com.sun.hk2.component
Class SoftCache<K,V>

java.lang.Object
  com.sun.hk2.component.SoftCache<K,V>

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

A very primitive cache of at most one entry, that uses both SoftReference(s) to the key as well as the value it caches. Useful to provide minimal caching without imposing on heap.

Since:

3.1

Author:

Jeff Trent

Field Summary

protected java.lang.ref.SoftReference<K>	key
protected java.lang.ref.SoftReference<V>	value

Constructor Summary

SoftCache()

Method Summary

protected V	cacheValue(java.lang.ref.SoftReference<V> value2, V thisV)
void	clear() Clears the cache
V	get(K k, java.util.concurrent.Callable<V> callable) Returns either the cached value if hasn't been reclaimed by GC.
protected V	usingCacheValue(V thisV)

Methods inherited from class java.lang.Object

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

Field Detail

key

protected java.lang.ref.SoftReference<K> key

value

protected java.lang.ref.SoftReference<V> value

Constructor Detail

SoftCache

public SoftCache()

Method Detail

get

public V get(K k,
             java.util.concurrent.Callable<V> callable)

Returns either the cached value if hasn't been reclaimed by GC. Otherwise invokes the callable to refresh the cached value, and caching it again in the process.

Parameters:

key - the key; must be non-null

callable - the callable in case the cache is empty; must be non-null

Returns:

the value (either from cache or populated by the callable as a last resort)

cacheValue

protected V cacheValue(java.lang.ref.SoftReference<V> value2,
                       V thisV)

usingCacheValue

protected V usingCacheValue(V thisV)

clear

public void clear()

Clears the cache