/*

  * 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 $Author$)

  * @version $Revision$ $Date$

  */

 public final class RequestHeaderValuesMap extends AbstractAttributeMap<String[]>

 {

     private final HttpServletRequest _httpServletRequest;

     private final Map<String, String[]> _valueCache = new HashMap<String, String[]>();

     RequestHeaderValuesMap(final HttpServletRequest httpServletRequest)

     {

         _httpServletRequest = httpServletRequest;

     }

     @Override

     @SuppressWarnings("unchecked")

     protected String[] getAttribute(final String key)

     {

         String[] ret = _valueCache.get(key);

         if (ret == null)

         {

             ret = toArray(_httpServletRequest.getHeaders(key));

             _valueCache.put(key, ret);

         }

         return ret;

     }

     @Override

     protected void setAttribute(final String key, final String[] value)

     {

         throw new UnsupportedOperationException("Cannot set HttpServletRequest HeaderValues");

     }

     @Override

     protected void removeAttribute(final String key)

     {

         throw new UnsupportedOperationException("Cannot remove HttpServletRequest HeaderValues");

     }

     @Override

     @SuppressWarnings("unchecked")

     protected Enumeration<String> getAttributeNames()

     {

         return _httpServletRequest.getHeaderNames();

     }

     private String[] toArray(Enumeration<String> e)

     {

         List<String> ret = new ArrayList<String>();

         while (e.hasMoreElements())

         {

             ret.add(e.nextElement());

         }

         return ret.toArray(new String[ret.size()]);

     }

 }