Java tutorial
/* * 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://socialsite.dev.java.net/legal/CDDL+GPL.html * or 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 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 com.sun.socialsite.web.listeners; import com.sun.socialsite.config.Config; import java.util.ArrayList; import java.util.Collection; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; import java.util.concurrent.ConcurrentLinkedQueue; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; import javax.servlet.http.HttpSession; import javax.servlet.http.HttpSessionActivationListener; import javax.servlet.http.HttpSessionEvent; import javax.servlet.http.HttpSessionListener; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; /** * SessionListener */ public class SessionListener implements HttpSessionActivationListener, HttpSessionListener, ServletContextListener { private static final long serialVersionUID = 0L; private static Log log = LogFactory.getLog(SessionListener.class); private static Map<String, HttpSession> activeSessions = new ConcurrentHashMap<String, HttpSession>(); private static ConcurrentHashMap<HttpSession, Collection<Object>> listenersMap = new ConcurrentHashMap<HttpSession, Collection<Object>>(); private static Integer sessionTimeout = null; public static void addListener(HttpSession session, Object listener) { Collection<Object> listenersForSession = listenersMap.get(session); if (listenersForSession == null) { listenersMap.putIfAbsent(session, new ConcurrentLinkedQueue<Object>()); listenersForSession = listenersMap.get(session); } listenersForSession.add(listener); log.debug(String.format("addListener(%s, %s): listenersForSession.size=%d", session, listener, listenersForSession.size())); } /** * Returns all listeners which have registered to receive events * for the specified HttpSession. * @param session the HttpSession for which listeners are sought. */ private static Collection<Object> getListeners(HttpSession session) { Collection<Object> results = new ArrayList<Object>(); Collection<Object> listenersForSession = listenersMap.get(session); if (listenersForSession != null) { results.addAll(listenersForSession); } log.debug(String.format("getListeners(%s): results.size=%d", session, results.size())); return results; } public static HttpSession getSession(String sessionId) { return activeSessions.get(sessionId); } public void contextInitialized(ServletContextEvent event) { activeSessions.clear(); sessionTimeout = Config.getIntProperty("socialsite.http.session.timeout"); if (sessionTimeout != 0) { log.info(String.format("HttpSession timeout is %d seconds", sessionTimeout)); } else { sessionTimeout = null; } } public void contextDestroyed(ServletContextEvent event) { activeSessions.clear(); } public void sessionCreated(HttpSessionEvent se) { log.debug(String.format("sessionCreated(%s)", se.getSession().getId())); activeSessions.put(se.getSession().getId(), se.getSession()); if (sessionTimeout != null) { se.getSession().setMaxInactiveInterval(sessionTimeout); } for (Object listener : getListeners(se.getSession())) { if (listener instanceof HttpSessionListener) { ((HttpSessionListener) listener).sessionCreated(se); } } } public void sessionDestroyed(HttpSessionEvent se) { log.debug(String.format("sessionDestroyed(%s)", se.getSession().getId())); activeSessions.remove(se.getSession().getId()); for (Object listener : getListeners(se.getSession())) { if (listener instanceof HttpSessionListener) { ((HttpSessionListener) listener).sessionDestroyed(se); } } } public void sessionDidActivate(HttpSessionEvent se) { log.debug(String.format("sessionDidActivate(%s)", se.getSession().getId())); activeSessions.put(se.getSession().getId(), se.getSession()); for (Object listener : getListeners(se.getSession())) { if (listener instanceof HttpSessionActivationListener) { ((HttpSessionActivationListener) listener).sessionDidActivate(se); } } } public void sessionWillPassivate(HttpSessionEvent se) { log.debug(String.format("sessionWillPassivate(%s)", se.getSession().getId())); activeSessions.remove(se.getSession().getId()); for (Object listener : getListeners(se.getSession())) { if (listener instanceof HttpSessionActivationListener) { ((HttpSessionActivationListener) listener).sessionWillPassivate(se); } } } }