/*
    * 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 org.apache.myfaces.util.AbstractAttributeMap;
  
  
  /**
   * HttpServletRequest headers as Map.
   * 
   * @author Anton Koinov (latest modification by $Author$)
   * @version $Revision$ $Date$
   */
  public final class RequestHeaderMap extends AbstractAttributeMap<String>
  {
      private final HttpServletRequest _httpServletRequest;
  
      RequestHeaderMap(final HttpServletRequest httpServletRequest)
      {
          _httpServletRequest = httpServletRequest;
      }
  
      @Override
      protected String getAttribute(final String key)
      {
          return _httpServletRequest.getHeader(key);
      }
  
      @Override
      protected void setAttribute(final String key, final String value)
      {
          throw new UnsupportedOperationException(
              "Cannot set HttpServletRequest Header");
      }
  
      @Override
      protected void removeAttribute(final String key)
      {
          throw new UnsupportedOperationException(
              "Cannot remove HttpServletRequest Header");
      }
  
      @Override
      @SuppressWarnings("unchecked")
      protected Enumeration<String> getAttributeNames()
      {
          return _httpServletRequest.getHeaderNames();
      }
  
      @Override
      public void putAll(final Map<? extends String, ? extends String> t)
      {
          throw new UnsupportedOperationException();
      }
  
  
      @Override
      public void clear()
      {
          throw new UnsupportedOperationException();
      }    
  }