Package org.apache.oro.util

Class CacheLRU

java.lang.Object

org.apache.oro.util.GenericCache

org.apache.oro.util.CacheLRU

All Implemented Interfaces:

java.io.Serializable, Cache

public final class CacheLRU
extends GenericCache

This class is a GenericCache subclass implementing an LRU (Least Recently Used) cache replacement policy. In other words, values are added to the cache until it becomes full. Once the cache is full, when a new value is added to the cache, it replaces the least recently used value currently in the cache. This is probably the best general purpose cache replacement policy.

Since:

1.0

See Also:

GenericCache, Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
private int	__head
private int[]	__next
private int[]	__prev
private int	__tail
private static long	serialVersionUID

Fields inherited from class org.apache.oro.util.GenericCache

_cache, _numEntries, _table, DEFAULT_CAPACITY

Constructor Summary

Constructors

Constructor	Description
CacheLRU()	Same as:
CacheLRU(int capacity)	Creates a CacheLRU instance with a given cache capacity.

Method Summary

Modifier and Type	Method	Description
private void	__moveToFront(int index)
void	addElement(java.lang.Object key, java.lang.Object value)	Adds a value to the cache.
java.lang.Object	getElement(java.lang.Object key)	Gets an element from the cache.

Methods inherited from class org.apache.oro.util.GenericCache

capacity, isFull, keys, size

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

__head

private int __head

__tail

private int __tail

__next

private final int[] __next

__prev

private final int[] __prev

Constructor Detail

CacheLRU

public CacheLRU(int capacity)

Creates a CacheLRU instance with a given cache capacity.

Parameters:

capacity - The capacity of the cache.

CacheLRU

public CacheLRU()

Same as:

 CacheLRU(GenericCache.DEFAULT_CAPACITY);
 

Method Detail

__moveToFront

private void __moveToFront(int index)

getElement

public java.lang.Object getElement(java.lang.Object key)

Description copied from interface: Cache

Gets an element from the cache.

Specified by:

getElement in interface Cache

Overrides:

getElement in class GenericCache

Parameters:

key - Key

Returns:

Element value

addElement

public final void addElement(java.lang.Object key,
                             java.lang.Object value)

Adds a value to the cache. If the cache is full, when a new value is added to the cache, it replaces the least recently used value in the cache (i.e., LRU).

Specified by:

addElement in interface Cache

Specified by:

addElement in class GenericCache

Parameters:

key - The key referencing the value added to the cache.

value - The value to add to the cache.