propertytable.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: PropertyTable.java,v 1.11 2003/04/13 20:16:42 joerg Exp $
 ******************************************************************************/

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

import de.iiit.jdbc.*;

/** Every database controlled by the cache manager will contain a property table.
 * These table can be used like property files, they contain records with pairs of
 * key and values. Until now they will be used only to store the number of the next
 * cache table to create.
 */
public class PropertyTable
{
    /** CVS Version Tag */
    private static final String vcid = "$Id: PropertyTable.java,v 1.11 2003/04/13 20:16:42 joerg Exp $";

    private static final String propertyTable = "properties";

    private static final String createStmt = 
        "create table " + propertyTable + "("       +
            "property   varchar(255) primary key, " +
            "value      varchar(255))";
    
    private static final String selectStmt = 
        "select value " + 
            "from " + propertyTable + " " + 
            "where property = ?";
    
    private static final String searchStmt = 
        "select count(*) " + 
            "from " + propertyTable + " " + 
            "where property = ?";
    
    private static final String insertStmt = 
        "insert into " + propertyTable + " " + 
            "(property, value) " + 
            "values (?, ?)";
    
    private static final String updateStmt = 
        "update " + propertyTable + " " + 
            "set value = ? " + 
            "where property = ?";
    
    /** Creates a new instance of PropertyTable */
    private PropertyTable()
    {
    }

    /** Creates a new property table
     * @param pool The database handle to use
     * @throws JdbcException if a JDBC error occurs
     * @return true if table had to be created, false is table was already there
     */
    public static boolean createPropertyTable(JdbcConnectionPool pool) throws JdbcException
    {
        boolean result = false;
        
        JdbcDatabaseMetaData md = pool.getMetaData();
        JdbcResultSet rs = md.getTables(null, null, propertyTable, new String[] { "TABLE" });

        if (! rs.next())
        {
            result = true;
            JdbcStatement stmt = pool.createStatement();

            stmt.execute(createStmt);
            stmt.close();
        }
        
        rs.close();

        return result;
    }
    
    /** Retrieves one property record
     * @param pool The database handle to use
     * @param property The name of the property to search for
     * @throws JdbcException if a JDBC error occurs
     * @return the value of the property or null if no property with the given name was found.
     */    
    public static String selectProperty(JdbcConnectionPool pool, String property) throws JdbcException
    {
        String result = null;

        JdbcPreparedStatement select = pool.prepareStatement(selectStmt);    
        
        select.setString(1, property);

        JdbcResultSet rs = select.executeQuery();
                            
        if (rs.first())
            result = rs.getString(1);

        rs.close();
        select.close();

        return result;
    }

    /** Retrieves one property record
     * @param pool The database handle to use
     * @param property The name of the property to search for
     * @param defaultValue a default value.
     * @throws JdbcException if a JDBC error occurs
     * @return the value of the property or null if no property with the given name was found.
     */    
    public static String selectProperty(JdbcConnectionPool pool, String property, String defaultValue) throws JdbcException
    {
        String result = selectProperty(pool, property);
        
        if (result == null)
            result = defaultValue;

        return result;
    }

    /** Test whether a property with a given name is there
     * @param pool The database handle to use
     * @param property The name of the property to search for
     * @throws JdbcException if a JDBC error occurs
     * @return True if the property was found, false if not.
     */    
    public static boolean searchProperty(JdbcConnectionPool pool, String property) throws JdbcException
    {
        JdbcPreparedStatement search = pool.prepareStatement(searchStmt);       
        
        search.setString(1, property);
            
        JdbcResultSet rs = search.executeQuery();
                            
        rs.first();
        int count = rs.getInt(1);

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

        return (count != 0);
    }

    /** Inserts a new record into the property table
     * @param pool The database handle to use
     * @param property The name of the property
     * @param value The value of the property
     * @throws JdbcException if a JDBC error occurs
     */    
    public static void insertProperty(JdbcConnectionPool pool, String property, String value) throws JdbcException
    {
        JdbcPreparedStatement insert = pool.prepareStatement(insertStmt);
        
        insert.setString(1, property);
        insert.setString(2, value);
        insert.executeUpdate();

        insert.close();
    }

    /** Updates a record in the property table
     * @param pool The database handle to use
     * @param property The name of the property
     * @param value The value of the property
     * @throws JdbcException if a JDBC error occurs
     */    
    public static void updateProperty(JdbcConnectionPool pool, String property, String value) throws JdbcException
    {
        JdbcPreparedStatement update = pool.prepareStatement(updateStmt);
        
        update.setString(1, value);
        update.setString(2, property);
        update.executeUpdate();

        update.close();
    }

    /** Writes a record into the property table. If a record with the given name is
     * already there, it will be updated. Otherwise a new record will be inserted.
     * @param pool The database handle to use
     * @param property The name of the property
     * @param value The value of the property
     * @throws JdbcException if a JDBC error occurs
     */    
    public static void writeProperty(JdbcConnectionPool pool, String property, String value) throws JdbcException
    {
        if (! searchProperty(pool, property))
            insertProperty(pool, property, value);
        else
            updateProperty(pool, property, value);
    }
}

/**
 * $Log: PropertyTable.java,v $
 * Revision 1.11  2003/04/13 20:16:42  joerg
 * Package structure modified
 *
 * Revision 1.10  2003/01/01 21:04:18  joerg
 * Copyright-Statement aktualisiert
 *
 * Revision 1.9  2002/12/27 16:39:33  joerg
 * Neue Methode selectProperty(pool, property, defaultValue)
 *
 * Revision 1.8  2002/12/23 11:28:23  joerg
 * no message
 *
 * Revision 1.7  2002/12/21 19:55:03  joerg
 * Nicht mehr benoetigte Methoden entfernt, interne Methoden auf
 * private oder protected geaendert.
 * JavaDoc Kommentare ergaenzt.
 *
 * Revision 1.6  2002/12/19 15:54:33  joerg
 * Paket umbenannt in iiitLdapPlugin
 *
 * Revision 1.5  2002/12/08 16:09:46  joerg
 * Paket-Struktur ueberarbeitet
 *
 * Revision 1.4  2002/11/21 21:49:45  joerg
 * Umstellung auf JdbcConnectionPool
 *
 * 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
 *
 */