net.sf.ehcache.store
Class LfuPolicy

java.lang.Object
  net.sf.ehcache.store.LfuPolicy

public final class LfuPolicy
extends java.lang.Object

Contains common LFU policy code for use between the LfuMemoryStore and the DiskStore, which also uses an LfuPolicy for evictions.

Version:

$Id: LfuPolicy.java 539 2007-08-15 08:05:59Z gregluck $

Author:

Greg Luck

Nested Class Summary

static interface

LfuPolicy.Metadata A type representing relevant metadata from an element, used by LfuPolicy for its operations.

Method Summary

static int[]	generateRandomSample(int populationSize) Generates a random sample from a population
static LfuPolicy.Metadata	leastHit(LfuPolicy.Metadata[] sampledElements, LfuPolicy.Metadata justAdded) Finds the least hit of the sampled elements provided

Methods inherited from class java.lang.Object

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

Method Detail

leastHit

public static LfuPolicy.Metadata leastHit(LfuPolicy.Metadata[] sampledElements,
                                          LfuPolicy.Metadata justAdded)

Finds the least hit of the sampled elements provided

Parameters:

sampledElements - this should be a random subset of the population

justAdded - we never want to select the element just added. May be null.

Returns:

the least hit

generateRandomSample

public static int[] generateRandomSample(int populationSize)

Generates a random sample from a population

Parameters:

populationSize - the size to draw from