/*
    * 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.ArrayList;
  import java.util.Enumeration;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import javax.servlet.http.HttpServletRequest;
  
  import org.apache.myfaces.util.AbstractAttributeMap;
  
  
  /**
   * HttpServletRequest header values (multi-value headers) as Map of String[].
   * 
   * @author Anton Koinov (latest modification by $Author: lu4242 $)
   * @version $Revision: 1000660 $ $Date: 2010-09-23 18:02:43 -0500 (Thu, 23 Sep 2010) $
   */
  public class RequestHeaderValuesMap extends AbstractAttributeMap
  {
      private final HttpServletRequest _httpServletRequest;
      private final Map                _valueCache = new HashMap();
  
      RequestHeaderValuesMap(HttpServletRequest httpServletRequest)
      {
          _httpServletRequest = httpServletRequest;
      }
  
      protected Object getAttribute(String key)
      {
          Object ret = _valueCache.get(key);
          if (ret == null)
          {
              _valueCache.put(key, ret = toArray(_httpServletRequest
                  .getHeaders(key)));
          }
  
          return ret;
      }
  
      protected void setAttribute(String key, Object value)
      {
          throw new UnsupportedOperationException(
              "Cannot set HttpServletRequest HeaderValues");
      }
  
      protected void removeAttribute(String key)
      {
          throw new UnsupportedOperationException(
              "Cannot remove HttpServletRequest HeaderValues");
      }
  
      protected Enumeration getAttributeNames()
      {
          return _httpServletRequest.getHeaderNames();
      }
  
      private String[] toArray(Enumeration e)
      {
          List ret = new ArrayList();
  
          while (e.hasMoreElements())
          {
              ret.add(e.nextElement());
          }
  
          return (String[]) ret.toArray(new String[ret.size()]);
      }
  }