/*
    * $Id$
    *
    * 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.tiles.servlet.context;
  
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Enumeration;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  
  import javax.servlet.http.HttpServletRequest;
  
  import org.apache.tiles.context.MapEntry;
  
  
  /**
   * <p>Private implementation of <code>Map</code> for servlet request
   * name-values[].</p>
   *
   * @version $Rev$ $Date$
   */
  
  final class ServletHeaderValuesMap implements Map<String, String[]> {
  
  
      /**
       * Constructor.
       *
       * @param request The request object to use.
       */
      public ServletHeaderValuesMap(HttpServletRequest request) {
          this.request = request;
      }
  
  
      /**
       * The request object to use.
       */
      private HttpServletRequest request = null;
  
  
      /** {@inheritDoc} */
      public void clear() {
          throw new UnsupportedOperationException();
      }
  
  
      /** {@inheritDoc} */
      public boolean containsKey(Object key) {
          return (request.getHeader(key(key)) != null);
      }
  
  
      /** {@inheritDoc} */
      public boolean containsValue(Object value) {
          if (!(value instanceof String[])) {
              return (false);
          }
          String[] test = (String[]) value;
          Iterator<String[]> values = values().iterator();
          while (values.hasNext()) {
              String[] actual = values.next();
              if (test.length == actual.length) {
                  boolean matched = true;
                  for (int i = 0; i < test.length; i++) {
                      if (!test[i].equals(actual[i])) {
                          matched = false;
                          break;
                      }
                  }
                  if (matched) {
                      return (true);
                  }
              }
          }
          return (false);
      }
 
 
     /** {@inheritDoc} */
     @SuppressWarnings("unchecked")
     public Set<Map.Entry<String, String[]>> entrySet() {
         Set<Map.Entry<String, String[]>> set = new HashSet<Map.Entry<String, String[]>>();
         Enumeration<String> keys = request.getHeaderNames();
         String key;
         while (keys.hasMoreElements()) {
             key = keys.nextElement();
             Enumeration<String> headerEnum = request.getHeaders(key);
             set.add(new MapEntry<String, String[]>(key,
                     enumeration2array(headerEnum), false));
         }
         return (set);
     }
 
 
     /** {@inheritDoc} */
     @SuppressWarnings("unchecked")
     public boolean equals(Object o) {
         HttpServletRequest otherRequest = ((ServletHeaderValuesMap) o).request;
         boolean retValue = true;
         synchronized (request) {
             for (Enumeration<String> attribs = request.getHeaderNames(); attribs
                     .hasMoreElements()
                     && retValue;) {
                 String parameterName = attribs.nextElement();
                 retValue = request.getHeaders(parameterName).equals(
                         otherRequest.getHeaders(parameterName));
             }
         }
 
         return retValue;
     }
 
 
     /** {@inheritDoc} */
     @SuppressWarnings("unchecked")
     public String[] get(Object key) {
         List<String> list = new ArrayList<String>();
         Enumeration<String> values = request.getHeaders(key(key));
         while (values.hasMoreElements()) {
             list.add(values.nextElement());
         }
         return ((list.toArray(new String[list.size()])));
     }
 
 
     /** {@inheritDoc} */
     public int hashCode() {
         return (request.hashCode());
     }
 
 
     /** {@inheritDoc} */
     public boolean isEmpty() {
         return (size() < 1);
     }
 
 
     /** {@inheritDoc} */
     @SuppressWarnings("unchecked")
     public Set<String> keySet() {
         Set<String> set = new HashSet<String>();
         Enumeration<String> keys = request.getHeaderNames();
         while (keys.hasMoreElements()) {
             set.add(keys.nextElement());
         }
         return (set);
     }
 
 
     /** {@inheritDoc} */
     public String[] put(String key, String[] value) {
         throw new UnsupportedOperationException();
     }
 
 
     /** {@inheritDoc} */
     public void putAll(Map<? extends String, ? extends String[]> map) {
         throw new UnsupportedOperationException();
     }
 
 
     /** {@inheritDoc} */
     public String[] remove(Object key) {
         throw new UnsupportedOperationException();
     }
 
 
 
     /** {@inheritDoc} */
     @SuppressWarnings("unchecked")
     public int size() {
         int n = 0;
         Enumeration<String> keys = request.getHeaderNames();
         while (keys.hasMoreElements()) {
             keys.nextElement();
             n++;
         }
         return (n);
     }
 
 
     /** {@inheritDoc} */
     @SuppressWarnings("unchecked")
     public Collection<String[]> values() {
         List<String[]> list = new ArrayList<String[]>();
         Enumeration<String> keys = request.getHeaderNames();
         while (keys.hasMoreElements()) {
             String key = keys.nextElement();
             Enumeration<String> values = request.getHeaders(key);
             list.add(enumeration2array(values));
         }
         return (list);
     }
 
 
     /**
      * Returns the string representation of the key.
      *
      * @param key The key.
      * @return The string representation of the key.
      * @throws IllegalArgumentException If the key is <code>null</code>.
      */
     private String key(Object key) {
         if (key == null) {
             throw new IllegalArgumentException();
         } else if (key instanceof String) {
             return ((String) key);
         } else {
             return (key.toString());
         }
     }
 
     /**
      * Converts the content of a string enumeration to an array of strings.
      *
      * @param enumeration The enumeration to convert.
      * @return The corresponding array.
      */
     private String[] enumeration2array(Enumeration<String> enumeration) {
         List<String> list1 = new ArrayList<String>();
         while (enumeration.hasMoreElements()) {
             list1.add(enumeration.nextElement());
         }
 
         return list1.toArray(new String[list1.size()]);
     }
 }