001package org.apache.turbine.modules.actions.sessionvalidator;
002
003/*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements.  See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership.  The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License.  You may obtain a copy of the License at
011 *
012 *   http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied.  See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022import org.apache.turbine.modules.Action;
023
024/**
025 * The SessionValidator attempts to retrieve the User object from the
026 * Servlet API session that is associated with the request.  If the
027 * data cannot be retrieved, it is handled here.  If the user has not
028 * been marked as being logged into the system, the user is rejected
029 * and the screen is set to the screen.homepage value in
030 * TurbineResources.properties.
031 *
032 * <p>
033 *
034 * Other systems generally have a database table which stores this
035 * information, but we take advantage of the Servlet API here to save
036 * a hit to the database for each and every connection that a user
037 * makes.
038 *
039 * <p>
040 *
041 * This action is special in that it should only be executed by the
042 * Turbine servlet.
043 *
044 * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
045 * @version $Id: SessionValidator.java 1078552 2011-03-06 19:58:46Z tv $
046 */
047public abstract class SessionValidator extends Action
048{
049    // empty
050}