jforum example source code file (TopicRepository.java)

This example jforum source code file (TopicRepository.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, fqn, fqn_forum, integer, linkedlist, linkedlist, list, list, map, recent, relation, relation, string, string, util

The jforum TopicRepository.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: 05/04/2004 - 20:11:44
 * The JForum Project
 * http://www.jforum.net
 */
package net.jforum.repository;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
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.TopicDAO;
import net.jforum.entities.Topic;
import net.jforum.entities.TopicTypeComparator;
import net.jforum.util.preferences.ConfigKeys;
import net.jforum.util.preferences.SystemGlobals;

/**
 * Repository for the last n topics for each forum.
 * 
 * @author Rafael Steil
 * @author James Yong
 * @version $Id: TopicRepository.java,v 1.33 2007/09/05 04:00:27 rafaelsteil Exp $
 */
public class TopicRepository implements Cacheable
{
	private static int maxItems = SystemGlobals.getIntValue(ConfigKeys.TOPICS_PER_PAGE);
	
	private static final String FQN = "topics";
	private static final String RECENT = "recent";
	private static final String HOTTEST = "hottest";
	private static final String FQN_FORUM = FQN + "/byforum";
	private static final String RELATION = "relation";
	private static final String FQN_LOADED = FQN + "/loaded";
	private static final Comparator TYPE_COMPARATOR = new TopicTypeComparator();
	
	private static CacheEngine cache;
	
	/**
	 * @see net.jforum.cache.Cacheable#setCacheEngine(net.jforum.cache.CacheEngine)
	 */
	public void setCacheEngine(CacheEngine engine)
	{
		cache = engine;
	}
	
	public static boolean isLoaded(int forumId)
	{
		return "1".equals(cache.get(FQN_LOADED, Integer.toString(forumId)));
	}

	/**
	 * Add topic to the FIFO stack
	 * 
	 * @param topic The topic to add to stack
	 */
	public synchronized static void pushTopic(Topic topic)
	{
		if (SystemGlobals.getBoolValue(ConfigKeys.TOPIC_CACHE_ENABLED)) {
			int limit = SystemGlobals.getIntValue(ConfigKeys.RECENT_TOPICS);
			
			LinkedList l = (LinkedList)cache.get(FQN, RECENT);
			if (l == null || l.size() == 0) {
				l = new LinkedList(loadMostRecentTopics());
			}
			
			l.remove(topic);
			l.addFirst(topic);
			
			while (l.size() > limit) {
				l.removeLast();
			}
			
			cache.add(FQN, RECENT, l);
		}
	}

	/**
	 * Get all cached recent topics. 
	 * 
	 */	
	public static List getRecentTopics()
	{
		List l = (List)cache.get(FQN, RECENT);
		
		if (l == null || l.size() == 0
			|| !SystemGlobals.getBoolValue(ConfigKeys.TOPIC_CACHE_ENABLED)) {
			l = loadMostRecentTopics();
		}
		
		return new ArrayList(l);
	}	

	/**
	 * Get all cached hottest topics.
	 *
	 */
	public static List getHottestTopics()
	{   
	    List l = (List)cache.get(FQN, HOTTEST);
	       
	    if (l == null || l.size() == 0
	        || !SystemGlobals.getBoolValue(ConfigKeys.TOPIC_CACHE_ENABLED)) {
	        l = loadHottestTopics();
	    }
	    
	    return new ArrayList(l);
	}
	
	/**
	 * Add recent topics to the cache
	 */
	public synchronized static List loadMostRecentTopics()
	{
		TopicDAO tm = DataAccessDriver.getInstance().newTopicDAO();
		int limit = SystemGlobals.getIntValue(ConfigKeys.RECENT_TOPICS);
		
		List l = tm.selectRecentTopics(limit);
		cache.add(FQN, RECENT, new LinkedList(l));
		
		return l;
	}

	/**
	 * Add hottest topics to the cache
	 */
	public synchronized static List loadHottestTopics()
	{
	    TopicDAO tm = DataAccessDriver.getInstance().newTopicDAO();
	    int limit = SystemGlobals.getIntValue(ConfigKeys.HOTTEST_TOPICS);
	    
	    List l = tm.selectHottestTopics(limit);
	    cache.add(FQN, HOTTEST, new LinkedList(l));
	    
	    return l;
	}
	
	/**
	 * Add topics to the cache
	 * 
	 * @param forumId The forum id to which the topics are related
	 * @param topics The topics to add
	 */
	public static void addAll(int forumId, List topics)
	{
		if (SystemGlobals.getBoolValue(ConfigKeys.TOPIC_CACHE_ENABLED)) {
			synchronized (FQN_FORUM) {
				cache.add(FQN_FORUM, Integer.toString(forumId), new LinkedList(topics));
				
				Map m = (Map)cache.get(FQN, RELATION);
				
				if (m == null) {
					m = new HashMap();
				}
				
				Integer fId = new Integer(forumId);
				
				for (Iterator iter = topics.iterator(); iter.hasNext(); ) {
					Topic t = (Topic)iter.next();
					
					m.put(new Integer(t.getId()), fId);
				}
				
				cache.add(FQN, RELATION, m);
				cache.add(FQN_LOADED, Integer.toString(forumId), "1");
			}
		}
	}
	
	/**
	 * Clears the cache
	 * 
	 * @param forumId The forum id to clear the cache
	 */
	public static void clearCache(int forumId) 
	{
		synchronized (FQN_FORUM) {
			cache.add(FQN_FORUM, Integer.toString(forumId), new LinkedList());
			cache.remove(FQN, RELATION);
		}
	}
	
	/**
	 * Adds a new topic to the cache
	 * 
	 * @param topic The topic to add
	 */
	public static void addTopic(Topic topic)
	{
		if (!SystemGlobals.getBoolValue(ConfigKeys.TOPIC_CACHE_ENABLED)) {
			return;
		}
		
		synchronized (FQN_FORUM) {
			String forumId = Integer.toString(topic.getForumId());
			LinkedList list = (LinkedList)cache.get(FQN_FORUM, forumId);
			
			if (list == null) {
				list = new LinkedList();
				list.add(topic);
			}
			else {
				boolean contains = list.contains(topic);
				
				// If the cache is full, remove the eldest element
				if (!contains && list.size() + 1 > maxItems) {
					list.removeLast();
				}
				else if (contains) {
					list.remove(topic);
				}
				
				list.add(topic);
				
				Collections.sort(list, TYPE_COMPARATOR);
			}
			
			cache.add(FQN_FORUM, forumId, list);
		
			Map m = (Map)cache.get(FQN, RELATION);
			
			if (m == null) {
				m = new HashMap();
			}
			
			m.put(new Integer(topic.getId()), new Integer(forumId));
			
			cache.add(FQN, RELATION, m);
		}
	}
	
	/**
	 * Updates a cached topic
	 * 
	 * @param topic The topic to update
	 */
	public static void updateTopic(Topic topic)
	{
		if (SystemGlobals.getBoolValue(ConfigKeys.TOPIC_CACHE_ENABLED)) {
			synchronized (FQN_FORUM) {
				String forumId = Integer.toString(topic.getForumId());
				List l = (List)cache.get(FQN_FORUM, forumId);
				
				if (l != null) {
					int index = l.indexOf(topic);
					
					if (index > -1) {
						l.set(index, topic);
						cache.add(FQN_FORUM, forumId, l);
					}
				}
			}
		}
	}
	
	/**
	 * Gets a cached topic.
	 * 
	 * @param t The topic to try to get from the cache. The instance
	 * passed as argument should have ae least the topicId and forumId set
	 * @return The topic instance, if found, or <code>null otherwise. 
	 */
	public static Topic getTopic(Topic t)
	{
		if (!SystemGlobals.getBoolValue(ConfigKeys.TOPIC_CACHE_ENABLED)) {
			return null;
		}
		
		if (t.getForumId() == 0) {
			Map m = (Map)cache.get(FQN, RELATION);
			
			if (m != null) {
				Integer forumId = (Integer)m.get(new Integer(t.getId()));
				
				if (forumId != null) {
					t.setForumId(forumId.intValue());
				}
			}
			
			if (t.getForumId() == 0) {
				return null;
			}
		}
		
		List l = (List)cache.get(FQN_FORUM, Integer.toString(t.getForumId()));
		
		int index = -1;
		
		if (l != null) {
			index = l.indexOf(t);
		}
		
		return (index == -1 ? null : (Topic)l.get(index));
	}
	
	/**
	 * Checks if a topic is cached
	 * 
	 * @param topic The topic to verify
	 * @return <code>true if the topic is cached, or false if not.
	 */
	public static boolean isTopicCached(Topic topic)
	{
		if (!SystemGlobals.getBoolValue(ConfigKeys.TOPIC_CACHE_ENABLED)) {
			return false;
		}
		
		String forumId = Integer.toString(topic.getForumId());
		List list = (List)cache.get(FQN_FORUM, forumId);
		
		return list == null ? false : list.contains(topic);
	}
	
	/**
	 * Get all cached topics related to a forum. 
	 * 
	 * @param forumid The forum id 
	 * @return <code>ArrayList with the topics.
	 */
	public static List getTopics(int forumid)
	{
		if (SystemGlobals.getBoolValue(ConfigKeys.TOPIC_CACHE_ENABLED)) {
			synchronized (FQN_FORUM) {
				List returnList = (List)cache.get(FQN_FORUM, Integer.toString(forumid));

				if (returnList == null) {
					return new ArrayList();
				}
				
				return new ArrayList(returnList);
			}
		}
		
		return new ArrayList();
	}
}