hibernate-3.1.3-all-src.zip 面向对象的访问数据库工具

				//$Id: C3P0ConnectionProvider.java 6463 2005-04-19 15:39:07Z steveebersole $
				package org.hibernate.connection;
				
				import java.sql.Connection;
				import java.sql.SQLException;
				import java.util.Properties;
				
				import javax.sql.DataSource;
				import org.apache.commons.logging.Log;
				import org.apache.commons.logging.LogFactory;
				
				import com.mchange.v2.c3p0.PoolConfig;
				import com.mchange.v2.c3p0.DataSources;
				
				import org.hibernate.HibernateException;
				import org.hibernate.cfg.Environment;
				import org.hibernate.util.PropertiesHelper;
				import org.hibernate.util.ReflectHelper;
				
				/**
				 * A connection provider that uses a C3P0 connection pool. Hibernate will use this by
				 * default if the hibernate.c3p0.* properties are set.
				 * @see ConnectionProvider
				 * @author various people
				 */
				public class C3P0ConnectionProvider implements ConnectionProvider {
				
					private DataSource ds;
					private Integer isolation;
					private boolean autocommit;
				
					private static final Log log = LogFactory.getLog(C3P0ConnectionProvider.class);
				
					public Connection getConnection() throws SQLException {
						final Connection c = ds.getConnection();
						if (isolation!=null) c.setTransactionIsolation( isolation.intValue() );
						if ( c.getAutoCommit()!=autocommit ) c.setAutoCommit(autocommit);
						return c;
					}
				
					public void closeConnection(Connection conn) throws SQLException {
						conn.close();
					}
				
					public void configure(Properties props) throws HibernateException {
						String jdbcDriverClass = props.getProperty(Environment.DRIVER);
						String jdbcUrl = props.getProperty(Environment.URL);
						Properties connectionProps = ConnectionProviderFactory.getConnectionProperties(props);
				
						log.info( "C3P0 using driver: " + jdbcDriverClass + " at URL: " + jdbcUrl );
						log.info( "Connection properties: " + PropertiesHelper.maskOut(connectionProps, "password") );
						
						autocommit = PropertiesHelper.getBoolean(Environment.AUTOCOMMIT, props);
						log.info("autocommit mode: " + autocommit);
				
						if (jdbcDriverClass==null) {
							log.warn("No JDBC Driver class was specified by property " + Environment.DRIVER);
						}
						else {
							try {
								Class.forName(jdbcDriverClass);
							}
							catch (ClassNotFoundException cnfe) {
								try {
									ReflectHelper.classForName(jdbcDriverClass);
								}
								catch (ClassNotFoundException e) {
									String msg = "JDBC Driver class not found: " + jdbcDriverClass;
									log.fatal(msg, e);
									throw new HibernateException(msg, e);
								}
							}
						}
				
						try {
				
							int minPoolSize = PropertiesHelper.getInt(Environment.C3P0_MIN_SIZE, props, 1);
							int maxPoolSize = PropertiesHelper.getInt(Environment.C3P0_MAX_SIZE, props, 100);
							int maxIdleTime = PropertiesHelper.getInt(Environment.C3P0_TIMEOUT, props, 0);
							int maxStatements = PropertiesHelper.getInt(Environment.C3P0_MAX_STATEMENTS, props, 0);
							int acquireIncrement = PropertiesHelper.getInt(Environment.C3P0_ACQUIRE_INCREMENT, props, 1);
							int idleTestPeriod = PropertiesHelper.getInt(Environment.C3P0_IDLE_TEST_PERIOD, props, 0);
				
							PoolConfig pcfg = new PoolConfig();
							pcfg.setInitialPoolSize(minPoolSize);
							pcfg.setMinPoolSize(minPoolSize);
							pcfg.setMaxPoolSize(maxPoolSize);
							pcfg.setAcquireIncrement(acquireIncrement);
							pcfg.setMaxIdleTime(maxIdleTime);
							pcfg.setMaxStatements(maxStatements);
							pcfg.setIdleConnectionTestPeriod(idleTestPeriod);
				
							/*DataSource unpooled = DataSources.unpooledDataSource(
								jdbcUrl, props.getProperty(Environment.USER), props.getProperty(Environment.PASS)
							);*/
							DataSource unpooled = DataSources.unpooledDataSource(jdbcUrl, connectionProps);
							ds = DataSources.pooledDataSource(unpooled, pcfg);
				
						}
						catch (Exception e) {
							log.fatal("could not instantiate C3P0 connection pool", e);
							throw new HibernateException( "Could not instantiate C3P0 connection pool", e );
						}
				
						String i = props.getProperty(Environment.ISOLATION);
						if (i==null) {
							isolation=null;
						}
						else {
							isolation = new Integer(i);
							log.info("JDBC isolation level: " + Environment.isolationLevelToString( isolation.intValue() ) );
						}
				
					}
				
					public void close() {
						try {
							DataSources.destroy(ds);
						}
						catch (SQLException sqle) {
							log.warn("could not destroy C3P0 connection pool", sqle);
						}
					}
				
					/**
					 * @see ConnectionProvider#supportsAggressiveRelease()
					 */
					public boolean supportsAggressiveRelease() {
						return false;
					}
				
				}