/*
    * 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.Collections;
  import java.util.Enumeration;
  import java.util.Map;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpSession;
  
  import org.apache.myfaces.util.AbstractThreadSafeAttributeMap;
  
  
  /**
   * HttpSession attibutes as Map.
   *
   * @author Anton Koinov (latest modification by $Author$)
   * @version $Revision$ $Date$
   */
  public final class SessionMap extends AbstractThreadSafeAttributeMap<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) ? Collections.emptyEnumeration() : httpSession.getAttributeNames();
      }
  
      @Override
      public void putAll(final Map<? extends String, ? extends Object> t)
      {
          throw new UnsupportedOperationException();
      }
      
      // we can use public void clear() from super-class
      
      private HttpSession _getSession()
      {
          return _httpRequest.getSession(false);
      }
  
  }