/*
    * 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.commons.chain.web.servlet;
  
  
  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.HttpSession;
  import javax.servlet.http.HttpServletRequest;
  import org.apache.commons.chain.web.MapEntry;
  
  
  /**
   * <p>Private implementation of <code>Map</code> for HTTP session
   * attributes.</p>
   *
   * @author Craig R. McClanahan
   * @version $Revision: 661007 $ $Date: 2008-05-28 17:28:49 +0100 (Wed, 28 May 2008) $
   */
  
  final class ServletSessionScopeMap implements Map {
  
  
      public ServletSessionScopeMap(HttpServletRequest request) {
          this.request = request;
          sessionExists();
      }
  
  
      private HttpSession session = null;
      private HttpServletRequest request = null;
  
  
      public void clear() {
          if (sessionExists()) {
              Iterator keys = keySet().iterator();
              while (keys.hasNext()) {
                  session.removeAttribute((String) keys.next());
              }
          }
      }
  
  
      public boolean containsKey(Object key) {
          if (sessionExists()) {
              return (session.getAttribute(key(key)) != null);
          } else {
              return false;
          }
      }
  
  
      public boolean containsValue(Object value) {
          if (value == null || !sessionExists()) {
              return (false);
          }
          Enumeration keys = session.getAttributeNames();
          while (keys.hasMoreElements()) {
              Object next = session.getAttribute((String) keys.nextElement());
              if (value.equals(next)) {
                  return (true);
              }
          }
          return (false);
      }
  
  
      public Set entrySet() {
          Set set = new HashSet();
          if (sessionExists()) {
              Enumeration keys = session.getAttributeNames();
              String key;
              while (keys.hasMoreElements()) {
                  key = (String) keys.nextElement();
                  set.add(new MapEntry(key, session.getAttribute(key), true));
              }
          }
          return (set);
      }
 
 
     public boolean equals(Object o) {
         if (sessionExists()) {
             return (session.equals(o));
         } else {
             return false;
         }
     }
 
 
     public Object get(Object key) {
         if (sessionExists()) {
             return (session.getAttribute(key(key)));
         } else {
             return null;
         }
     }
 
 
     public int hashCode() {
         if (sessionExists()) {
             return (session.hashCode());
         } else {
             return 0;
         }
     }
 
 
     public boolean isEmpty() {
         if (sessionExists() &&
             session.getAttributeNames().hasMoreElements()) {
             return false;
         } else {
             return true;
         }
     }
 
 
     public Set keySet() {
         Set set = new HashSet();
         if (sessionExists()) {
             Enumeration keys = session.getAttributeNames();
             while (keys.hasMoreElements()) {
                 set.add(keys.nextElement());
             }
         }
         return (set);
     }
 
 
     public Object put(Object key, Object value) {
         if (value == null) {
             return (remove(key));
         }
 
         // Ensure the Session is created, if it
         // doesn't exist
         if (session == null) {
             session = request.getSession();
             request = null;
         }
 
         String skey = key(key);
         Object previous = session.getAttribute(skey);
         session.setAttribute(skey, value);
         return (previous);
     }
 
 
     public void putAll(Map map) {
         Iterator entries = map.entrySet().iterator();
         while (entries.hasNext()) {
             Map.Entry entry = (Map.Entry)entries.next();
             put(entry.getKey(), entry.getValue());
         }
     }
 
 
     public Object remove(Object key) {
         if (sessionExists()) {
             String skey = key(key);
             Object previous = session.getAttribute(skey);
             session.removeAttribute(skey);
             return (previous);
         } else {
             return (null);
         }
     }
 
 
     public int size() {
         int n = 0;
         if (sessionExists()) {
             Enumeration keys = session.getAttributeNames();
             while (keys.hasMoreElements()) {
                 keys.nextElement();
                 n++;
             }
         }
         return (n);
     }
 
 
     public Collection values() {
         List list = new ArrayList();
         if (sessionExists()) {
             Enumeration keys = session.getAttributeNames();
             while (keys.hasMoreElements()) {
                 list.add(session.getAttribute((String) keys.nextElement()));
             }
         }
         return (list);
     }
 
 
     private String key(Object key) {
         if (key == null) {
             throw new IllegalArgumentException();
         } else if (key instanceof String) {
             return ((String) key);
         } else {
             return (key.toString());
         }
     }
 
     private boolean sessionExists() {
         if (session == null) {
             session = request.getSession(false);
             if (session != null) {
                 request = null;
             }
         }
         if (session != null) {
             return true;
         } else {
             return false;
         }
     }
 
 }