    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}