/*
    * $Id: SessionScopeExtractor.java 1066790 2011-02-03 12:06:20Z 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.request.jsp.extractor;
  
  import java.util.Enumeration;
  
  import javax.servlet.jsp.PageContext;
  
  import org.apache.tiles.request.attribute.AttributeExtractor;
  
  /**
   * Extracts attributes from session scope from {@link PageContext}.
   *
   * @version $Rev: 1066790 $ $Date: 2011-02-03 23:06:20 +1100 (Thu, 03 Feb 2011) $
   */
  public class SessionScopeExtractor implements AttributeExtractor {
  
      /**
       * The page context.
       */
      private PageContext context;
  
      /**
       * Constructor.
       *
       * @param context The page context.
       */
      public SessionScopeExtractor(PageContext context) {
          this.context = context;
      }
  
      @Override
      public void removeValue(String name) {
          if (context.getSession() == null) {
              return;
          }
          context.removeAttribute(name, PageContext.SESSION_SCOPE);
      }
  
      @Override
      public Enumeration<String> getKeys() {
          if (context.getSession() == null) {
              return null;
          }
          return context.getAttributeNamesInScope(PageContext.SESSION_SCOPE);
      }
  
      @Override
      public Object getValue(String key) {
          if (context.getSession() == null) {
              return null;
          }
          return context.getAttribute(key, PageContext.SESSION_SCOPE);
      }
  
      @Override
      public void setValue(String key, Object value) {
          if (context.getSession() == null) {
              return;
          }
          context.setAttribute(key, value, PageContext.SESSION_SCOPE);
      }
  }