: Cache

Retrieves an entry for the cache.

Specified by:

getElement in interface Cache<K,V>

Returns:

The entry stored under the given key, or null if it doesn't exist.

addElement

public void addElement(K key,
                       V value)

Description copied from interface: Cache

Stores an entry into the cache.

Specified by:

addElement in interface Cache<K,V>

removeElement

public V removeElement(K key)

Description copied from interface: Cache

Removes an entry from the cache.

Specified by:

removeElement in interface Cache<K,V>

Parameters:

key - The entry to return.

Returns:

The entry stored under the given key, or null if it doesn't exist.

getCapacity

public long getCapacity()

Description copied from interface: Cache

Returns the capacity of the cache.

Specified by:

getCapacity in interface Cache<K,V>

Returns:

a positive integer indicating the upper bound on the number of allowed elements in the cace, -1 signifies that the capacity is unbounded

getSize

public long getSize()

Specified by:

getSize in interface Cache<K,V>

Returns:

The current size of the cache, or -1 if the cache does not support returning sizes.

removeEldestEntry

protected boolean removeEldestEntry(Map.Entry<K,V> eldest)

Overrides:

removeEldestEntry in class LinkedHashMap<K,V>