/*
    * $Id: SessionScopeExtractor.java 1199216 2011-11-08 12:25:24Z mck $
    *
    * 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.request.servlet.extractor;
  
  import java.util.Enumeration;
  import java.util.Collections;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpSession;
  
  import org.apache.tiles.request.attribute.AttributeExtractor;
  
  /**
   * Extract attributes from session scope.
   *
   * @version $Rev: 1199216 $ $Date: 2011-11-08 23:25:24 +1100 (Tue, 08 Nov 2011) $
   */
  public class SessionScopeExtractor implements AttributeExtractor {
  
      /**
       * The servlet request.
       */
      private HttpServletRequest request;
  
      /**
       * Constructor.
       *
       * @param request The servlet request.
       */
      public SessionScopeExtractor(HttpServletRequest request) {
          this.request = request;
      }
  
      @Override
      public void setValue(String name, Object value) {
          request.getSession().setAttribute(name, value);
      }
  
      @Override
      public void removeValue(String name) {
          HttpSession session = request.getSession(false);
          if (session != null) {
              session.removeAttribute(name);
          }
      }
  
      @SuppressWarnings("unchecked")
      @Override
      public Enumeration<String> getKeys() {
          HttpSession session = request.getSession(false);
          if (session != null) {
              return session.getAttributeNames();
          }
          return Collections.enumeration(Collections.<String>emptySet());
      }
  
      @Override
      public Object getValue(String key) {
          HttpSession session = request.getSession(false);
          if (session != null) {
              return session.getAttribute(key);
          }
          return null;
      }
  }