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    }