/*
    * $Id: ServletRequestScopeMap.java 581987 2007-10-04 19:03:29Z apetrelli $
    *
    * 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.ServletRequest;
  
  import org.apache.tiles.context.MapEntry;
  
  /***
   * <p>Private implementation of <code>Map</code> for servlet request
   * attributes.</p>
   *
   * @version $Rev: 581987 $ $Date: 2007-10-04 21:03:29 +0200 (Thu, 04 Oct 2007) $
   */
  
  final class ServletRequestScopeMap implements Map<String, Object> {
  
  
      /***
       * Constructor.
       *
       * @param request The request object to use.
       */
      public ServletRequestScopeMap(ServletRequest request) {
          this.request = request;
      }
  
  
      /***
       * The request object to use.
       */
      private ServletRequest request = null;
  
  
      /*** {@inheritDoc} */
      public void clear() {
          Iterator<String> keys = keySet().iterator();
          while (keys.hasNext()) {
              request.removeAttribute(keys.next());
          }
      }
  
  
      /*** {@inheritDoc} */
      public boolean containsKey(Object key) {
          return (request.getAttribute(key(key)) != null);
      }
  
  
      /*** {@inheritDoc} */
      @SuppressWarnings("unchecked")
      public boolean containsValue(Object value) {
          if (value == null) {
              return (false);
          }
          Enumeration<String> keys = request.getAttributeNames();
          while (keys.hasMoreElements()) {
              Object next = request.getAttribute(keys.nextElement());
              if (next == value) {
                  return (true);
              }
          }
          return (false);
      }
  
  
      /*** {@inheritDoc} */
      @SuppressWarnings("unchecked")
      public Set<Map.Entry<String, Object>> entrySet() {
          Set<Map.Entry<String, Object>> set = new HashSet<Map.Entry<String, Object>>();
          Enumeration<String> keys = request.getAttributeNames();
          String key;
         while (keys.hasMoreElements()) {
             key = keys.nextElement();
             set.add(new MapEntry<String, Object>(key,
                     request.getAttribute(key), true));
         }
         return (set);
     }
 
 
     /*** {@inheritDoc} */
     @SuppressWarnings("unchecked")
     public boolean equals(Object o) {
         ServletRequest otherRequest = ((ServletRequestScopeMap) o).request;
         boolean retValue = true;
         synchronized (request) {
             for (Enumeration<String> attribs = request.getAttributeNames(); attribs
                     .hasMoreElements()
                     && retValue;) {
                 String attributeName = attribs.nextElement();
                 retValue = request.getAttribute(attributeName).equals(
                         otherRequest.getAttribute(attributeName));
             }
         }
 
         return retValue;
     }
 
 
     /*** {@inheritDoc} */
     public Object get(Object key) {
         return (request.getAttribute(key(key)));
     }
 
 
     /*** {@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.getAttributeNames();
         while (keys.hasMoreElements()) {
             set.add(keys.nextElement());
         }
         return (set);
     }
 
 
     /*** {@inheritDoc} */
     public Object put(String key, Object value) {
         if (value == null) {
             return (remove(key));
         }
         String skey = key(key);
         Object previous = request.getAttribute(skey);
         request.setAttribute(skey, value);
         return (previous);
     }
 
 
     /*** {@inheritDoc} */
     public void putAll(Map<? extends String, ? extends Object> map) {
         Iterator<? extends String> keys = map.keySet().iterator();
         while (keys.hasNext()) {
             String key = keys.next();
             request.setAttribute(key, map.get(key));
         }
     }
 
 
     /*** {@inheritDoc} */
     public Object remove(Object key) {
         String skey = key(key);
         Object previous = request.getAttribute(skey);
         request.removeAttribute(skey);
         return (previous);
     }
 
 
     /*** {@inheritDoc} */
     @SuppressWarnings("unchecked")
     public int size() {
         int n = 0;
         Enumeration<String> keys = request.getAttributeNames();
         while (keys.hasMoreElements()) {
             keys.nextElement();
             n++;
         }
         return (n);
     }
 
 
     /*** {@inheritDoc} */
     @SuppressWarnings("unchecked")
     public Collection<Object> values() {
         List<Object> list = new ArrayList<Object>();
         Enumeration<String> keys = request.getAttributeNames();
         while (keys.hasMoreElements()) {
             list.add(request.getAttribute(keys.nextElement()));
         }
         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());
         }
     }
 
 
 }