    001package org.apache.turbine.services.session;
    002
    003
    004/*
    005 * Licensed to the Apache Software Foundation (ASF) under one
    006 * or more contributor license agreements.  See the NOTICE file
    007 * distributed with this work for additional information
    008 * regarding copyright ownership.  The ASF licenses this file
    009 * to you under the Apache License, Version 2.0 (the
    010 * "License"); you may not use this file except in compliance
    011 * with the License.  You may obtain a copy of the License at
    012 *
    013 *   http://www.apache.org/licenses/LICENSE-2.0
    014 *
    015 * Unless required by applicable law or agreed to in writing,
    016 * software distributed under the License is distributed on an
    017 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    018 * KIND, either express or implied.  See the License for the
    019 * specific language governing permissions and limitations
    020 * under the License.
    021 */
    022
    023
    024import java.io.Serializable;
    025
    026import javax.servlet.http.HttpSessionActivationListener;
    027import javax.servlet.http.HttpSessionEvent;
    028import javax.servlet.http.HttpSessionListener;
    029
    030import org.apache.turbine.services.TurbineServices;
    031
    032/**
    033 * This class is a listener for both session creation and destruction,
    034 * and for session activation and passivation.  It must be configured
    035 * via your web application's <code>web.xml</code> deployment
    036 * descriptor as follows for the container to call it:
    037 *
    038 * <pre>
    039 * &lt;listener&gt;
    040 *   &lt;listener-class&gt;
    041 *     org.apache.turbine.session.SessionListener
    042 *   &lt;/listener-class&gt;
    043 * &lt;/listener&gt;
    044 * </pre>
    045 *
    046 * <code>&lt;listener&gt;</code> elements can occur between
    047 * <code>&lt;context-param&gt;</code> and <code>&lt;servlet&gt;</code>
    048 * elements in your deployment descriptor.
    049 *
    050 * The {@link #sessionCreated(HttpSessionEvent)} callback will
    051 * automatically add an instance of this listener to any newly created
    052 * <code>HttpSession</code> for detection of session passivation and
    053 * re-activation.
    054 *
    055 * @since 2.3
    056 * @version $Id: SessionListener.java 1773378 2016-12-09 13:19:59Z tv $
    057 * @author <a href="mailto:quintonm@bellsouth.net">Quinton McCombs</a>
    058 * @author <a href="mailto:dlr@apache.org">Daniel Rall</a>
    059 * @see javax.servlet.http.HttpSessionListener
    060 */
    061public class SessionListener
    062        implements HttpSessionListener, HttpSessionActivationListener, Serializable
    063{
    064    // ---- HttpSessionListener implementation -----------------------------
    065
    066    /**
    067     * Serial version.
    068     */
    069    private static final long serialVersionUID = -8083730704842809870L;
    070
    071    /**
    072     * The session service.
    073     */
    074    private SessionService sessionService;
    075
    076    /**
    077     * Lazy initialization
    078     *
    079     * @return the sessionService
    080     */
    081    private SessionService getSessionService()
    082    {
    083        // don't care about synchronization, lookup is cheap
    084        if (sessionService == null)
    085        {
    086            sessionService = (SessionService)TurbineServices.getInstance().getService(SessionService.SERVICE_NAME);
    087        }
    088
    089        return sessionService;
    090    }
    091
    092    /**
    093     * Called by the servlet container when a new session is created
    094     *
    095     * @param event Session creation event.
    096     */
    097    @Override
    098    public void sessionCreated(HttpSessionEvent event)
    099    {
    100        getSessionService().addSession(event.getSession());
    101        event.getSession().setAttribute(getClass().getName(), this);
    102    }
    103
    104    /**
    105     * Called by the servlet container when a session is destroyed
    106     *
    107     * @param event Session destruction event.
    108     */
    109    @Override
    110    public void sessionDestroyed(HttpSessionEvent event)
    111    {
    112        getSessionService().removeSession(event.getSession());
    113    }
    114
    115
    116    // ---- HttpSessionActivationListener implementation -------------------
    117
    118    /**
    119     * Called by the servlet container when an existing session is
    120     * (re-)activated.
    121     *
    122     * @param event Session activation event.
    123     */
    124    @Override
    125    public void sessionDidActivate(HttpSessionEvent event)
    126    {
    127        getSessionService().addSession(event.getSession());
    128    }
    129
    130    /**
    131     * Called by the servlet container when a an existing session is
    132     * passivated.
    133     *
    134     * @param event Session passivation event.
    135     */
    136    @Override
    137    public void sessionWillPassivate(HttpSessionEvent event)
    138    {
    139        getSessionService().removeSession(event.getSession());
    140    }
    141}