jforum example source code file (PostRepository.java)

This example jforum source code file (PostRepository.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - jforum tags/keywords

arraylist, cache_size, cacheable, fqn, iterator, linkedhashmap, list, list, map, map, post, post, string, string, util

The jforum PostRepository.java source code

/*
 * Copyright (c) JForum Team
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, 
 * with or without modification, are permitted provided 
 * that the following conditions are met:
 * 
 * 1) Redistributions of source code must retain the above 
 * copyright notice, this list of conditions and the 
 * following  disclaimer.
 * 2)  Redistributions in binary form must reproduce the 
 * above copyright notice, this list of conditions and 
 * the following disclaimer in the documentation and/or 
 * other materials provided with the distribution.
 * 3) Neither the name of "Rafael Steil" nor 
 * the names of its contributors may be used to endorse 
 * or promote products derived from this software without 
 * specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT 
 * HOLDERS AND CONTRIBUTORS "AS IS" AND ANY 
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, 
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 
 * THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE 
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES 
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, 
 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER 
 * IN CONTRACT, STRICT LIABILITY, OR TORT 
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE
 * 
 * This file creation date: 07/02/2005 - 10:29:14
 * The JForum Project
 * http://www.jforum.net
 */
package net.jforum.repository;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import net.jforum.cache.CacheEngine;
import net.jforum.cache.Cacheable;
import net.jforum.dao.DataAccessDriver;
import net.jforum.dao.PostDAO;
import net.jforum.entities.Post;
import net.jforum.util.preferences.ConfigKeys;
import net.jforum.util.preferences.SystemGlobals;
import net.jforum.view.forum.common.PostCommon;

/**
 * Repository for the post in the top n topics for each forum.
 * 
 * @author Sean Mitchell
 * @author Rafael Steil
 * @version $Id: PostRepository.java,v 1.13 2006/08/23 02:13:48 rafaelsteil Exp $
 */
public class PostRepository implements Cacheable
{
	private static final int CACHE_SIZE = SystemGlobals.getIntValue(ConfigKeys.POSTS_CACHE_SIZE);
	private static final String FQN = "posts";
	private static CacheEngine cache;
	
	/**
	 * @see net.jforum.cache.Cacheable#setCacheEngine(net.jforum.cache.CacheEngine)
	 */
	public void setCacheEngine(CacheEngine engine)
	{
		cache = engine;
	}
	
	public static int size()
	{
		Map m = (Map)cache.get(FQN);
		return (m != null ? m.size() : 0);
	}
	
	public static int size(int topicId)
	{
		List posts = (List)cache.get(FQN, Integer.toString(topicId));
		return (posts == null ? 0 : posts.size());
	}
	
	public static Collection cachedTopics()
	{
		Map m = (Map)cache.get(FQN);
		if (m == null) {
			return new ArrayList();
		}
		
		return m.keySet();
	}
		
	public static List selectAllByTopicByLimit(int topicId, int start, int count)  
	{
		String tid = Integer.toString(topicId);
		
		List posts = (List)cache.get(FQN, tid);
		if (posts == null || posts.size() == 0) {
			PostDAO pm = DataAccessDriver.getInstance().newPostDAO();
			posts = pm.selectAllByTopic(topicId);
			
			for (Iterator iter = posts.iterator(); iter.hasNext(); ) {
				PostCommon.preparePostForDisplay((Post)iter.next());
			}
	
			Map topics = (Map)cache.get(FQN);
			if (topics == null || topics.size() == 0 || topics.size() < CACHE_SIZE) {
				cache.add(FQN, tid, posts);
			}
			else {
				if (!(topics instanceof LinkedHashMap)) {
					topics = new LinkedHashMap(topics) {
						protected boolean removeEldestEntry(java.util.Map.Entry eldest) {
							return this.size() > CACHE_SIZE;
						}
					};
				}
				
				topics.put(tid, posts);
				cache.add(FQN, topics);
			}
		}
		
		int size = posts.size();
		return posts.subList(start, (size < start + count) ? size : start + count);
   }
	
	public static void remove(int topicId, int postId)
	{
		synchronized (FQN) {
			String tid = Integer.toString(topicId);
			
			List posts = (List)cache.get(FQN, tid);
			
			if (posts != null) {
				Post p = new Post();
				p.setId(postId);
				posts.remove(p);
				
				cache.add(FQN, tid, posts);
			}
		}
	}
	
	public static void update(int topicId, Post p)
	{
		String tid = Integer.toString(topicId);
		List posts = (List)cache.get(FQN, tid);
		if (posts != null && posts.contains(p)) {
			posts.set(posts.indexOf(p), p);
			cache.add(FQN, tid, posts);
		}
	}
	
	public static void append(int topicId, Post p)
	{
		String tid = Integer.toString(topicId);
		List posts = (List)cache.get(FQN, tid);
		if (posts != null && !posts.contains(p)) {
			posts.add(p);
			cache.add(FQN, tid, posts);
		}
	}
	
	public static void clearCache(int topicId)
	{
		cache.remove(FQN, Integer.toString(topicId));
	}
}