/*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you under the Apache License, Version 2.0 (the

  * "License"); you may not use this file except in compliance

  * with the License.  You may obtain a copy of the License at

  *

  *   http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing,

  * software distributed under the License is distributed on an

  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

  * KIND, either express or implied.  See the License for the

  * specific language governing permissions and limitations

  * under the License.

  */

 package org.apache.myfaces.context.servlet;

 import java.util.Enumeration;

 import java.util.Map;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpSession;

 import org.apache.myfaces.shared_impl.util.NullEnumeration;

 import org.apache.myfaces.util.AbstractAttributeMap;

 /**

  * HttpSession attibutes as Map.

  *

  * @author Anton Koinov (latest modification by $Author: bommel $)

  * @version $Revision: 693059 $ $Date: 2008-09-08 06:42:28 -0500 (Mon, 08 Sep 2008) $

  */

 public final class SessionMap extends AbstractAttributeMap<Object>

 {

     private final HttpServletRequest _httpRequest;

     SessionMap(final HttpServletRequest httpRequest)

     {

         _httpRequest = httpRequest;

     }

     @Override

     protected Object getAttribute(final String key)

     {

         final HttpSession httpSession = getSession();

         return (httpSession == null) ? null : httpSession.getAttribute(key);

     }

     @Override

     protected void setAttribute(final String key, final Object value)

     {

         _httpRequest.getSession(true).setAttribute(key, value);

     }

     @Override

     protected void removeAttribute(final String key)

     {

         final HttpSession httpSession = getSession();

         if (httpSession != null)

         {

             httpSession.removeAttribute(key);

         }

     }

     @Override

     @SuppressWarnings("unchecked")

     protected Enumeration<String> getAttributeNames()

     {

         final HttpSession httpSession = getSession();

         return (httpSession == null) ? NullEnumeration.instance() : httpSession.getAttributeNames();

     }

     private HttpSession getSession()

     {

         return _httpRequest.getSession(false);

     }

     @Override

     public void putAll(final Map t)

     {

         throw new UnsupportedOperationException();

     }

     /**

      * This will clear the session without invalidation. If no session has been created, it will simply return.

      */

     @Override

     public void clear()

     {

         final HttpSession session = getSession();

         if (session == null)

             return;

         for (final Enumeration attributeNames = session.getAttributeNames(); attributeNames.hasMoreElements();)

         {

             final String attributeName = (String) attributeNames.nextElement();

             session.removeAttribute(attributeName);

         }

     }

 }