001/*
002 * HA-JDBC: High-Availability JDBC
003 * Copyright (c) 2004-2007 Paul Ferraro
004 * 
005 * This library is free software; you can redistribute it and/or modify it 
006 * under the terms of the GNU Lesser General Public License as published by the 
007 * Free Software Foundation; either version 2.1 of the License, or (at your 
008 * option) any later version.
009 * 
010 * This library is distributed in the hope that it will be useful, but WITHOUT
011 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 
012 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License 
013 * for more details.
014 * 
015 * You should have received a copy of the GNU Lesser General Public License
016 * along with this library; if not, write to the Free Software Foundation, 
017 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
018 * 
019 * Contact: ferraro@users.sourceforge.net
020 */
021package net.sf.hajdbc.cache;
022
023import java.sql.Connection;
024import java.sql.SQLException;
025
026import net.sf.hajdbc.Balancer;
027import net.sf.hajdbc.Database;
028import net.sf.hajdbc.DatabaseProperties;
029import net.sf.hajdbc.Dialect;
030
031/**
032 * DatabaseMetaDataCache implementation that eagerly caches data when first flushed.
033 * To be used when performance more of a concern than memory usage.
034 * 
035 * @author Paul Ferraro
036 * @since 2.0
037 */
038public class EagerDatabaseMetaDataCache<D> extends AbstractDatabaseMetaDataCache
039{
040        private volatile DatabaseProperties properties;
041        private final Balancer<D> balancer;
042        
043        public EagerDatabaseMetaDataCache(Dialect dialect, Balancer<D> balancer)
044        {
045                super(dialect);
046
047                this.balancer = balancer;
048        }
049        
050        /**
051         * @see net.sf.hajdbc.DatabaseMetaDataCache#flush()
052         */
053        @Override
054        public void flush() throws SQLException
055        {
056                Database<D> database = this.balancer.next();
057                
058                this.setDatabaseProperties(database.connect(database.createConnectionFactory()));
059        }
060
061        /**
062         * @see net.sf.hajdbc.DatabaseMetaDataCache#getDatabaseProperties(java.sql.Connection)
063         */
064        @Override
065        public synchronized DatabaseProperties getDatabaseProperties(Connection connection) throws SQLException
066        {
067                if (this.properties == null)
068                {
069                        this.setDatabaseProperties(connection);
070                }
071                
072                return this.properties;
073        }
074        
075        private synchronized void setDatabaseProperties(Connection connection) throws SQLException
076        {
077                this.properties = new EagerDatabaseProperties(connection.getMetaData(), this.factory, this.dialect);
078        }
079}