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    1   package org.apache.turbine.services.session;
    2
    3
    4   /*
    5    * Licensed to the Apache Software Foundation (ASF) under one
    6    * or more contributor license agreements.  See the NOTICE file
    7    * distributed with this work for additional information
    8    * regarding copyright ownership.  The ASF licenses this file
    9    * to you under the Apache License, Version 2.0 (the
    10   * "License"); you may not use this file except in compliance
    11   * with the License.  You may obtain a copy of the License at
    12   *
    13   *   http://www.apache.org/licenses/LICENSE-2.0
    14   *
    15   * Unless required by applicable law or agreed to in writing,
    16   * software distributed under the License is distributed on an
    17   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    18   * KIND, either express or implied.  See the License for the
    19   * specific language governing permissions and limitations
    20   * under the License.
    21   */
    22
    23
    24  import java.io.Serializable;
    25
    26  import javax.servlet.http.HttpSessionActivationListener;
    27  import javax.servlet.http.HttpSessionEvent;
    28  import javax.servlet.http.HttpSessionListener;
    29
    30  import org.apache.turbine.services.TurbineServices;
    31
    32  /**
    33   * This class is a listener for both session creation and destruction,
    34   * and for session activation and passivation.  It must be configured
    35   * via your web application's <code>web.xml</code> deployment
    36   * descriptor as follows for the container to call it:
    37   *
    38   * <pre>
    39   * &lt;listener&gt;
    40   *   &lt;listener-class&gt;
    41   *     org.apache.turbine.session.SessionListener
    42   *   &lt;/listener-class&gt;
    43   * &lt;/listener&gt;
    44   * </pre>
    45   *
    46   * <code>&lt;listener&gt;</code> elements can occur between
    47   * <code>&lt;context-param&gt;</code> and <code>&lt;servlet&gt;</code>
    48   * elements in your deployment descriptor.
    49   *
    50   * The {@link #sessionCreated(HttpSessionEvent)} callback will
    51   * automatically add an instance of this listener to any newly created
    52   * <code>HttpSession</code> for detection of session passivation and
    53   * re-activation.
    54   *
    55   * @since 2.3
    56   * @version $Id: SessionListener.java 1773378 2016-12-09 13:19:59Z tv $
    57   * @author <a href="mailto:quintonm@bellsouth.net">Quinton McCombs</a>
    58   * @author <a href="mailto:dlr@apache.org">Daniel Rall</a>
    59   * @see javax.servlet.http.HttpSessionListener
    60   */
    61  public class SessionListener
    62          implements HttpSessionListener, HttpSessionActivationListener, Serializable
    63  {
    64      // ---- HttpSessionListener implementation -----------------------------
    65
    66      /**
    67       * Serial version.
    68       */
    69      private static final long serialVersionUID = -8083730704842809870L;
    70
    71      /**
    72       * The session service.
    73       */
    74      private SessionService sessionService;
    75
    76      /**
    77       * Lazy initialization
    78       *
    79       * @return the sessionService
    80       */
    81      private SessionService getSessionService()
    82      {
    83          // don't care about synchronization, lookup is cheap
    84          if (sessionService == null)
    85          {
    86              sessionService = (SessionService)TurbineServices.getInstance().getService(SessionService.SERVICE_NAME);
    87          }
    88
    89          return sessionService;
    90      }
    91
    92      /**
    93       * Called by the servlet container when a new session is created
    94       *
    95       * @param event Session creation event.
    96       */
    97      @Override
    98      public void sessionCreated(HttpSessionEvent event)
    99      {
    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 }