datasources.java

c3p0数据库连接池实现源码

/*
 * Distributed as part of c3p0 v.0.9.1-pre6
 *
 * Copyright (C) 2005 Machinery For Change, Inc.
 *
 * Author: Steve Waldman <[e-mail]>
 *
 * This library is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License version 2.1, as 
 * published by the Free Software Foundation.
 *
 * This software 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this software; see the file LICENSE.  If not, write to the
 * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 */


package com.mchange.v2.c3p0;

import com.mchange.v2.log.*;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyVetoException;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import java.sql.SQLException;
import javax.sql.DataSource;
import javax.sql.ConnectionPoolDataSource;
import com.mchange.v2.sql.SqlUtils;
import com.mchange.v2.beans.BeansUtils;

/**
 *  <p>A simple factory class for creating DataSources. Generally, users will call <tt>DataSources.unpooledDataSource()</tt> to get
 *  a basic DataSource, and then get a pooled version by calling <tt>DataSources.pooledDataSource()</tt>.</p>
 *
 *  <p>Most users will not need to worry about configuration details. If you want to use a PreparedStatement cache, be sure to call
 *  the version of <tt>DataSources.pooledDataSource()</tt> that accepts a <tt>statement_cache_size</tt> parameter, and set that to
 *  be a number (much) greater than zero. (For maximum performance, you would set this to be several times the number kinds of 
 *  PreparedStatements you expect your application to use.)</p>
 *
 * <p>For those interested in detailed configuration, note that c3p0 pools can be configured by explicit method calls on PoolConfig objects,
 * by defining System properties, or by defining a <tt>c3p0.properties</tt> file in your resource path. See {@link com.mchange.v2.c3p0.PoolConfig}
 * for details.</p>
 *
 */
public final class DataSources
{
    final static MLogger logger = MLog.getLogger( DataSources.class );

    final static Set WRAPPER_CXN_POOL_DATA_SOURCE_OVERWRITE_PROPS; //22 -- includes factory class location
    final static Set POOL_BACKED_DATA_SOURCE_OVERWRITE_PROPS; //2 -- includes factory class location, excludes pool-owner id token

    static
    {
	// As of c3p0-0.9.1
	//
	// This list is no longer updated, as the PoolConfig approach to setting up DataSources
	// is now deprecated. (This was getting to be hard to maintain as new config properties
	// were added.)
	String[] props = new String[]
	{
	    "checkoutTimeout", //1 
	    "acquireIncrement",  //2
	    "acquireRetryAttempts", //3
	    "acquireRetryDelay", //4
	    "autoCommitOnClose", //5
	    "connectionTesterClassName", //6
	    "forceIgnoreUnresolvedTransactions", //7
	    "idleConnectionTestPeriod", //8
	    "initialPoolSize", //9
	    "maxIdleTime", //10
	    "maxPoolSize", //11
	    "maxStatements", //12
	    "maxStatementsPerConnection", //13
	    "minPoolSize", //14
	    "propertyCycle", //15
	    "breakAfterAcquireFailure", //16
	    "testConnectionOnCheckout", //17
	    "testConnectionOnCheckin", //18
	    "usesTraditionalReflectiveProxies", //19
	    "preferredTestQuery", //20
	    "automaticTestTable", //21
	    "factoryClassLocation" //22
	};

	WRAPPER_CXN_POOL_DATA_SOURCE_OVERWRITE_PROPS = Collections.unmodifiableSet( new HashSet( Arrays.asList( props ) ) );

	// As of c3p0-0.9.1
	//
	// This list is no longer updated, as the PoolConfig approach to setting up DataSources
	// is now deprecated. (This was getting to be hard to maintain as new config properties
	// were added.)
	props = new String[]
	{
	    "numHelperThreads",
	    "factoryClassLocation"
	};

	POOL_BACKED_DATA_SOURCE_OVERWRITE_PROPS = Collections.unmodifiableSet( new HashSet( Arrays.asList( props ) ) );
    }

    /**
     * Defines an unpooled DataSource on the specified JDBC URL.
     */
    public static DataSource unpooledDataSource(String jdbcUrl) throws SQLException
    { 
	DriverManagerDataSource out = new DriverManagerDataSource();
	out.setJdbcUrl( jdbcUrl );
	return out;
    }

    /**
     * Defines an unpooled DataSource on the specified JDBC URL, authenticating with a username and password.
     */
    public static DataSource unpooledDataSource(String jdbcUrl, String user, String password) throws SQLException
    {
	Properties props = new Properties();
	props.put(SqlUtils.DRIVER_MANAGER_USER_PROPERTY, user);
	props.put(SqlUtils.DRIVER_MANAGER_PASSWORD_PROPERTY, password);
	return unpooledDataSource( jdbcUrl, props ); 
    }

    /**
     * Defines an unpooled DataSource on the specified JDBC URL.
     *
     *  @param driverProps the usual DriverManager properties for your JDBC driver
     *         (e.g. "user" and "password" for all drivers that support
     *         authentication)
     * 
     *  @see java.sql.DriverManager
     */
    public static DataSource unpooledDataSource(String jdbcUrl, Properties driverProps) throws SQLException
    {
	DriverManagerDataSource out = new DriverManagerDataSource();
	out.setJdbcUrl( jdbcUrl );
	out.setProperties( driverProps );
	return out;
    }

    /**
     * <p>Creates a pooled version of an unpooled DataSource using default configuration information.</p>
     * <p><b>NOTE:</b> By default, statement pooling is turned off, because for simple databases that do
     *                 not pre-parse and optimize PreparedStatements, statement caching is a net
     *                 performance loss. But if your database <i>does</i> optimize PreparedStatements
     *                 you'll want to turn StatementCaching on via {@link #pooledDataSource(javax.sql.DataSource, int)}.</p>
     *  @return a DataSource that can be cast to a {@link PooledDataSource} if you are interested in pool statistics
     */
    public static DataSource pooledDataSource( DataSource unpooledDataSource ) throws SQLException
    { return pooledDataSource( unpooledDataSource, null, (Map) null ); }

    /**
     * <p>Creates a pooled version of an unpooled DataSource using default configuration information 
     *    and the specified startement cache size.
     *    Use a value greater than zero to turn statement caching on.</p>
     *
     *  @return a DataSource that can be cast to a {@link PooledDataSource} if you are interested in pool statistics
     */
    public static DataSource pooledDataSource( DataSource unpooledDataSource, int statement_cache_size ) throws SQLException
    {
// 	PoolConfig pcfg = new PoolConfig();
// 	pcfg.setMaxStatements( statement_cache_size );

	Map overrideProps = new HashMap();
	overrideProps.put( "maxStatements", new Integer( statement_cache_size ) );
	return pooledDataSource( unpooledDataSource, null, overrideProps );
    }

    /**
     * <p>Creates a pooled version of an unpooled DataSource using configuration 
     *    information supplied explicitly by a {@link com.mchange.v2.c3p0.PoolConfig}.
     *
     *  @return a DataSource that can be cast to a {@link PooledDataSource} if you are interested in pool statistics
     *
     *  @deprecated if you want to set properties programmatically, please construct a ComboPooledDataSource and
     *              set its properties rather than using PoolConfig
     */
    public static DataSource pooledDataSource( DataSource unpooledDataSource, PoolConfig pcfg ) throws SQLException
    {
	try
	    {
		WrapperConnectionPoolDataSource wcpds = new WrapperConnectionPoolDataSource();
		wcpds.setNestedDataSource( unpooledDataSource );
		
		// set PoolConfig info -- WrapperConnectionPoolDataSource properties 
		BeansUtils.overwriteSpecificAccessibleProperties( pcfg, wcpds, WRAPPER_CXN_POOL_DATA_SOURCE_OVERWRITE_PROPS );
		
		PoolBackedDataSource nascent_pbds = new PoolBackedDataSource();
		nascent_pbds.setConnectionPoolDataSource( wcpds );
		BeansUtils.overwriteSpecificAccessibleProperties( pcfg, nascent_pbds, POOL_BACKED_DATA_SOURCE_OVERWRITE_PROPS );

		return nascent_pbds;
	    }
// 	catch ( PropertyVetoException e )
// 	    {
// 		e.printStackTrace();
// 		PropertyChangeEvent evt = e.getPropertyChangeEvent();
// 		throw new SQLException("Illegal value attempted for property " + evt.getPropertyName() + ": " + evt.getNewValue());
// 	    }
 	catch ( Exception e )
 	    {
 		//e.printStackTrace();
		SQLException sqle = SqlUtils.toSQLException("Exception configuring pool-backed DataSource: " + e, e);
		if (Debug.DEBUG && Debug.TRACE >= Debug.TRACE_MED && logger.isLoggable( MLevel.FINE ) && e != sqle)
		    logger.log( MLevel.FINE, "Converted exception to throwable SQLException", e );
 		throw sqle;
 	    }
    }

    /*
    public static DataSource pooledDataSource( DataSource unpooledDataSource, String overrideDefaultUser, String overrideDefaultPassword ) throws SQLException
    {
	Map overrideProps;

	if (overrideDefaultUser != null)
	    {
		overrideProps = new HashMap();
		overrideProps.put( "overrideDefaultUser", overrideDefaultUser );
		overrideProps.put( "overrideDefaultPassword", overrideDefaultPassword );
	    }
	else
	    overrideProps = null;

	return pooledDataSource( unpooledDataSource, null, overrideProps );
    }
    */

    public static DataSource pooledDataSource( DataSource unpooledDataSource, String configName ) throws SQLException
    { return pooledDataSource( unpooledDataSource, configName, null ); }

    public static DataSource pooledDataSource( DataSource unpooledDataSource, Map overrideProps ) throws SQLException
    { return pooledDataSource( unpooledDataSource, null, overrideProps ); }

    public static DataSource pooledDataSource( DataSource unpooledDataSource, String configName, Map overrideProps ) throws SQLException
    {
	try
	    {
		WrapperConnectionPoolDataSource wcpds = new WrapperConnectionPoolDataSource(configName);
		wcpds.setNestedDataSource( unpooledDataSource );
		if (overrideProps != null)
		    BeansUtils.overwriteAccessiblePropertiesFromMap( overrideProps, 
								     wcpds, 
								     false,
								     null,
								     true,
								     MLevel.WARNING,
								     MLevel.WARNING,
								     false);
		
		PoolBackedDataSource nascent_pbds = new PoolBackedDataSource(configName);
		nascent_pbds.setConnectionPoolDataSource( wcpds );
		if (overrideProps != null)
		    BeansUtils.overwriteAccessiblePropertiesFromMap( overrideProps, 
								     wcpds, 
								     false,
								     null,
								     true,
								     MLevel.WARNING,
								     MLevel.WARNING,
								     false);

		return nascent_pbds;
	    }
// 	catch ( PropertyVetoException e )
// 	    {
// 		e.printStackTrace();
// 		PropertyChangeEvent evt = e.getPropertyChangeEvent();
// 		throw new SQLException("Illegal value attempted for property " + evt.getPropertyName() + ": " + evt.getNewValue());
// 	    }
 	catch ( Exception e )
 	    {
 		//e.printStackTrace();
		SQLException sqle = SqlUtils.toSQLException("Exception configuring pool-backed DataSource: " + e, e);
		if (Debug.DEBUG && Debug.TRACE >= Debug.TRACE_MED && logger.isLoggable( MLevel.FINE ) && e != sqle)
		    logger.log( MLevel.FINE, "Converted exception to throwable SQLException", e );
 		throw sqle;
 	    }
    }

    /**
     * <p>Creates a pooled version of an unpooled DataSource using configuration 
     *    information supplied explicitly by a Java Properties object.</p>
     *
     *  @return a DataSource that can be cast to a {@link PooledDataSource} if you are interested in pool statistics
     *  @see com.mchange.v2.c3p0.PoolConfig
     */
    public static DataSource pooledDataSource( DataSource unpooledDataSource, Properties props ) throws SQLException
    { 
	//return pooledDataSource( unpooledDataSource, new PoolConfig( props ) ); 

	Properties peeledProps = new Properties();
	for (Iterator ii = props.keySet().iterator(); ii.hasNext(); )
	    {
		String propKey = (String) ii.next();
		String propVal = props.getProperty( propKey );
		String peeledKey = (propKey.startsWith("c3p0.") ? propKey.substring(5) : propKey );
		peeledProps.put( peeledKey, propVal );
	    }
	return pooledDataSource( unpooledDataSource, null, peeledProps );
    }

    /**
     * <p>Immediately releases resources (Threads and database Connections) that are
     *    held by a C3P0 DataSource.
     *
     * <p>Only DataSources created by the poolingDataSource() method hold any
     *    non-memory resources. Calling this method on unpooled DataSources is
     *    effectively a no-op.</p>
     *
     * <p>You can safely presume that destroying a pooled DataSource that is wrapped around
     *    another DataSource created by this library destroys both the outer and the wrapped
     *    DataSource. There is no reason to hold a reference to a nested DataSource in order
     *    to explicitly destroy it.</p>
     *
     *  @see com.mchange.v2.c3p0.PoolConfig
     */
    public static void destroy( DataSource pooledDataSource ) throws SQLException
    { destroy( pooledDataSource, false ); }


    /**
     *   @deprecated forceDestroy() is no longer meaningful, as a set of pools is now
     *               directly associated with a DataSource, and not potentially shared.
     *               (This simplification was made possible by canonicalization of 
     *               JNDI-looked-up DataSources within a virtual machine.) Just use
     *               DataSources.destroy().
     *
     *   @see #destroy
     */
    public static void forceDestroy( DataSource pooledDataSource ) throws SQLException
    { destroy( pooledDataSource, true ); }

    private static void destroy( DataSource pooledDataSource, boolean force ) throws SQLException
    {
	if ( pooledDataSource instanceof PoolBackedDataSource)
	    {
		ConnectionPoolDataSource cpds = ((PoolBackedDataSource) pooledDataSource).getConnectionPoolDataSource();
		if (cpds instanceof WrapperConnectionPoolDataSource)
		    destroy( ((WrapperConnectionPoolDataSource) cpds).getNestedDataSource(), force );
	    }
	if ( pooledDataSource instanceof PooledDataSource )
	    ((PooledDataSource) pooledDataSource).close( force );
    }

    private DataSources()
    {}
}