//$Id: DriverManagerConnectionProvider.java,v 1.8.2.3 2003/10/25 11:11:45 oneovthafew Exp $package net.sf.hibernate.connection;import java.sql.Connection;import java.sql.DriverManager;import java.sql.SQLException;import java.util.ArrayList;import java.util.Iterator;import java.util.Properties;import net.sf.hibernate.HibernateException;import net.sf.hibernate.cfg.Environment;import net.sf.hibernate.util.JDBCExceptionReporter;import net.sf.hibernate.util.PropertiesHelper;import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;/** * A connection provider that uses <tt>java.sql.DriverManager</tt>. This provider * also implements a very rudimentary connection pool. * @see ConnectionProvider * @author Gavin King */public class DriverManagerConnectionProvider implements ConnectionProvider {		private String url;	private Properties connectionProps;	private Integer isolation;	private final ArrayList pool = new ArrayList();	private int poolSize;	private int checkedOut = 0;		private static final Log log = LogFactory.getLog(DriverManagerConnectionProvider.class);		public void configure(Properties props) throws HibernateException {				String driverClass = props.getProperty(Environment.DRIVER);				poolSize = PropertiesHelper.getInt(Environment.POOL_SIZE, props, 20); //default pool size 20		log.info("Using Hibernate built-in connection pool (not for production use!)");		log.info("Hibernate connection pool size: " + poolSize);				isolation = PropertiesHelper.getInteger(Environment.ISOLATION, props);		if (isolation!=null)		log.info( "JDBC isolation level: " + Environment.isolationLevelToString( isolation.intValue() ) );				if (driverClass==null) {			log.warn("no JDBC Driver class was specified by property " + Environment.DRIVER);		}		else {			try {				Class.forName(driverClass);			}			catch (ClassNotFoundException cnfe) {				String msg = "JDBC Driver class not found: " + driverClass;				log.fatal(msg);				throw new HibernateException(msg);			}		}				url = props.getProperty(Environment.URL);		if (url==null) {			String msg = "JDBC URL was not specified by property " + Environment.URL;			log.fatal(msg);			throw new HibernateException(msg);		}				connectionProps = ConnectionProviderFactory.getConnectionProperties(props);				log.info( "using driver: " + driverClass + " at URL: " + url );		log.info("connection properties: " + connectionProps);			}		public Connection getConnection() throws SQLException {				if ( log.isTraceEnabled() ) log.trace( "total checked-out connections: " + checkedOut );				synchronized (pool) {			if ( !pool.isEmpty() ) {				int last = pool.size() - 1;				if ( log.isTraceEnabled() ) {					log.trace("using pooled JDBC connection, pool size: " + last);					checkedOut++;				}				Connection pooled = (Connection) pool.remove(last);				if (isolation!=null) pooled.setTransactionIsolation( isolation.intValue() );				if ( pooled.getAutoCommit() ) pooled.setAutoCommit(false);				return pooled;			}		}				log.debug("opening new JDBC connection");		Connection conn = DriverManager.getConnection(url, connectionProps);		if (isolation!=null) conn.setTransactionIsolation( isolation.intValue() );		if ( conn.getAutoCommit() ) conn.setAutoCommit(false);		if ( log.isDebugEnabled() ) {			log.debug( "created connection to: " + url + ", Isolation Level: " + conn.getTransactionIsolation() );		}		if ( log.isTraceEnabled() ) checkedOut++;				return conn;	}		public void closeConnection(Connection conn) throws SQLException {				if ( log.isDebugEnabled() ) checkedOut--;				synchronized (pool) {			int currentSize = pool.size();			if ( currentSize < poolSize ) {				if ( log.isTraceEnabled() ) log.trace("returning connection to pool, pool size: " + (currentSize + 1) );				pool.add(conn);				return;			}		}				log.debug("closing JDBC connection");				try {			conn.close();		}		catch (SQLException sqle) {			JDBCExceptionReporter.logExceptions(sqle);			throw sqle;		}	}		protected void finalize() {		close();	}		public void close() {				log.info("cleaning up connection pool: " + url);				Iterator iter = pool.iterator();		while ( iter.hasNext() ) {			try {				( (Connection) iter.next() ).close();			}			catch (SQLException sqle) {				log.warn("problem closing pooled connection", sqle);			}		}		pool.clear();			}}