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/*
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2007-2008 Sun Microsystems, Inc. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License. You can obtain
 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
 * or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
 * Sun designates this particular file as subject to the "Classpath" exception
 * as provided by Sun in the GPL Version 2 section of the License file that
 * accompanied this code.  If applicable, add the following below the License
 * Header, with the fields enclosed by brackets [] replaced by your own
 * identifying information: "Portions Copyrighted [year]
 * [name of copyright owner]"
 *
 * Contributor(s):
 *
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */
package org.atmosphere.cache;

import org.atmosphere.cpr.AtmosphereResource;
import org.atmosphere.cpr.AtmosphereResourceImpl;
import org.atmosphere.cpr.BroadcasterCache;
import org.atmosphere.util.LoggerUtils;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * Abstract {@link org.atmosphere.cpr.BroadcasterCache} which is used to implement headers or query parameters or
 * session based caching.
 *
 * @author Jeanfrancois Arcand
 */
public abstract class BroadcasterCacheBase implements BroadcasterCache {

    protected final static Logger logger = LoggerUtils.getLogger();

    protected final List queue = new CopyOnWriteArrayList();

    protected final ScheduledExecutorService reaper = Executors.newSingleThreadScheduledExecutor();

    protected int maxCachedinMs = 1000 * 5 * 60;

    public BroadcasterCacheBase() {
    }

    /**
     * {@inheritDoc}
     */
    public final void start() {
        reaper.scheduleAtFixedRate(new Runnable() {

            public void run() {
                Iterator i = queue.iterator();
                CachedMessage e;
                while (i.hasNext()) {
                    e = i.next();
                    if (logger.isLoggable(Level.FINE)) {
                        logger.fine("Message: " + e.message());
                    }

                    if (System.currentTimeMillis() - e.currentTime() > maxCachedinMs) {
                        if (logger.isLoggable(Level.FINE)) {
                            logger.fine("Pruning: " + e.message());
                        }
                        queue.remove(e);
                    } else {
                        break;
                    }
                }
            }
        }, 0, 60, TimeUnit.SECONDS);
    }

    /**
     * {@inheritDoc}
     */
    public final void stop() {
        reaper.shutdown();
    }

    /**
     * {@inheritDoc}
     */
    public final void addToCache(final AtmosphereResource r, final Object e) {

        if (logger.isLoggable(Level.FINE)) {
            logger.fine("Adding message for " + r + ": " + e);
        }

        CachedMessage cm = new CachedMessage(e, System.currentTimeMillis(), null);
        CachedMessage prev = null;
        if (!queue.isEmpty()) {
            prev = queue.get(queue.size() - 1);
        }

        if (prev != null) {
            prev.next(cm);
        }

        // Some indexing issue if this return true
        if (!queue.contains(cm)) {
            queue.add(cm);
        }

        if (prev == null) {
            cm = new CachedMessage(true);
        }

        if (r != null) {
            cache(r, cm);
        }
    }

    /**
     * Cache the last message broadcasted.
     *
     * @param r  {@link org.atmosphere.cpr.AtmosphereResource}.
     * @param cm {@link org.atmosphere.cache.BroadcasterCacheBase.CachedMessage}
     */
    abstract public void cache(final AtmosphereResource r, CachedMessage cm);

    /**
     * Return the last message broadcasted to the {@link org.atmosphere.cpr.AtmosphereResource}.
     *
     * @param r {@link org.atmosphere.cpr.AtmosphereResource}.
     * @return a {@link org.atmosphere.cache.BroadcasterCacheBase.CachedMessage}, or null if not matched.
     */
    abstract public CachedMessage retrieveLastMessage(final AtmosphereResource r);

    /**
     * {@inheritDoc}
     */
    public final List