cachetable.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: CacheTable.java,v 1.15 2003/04/13 20:16:42 joerg Exp $
 ******************************************************************************/

package de.iiit.access.server.util.db.cachedb;

import de.iiit.jdbc.*;

import org.apache.log4j.Logger;

import java.util.*;

/** A cache table holds the complete result set of the expression or group it
 * belongs to. Later on, when we want to know whether someone is member of the
 * group described described by the expression, we are only interested in fact
 * whether there is a record with the name of the user or not. We will never need
 * the record itself.
 */
public class CacheTable
{
    /** CVS Version Tag */
    private static final String vcid = "$Id: CacheTable.java,v 1.15 2003/04/13 20:16:42 joerg Exp $";

    private static Logger logger = Logger.getLogger("CacheTable");
    
    /** Creates a new instance of CacheTable */
    private CacheTable()
    {
    }

    /** Creates a new empty cache table
     * @param pool The database handle to use
     * @param name The name of the table to create.
     * @throws JdbcException if a JDBC error occurs
     */    
    public static void createCacheTable(JdbcConnectionPool pool, String name) throws JdbcException
    {
        JdbcStatement stmt = pool.createStatement();

        stmt.execute("create table " + name + " (" +
                        "user varchar(255) primary key)");
        stmt.close();
    }
    
    /** Drops a cache table which is no longer needed.
     * @param pool The database handle to use
     * @param name The name of the table to drop.
     * @throws JdbcException if a JDBC error occurs
     */    
    public static void dropCacheTable(JdbcConnectionPool pool, String name) throws JdbcException
    {
        JdbcStatement stmt = pool.createStatement();

        stmt.execute("drop table " + name);
        stmt.close();
    }

    /** Inserts a list of names into an already existing cache table.
     * @param pool The database handle to use
     * @param name The name of the table to fill
     * @param set the names to insert into the table
     * @param toLower forces all data to be converted to lower case if its value is true
     * @throws JdbcException if a JDBC error occurs
     */    
    public static void insertCacheTable(JdbcConnectionPool pool, String name, Set set, boolean toLower) throws JdbcException
    {
        JdbcPreparedStatement insert = pool.prepareStatement("insert into " + name + " values (?)");
            
        Iterator i = set.iterator();

        while (i.hasNext())
        {
            String s = (String) i.next();
            
            if (toLower)
                s = s.toLowerCase();
            
            insert.setString(1, s);
            insert.executeUpdate();                
        }

        insert.close();
    }
    
    /** Searches a cache table for the name of an user.
     * @param pool The database handle to use
     * @param name The name of the table to search in
     * @param user The name of the user to search for
     * @throws JdbcException if a JDBC error occurs
     * @return true if the table contains the name, false if not.
     */    
    public static boolean searchCacheTable(JdbcConnectionPool pool, String name, String user) 
    throws JdbcException
    {
        JdbcPreparedStatement search = pool.prepareStatement("select count(*) from " + name + " where user = ?");

        search.setString(1, user);
            
        JdbcResultSet rs = search.executeQuery();
                            
        rs.first();
        int count = rs.getInt(1);

        rs.close();
        search.close();

        return (count != 0);
    }
    
    /** Searches for cache tables not contained in the index table. All found tables
     * will be dropped.
     * @param pool The database handle to use
     * @throws JdbcException if a JDBC error occurs
     */    
    public static void dropLostTables(JdbcConnectionPool pool) throws JdbcException
    {
        JdbcDatabaseMetaData md = pool.getMetaData();
        JdbcResultSet rs = md.getTables(null, null, "T%", new String[] { "TABLE" });

        Set tableNames = IndexTable.selectAllTableNames(pool);
        
        while (rs.next())
        {
            String t = rs.getString(3);
            
            if (! tableNames.contains(t))
            {
                logger.info("Dropping lost table = <" + t + ">");
                dropCacheTable(pool, t);
            }
        }

        rs.close();
    }

}

/**
 * $Log: CacheTable.java,v $
 * Revision 1.15  2003/04/13 20:16:42  joerg
 * Package structure modified
 *
 * Revision 1.14  2003/01/16 21:47:46  joerg
 * no message
 *
 * Revision 1.13  2003/01/04 17:15:43  joerg
 * Zus鋞zliche Config-Option IgnoreCase
 *
 * Revision 1.12  2003/01/01 21:04:18  joerg
 * Copyright-Statement aktualisiert
 *
 * Revision 1.11  2002/12/23 11:28:23  joerg
 * no message
 *
 * Revision 1.10  2002/12/21 19:55:04  joerg
 * Nicht mehr benoetigte Methoden entfernt, interne Methoden auf
 * private oder protected geaendert.
 * JavaDoc Kommentare ergaenzt.
 *
 * Revision 1.9  2002/12/19 15:54:33  joerg
 * Paket umbenannt in iiitLdapPlugin
 *
 * Revision 1.8  2002/12/08 16:37:33  joerg
 * Aufraeumungsarbeiten nach dem grossen Umbau
 *
 * Revision 1.7  2002/12/08 16:09:46  joerg
 * Paket-Struktur ueberarbeitet
 *
 * Revision 1.6  2002/11/21 21:49:45  joerg
 * Umstellung auf JdbcConnectionPool
 *
 * Revision 1.5  2002/11/21 09:13:05  joerg
 * Verlorene Tabellen werden jetzt nicht mehr einzeln in der
 * IndexTabelle gesucht sondern mit den vorab daraus geldenenen
 * Tabellen-Namen verglichen.
 *
 * Revision 1.4  2002/11/21 08:35:46  joerg
 * Neue Methode searchCacheTable()
 *
 * Revision 1.3  2002/11/20 20:41:29  joerg
 * Klassen fuer das HAndling der DB-Tabellen in Packages
 * de.iiit.AccessServer.db.* verschoben
 *
 * Revision 1.2  2002/11/18 22:09:00  joerg
 * CacheManager ausgelagert als PlugIn
 *
 * Revision 1.1  2002/11/18 10:17:49  joerg
 * Klassen des CacheManagers in eigenes Package verschoben
 *
 * Revision 1.1  2002/11/17 22:03:26  joerg
 * Neue Klassen fuer 2nd-level Cache
 *
 */