    001    package 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
    022    import 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     */
    047    public abstract class SessionValidator extends Action
    048    {
    049        // empty
    050    }