freemarker.cache
Class MruCacheStorage

java.lang.Object
  freemarker.cache.MruCacheStorage

All Implemented Interfaces:

CacheStorage

public class MruCacheStorage
extends java.lang.Object
implements CacheStorage

A cache storage that implements a two-level Most Recently Used cache. In the first level, items are strongly referenced up to the specified maximum. When the maximum is exceeded, the least recently used item is moved into the second level cache, where they are softly referenced, up to another specified maximum. When the second level maximum is also exceeded, the least recently used item is discarded altogether. This cache storage is a generalization of both StrongCacheStorage and SoftCacheStorage - the effect of both of them can be achieved by setting one maximum to zero and the other to the largest positive integer. On the other hand, if you wish to use this storage in a strong-only mode, or in a soft-only mode, you might consider using StrongCacheStorage or SoftCacheStorage instead, as they can be used by TemplateCache concurrently without any synchronization on a 5.0 or later JRE. This class is NOT thread-safe. If it is accessed from multiple threads concurrently, proper synchronization must be provided by the callers. Note that TemplateCache, the natural user of this class provides the necessary synchronizations when it uses the class. Also you might consider whether you need this sort of a mixed storage at all in your solution, as in most cases SoftCacheStorage can also be sufficient. SoftCacheStorage will use Java soft references, and they already use access timestamps internally to bias the garbage collector against clearing recently used references, so you can get reasonably good (and memory-sensitive) most-recently-used caching through SoftCacheStorage as well.

Version:

$Id: MruCacheStorage.java,v 1.7.2.1 2007/04/02 13:07:32 szegedia Exp $

Author:

Attila Szegedi

Constructor Summary

MruCacheStorage(int maxStrongSize, int maxSoftSize)
Creates a new MRU cache storage with specified maximum cache sizes.

Method Summary

void	clear()
java.lang.Object	get(java.lang.Object key)
void	put(java.lang.Object key, java.lang.Object value)
void	remove(java.lang.Object key)

Methods inherited from class java.lang.Object

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

Constructor Detail

MruCacheStorage

public MruCacheStorage(int maxStrongSize,
                       int maxSoftSize)

Creates a new MRU cache storage with specified maximum cache sizes. Each cache size can vary between 0 and Integer.MAX_VALUE.

Parameters:

maxStrongSize - the maximum number of strongly referenced templates

maxSoftSize - the maximum number of softly referenced templates

Method Detail

get

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

Specified by:

get in interface CacheStorage

put

public void put(java.lang.Object key,
                java.lang.Object value)

Specified by:

put in interface CacheStorage

remove

public void remove(java.lang.Object key)

Specified by:

remove in interface CacheStorage

clear

public void clear()

Specified by:

clear in interface CacheStorage