/** * $RCSfile: CacheObject.java,v $ * $Revision: 1.1 $ * $Date: 2002/06/24 18:36:10 $ * * Copyright (C) 1999-2001 CoolServlets, Inc. All rights reserved. * * This software is the proprietary information of CoolServlets, Inc. * Use is subject to license terms. */package com.struts2.framework.util;/** * Wrapper for all objects put into cache. It's primary purpose is to maintain * references to the linked lists that maintain the creation time of the object * and the ordering of the most used objects. * * This class is optimized for speed rather than strictly correct encapsulation. */public final class CacheObject {   /**    * Underlying object wrapped by the CacheObject.    */    public Object object;    /**     * The size of the Cacheable object. The size of the Cacheable     * object is only computed once when it is added to the cache. This makes     * the assumption that once objects are added to cache, they are mostly     * read-only and that their size does not change significantly over time.     */    public int size;    /**     * A reference to the node in the cache order list. We keep the reference     * here to avoid linear scans of the list. Every time the object is     * accessed, the node is removed from its current spot in the list and     * moved to the front.     */    public LinkedListNode lastAccessedListNode;    /**     * A reference to the node in the age order list. We keep the reference     * here to avoid linear scans of the list. The reference is used if the     * object has to be deleted from the list.     */    public LinkedListNode ageListNode;    /**     * A count of the number of times the object has been read from cache.     */    public int readCount = 0;    /**     * Creates a new cache object wrapper. The size of the Cacheable object     * must be passed in in order to prevent another possibly expensive     * lookup by querying the object itself for its size.<p>     *     * @param object the underlying Object to wrap.     * @param size the size of the Cachable object in bytes.     */    public CacheObject(Object object, int size) {        this.object = object;        this.size = size;    }}