/*
    * 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.jxpath.servlet;
  
  import java.util.Enumeration;
  import java.util.HashSet;
  import javax.servlet.http.HttpSession;
  
  import org.apache.commons.jxpath.JXPathException;
  
  /**
   * Implementation of the {@link org.apache.commons.jxpath.DynamicPropertyHandler}
   * interface that provides access to attributes of a @{link HttpSession}.
   *
   * @author Dmitri Plotnikov
   * @version $Revision: 652845 $ $Date: 2008-05-02 19:46:46 +0200 (Fr, 02 Mai 2008) $
   */
  public class HttpSessionHandler extends ServletContextHandler {
  
      protected void collectPropertyNames(HashSet set, Object bean) {
          HttpSessionAndServletContext handle =
              (HttpSessionAndServletContext) bean;
          super.collectPropertyNames(set, handle.getServletContext());
          HttpSession session = handle.getSession();
          if (session != null) {
              Enumeration e = session.getAttributeNames();
              while (e.hasMoreElements()) {
                  set.add(e.nextElement());
              }
          }
      }
  
      public Object getProperty(Object bean, String property) {
          HttpSessionAndServletContext handle =
              (HttpSessionAndServletContext) bean;
          HttpSession session = handle.getSession();
          if (session != null) {
              Object object = session.getAttribute(property);
              if (object != null) {
                  return object;
              }
          }
          return super.getProperty(handle.getServletContext(), property);
      }
  
      public void setProperty(Object bean, String property, Object value) {
          HttpSessionAndServletContext handle =
              (HttpSessionAndServletContext) bean;
          HttpSession session = handle.getSession();
          if (session != null) {
              session.setAttribute(property, value);
          }
          else {
              throw new JXPathException("Cannot set session attribute: "
                      + "there is no session");
          }
      }
  }