simplecache.java

iiitAccessServer是一个用Java编写的基于规则的企业鉴别系统。它作为一个服务器工作

/*******************************************************************************
 * Copyright (C) 2002, 2003
 * ingenieurbuero fuer innovative informationstechnik (iiit)
 * Dipl.-Ing. Joerg Beckmann, Dortmund, Germany
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * version $Id: SimpleCache.java,v 1.10 2003/04/13 20:28:01 joerg Exp $
 ******************************************************************************/

package de.iiit.access.server.plugins.cache;

import de.iiit.access.common.cache.*;

import de.iiit.access.server.*;
import de.iiit.access.server.api.*;

import de.iiit.xmlconfig.*;
import de.iiit.cache.*;

/** This cache can be loaded into the AccessServer as a plug-in to accelerate the
 * evaluation of expressions.
 * @version $Revision: 1.10 $ $Date: 2003/04/13 20:28:01 $
 */
public class SimpleCache implements CachePluginIf
{
    /** CVS Version Tag */
    private static final String vcid = "$Id: SimpleCache.java,v 1.10 2003/04/13 20:28:01 joerg Exp $";

    private static final String INVALIDATION_TIMEOUT = "InvalidationTimeout";
    private static final String LRU_TIMEOUT          = "LRUTimeout";
    private static final String SLEEP_TIME           = "SleepTime";
    
    private int invalidationTimeout;
    private int lruTimeout;
    private int sleepTime;
    private boolean running = true;
    private boolean ignoreCase;
    
    UserRightsCache cache = null;
    
    /** Creates a new instance of SimpleCachePlugin */
    public SimpleCache()
    {
    }
    
    /** Initializes the cache
     * @param config the configuration of the cache. Currently these parameters are
     * recognized:
     * <PRE>
     * InvalidationTimeout - after this period of time any elements in the cache will
     *                      be ignored to assure that changes in the rights will be recognized.
     * LRUTimeout          - after this period of time an unused cache for a specific user will
     *                      be deleted. It does not make any sense to set this timeout
     *                      higher than the invalidation timeout.
     * SleepTime           - The time to sleep between to runs of the cache cleaner.
     * </PRE>
     */    
    public void initialize(Configuration config)
    {
        invalidationTimeout = Integer.parseInt(config.getAttribute(INVALIDATION_TIMEOUT, "1800")) * 1000; // 30 Min
        lruTimeout          = Integer.parseInt(config.getAttribute(LRU_TIMEOUT         , "1800")) * 1000; // 30 Min
        sleepTime           = Integer.parseInt(config.getAttribute(LRU_TIMEOUT         ,   "10")) * 1000; // 10 Sec   

        ignoreCase = AccessServer.getIgnoreCase();
    }
    
    /** Starts the cleaner thread. This method is called by the AccessServer after the
     * initialization of all sub-moduls.
     */    
    public void start()
    {
        cache = new UserRightsCache(lruTimeout, invalidationTimeout, sleepTime);
    }
    
    /** Adds the result of one expression to the cache of the user.
     * @param user The name of the user
     * @param expression The expression
     * @param isAllowed The result of the expression
     */    
    public void addUserRight(String user, String expression, boolean isAllowed)
    {
        if (ignoreCase)
        {
            user = user.toLowerCase();
            expression = expression.toLowerCase();
        }
        
        cache.addUserRight(user, expression, isAllowed);
    }
    
    /** Retrieves the result of an expression from the cache.
     * @param user The name of the user for whom the result is needed.
     * @param expression The expression
     * @throws CacheFaultException if the result is not found in the cache
     * @return the result of the expression
     */    
    public boolean getUserRight(String user, String expression) throws CacheFaultException
    {
        if (ignoreCase)
        {
            user = user.toLowerCase();
            expression = expression.toLowerCase();
        }
        
        return cache.getUserRight(user, expression);
    }
    
    /** This method is called by the AccessServer when the background threads should
     * stop because of a shutdown of the AccessServer itself.
     */
    public void shutdown()
    {
        if (cache != null)
            cache.shutdown();
    }
    
}

/**
 * $Log: SimpleCache.java,v $
 * Revision 1.10  2003/04/13 20:28:01  joerg
 * Package structure modified
 *
 * Revision 1.9  2003/04/13 20:16:41  joerg
 * Package structure modified
 *
 * Revision 1.8  2003/01/04 17:15:43  joerg
 * Zus鋞zliche Config-Option IgnoreCase
 *
 * Revision 1.7  2003/01/01 21:04:17  joerg
 * Copyright-Statement aktualisiert
 *
 * Revision 1.6  2002/12/24 21:04:33  joerg
 * Umbau der Paketstruktur
 * iiitLdapPlugin integriert
 * JavaDoc-Kommentare weiter vervollstaendigt.
 *
 * Revision 1.5  2002/12/23 11:29:35  joerg
 * start()- und shutdown()-Methode hinzugefuegt.
 *
 * Revision 1.4  2002/12/23 09:58:05  joerg
 * Klasse umbenannt in SimpleCachePlugin
 *
 * Revision 1.3  2002/12/22 20:45:12  joerg
 * shutdown()-Methode eingebaut
 *
 * Revision 1.2  2002/12/22 16:58:13  joerg
 * no message
 *
 * Revision 1.1  2002/12/19 15:24:23  joerg
 * Reparatur des CVS-Repositories
 *
 * Revision 1.3  2002/12/09 19:29:17  joerg
 * Versionsdaten in allen JavaDoc-Klassenbeschreibungen ergaenzt
 *
 * Revision 1.2  2002/12/09 16:32:26  joerg
 * JavaDoc Kommentare ergaenzt
 *
 * Revision 1.1  2002/11/19 20:23:22  joerg
 * Eingebautes Cache-Plugin fuer den AccessServer
 *
 */