sharedScope = null;
	public void shutdown( )	{		logger.entering( "DataEngineImpl", "shutdown" );		if ( dataSources == null )		{			// Already shutdown			logger.fine( "The data engine has already been shutdown" );			return;		}		// Close all open data sources		Collection col = dataSources.values( );		Iterator it = col.iterator( );		while ( it.hasNext( ) )		{			DataSourceRuntime ds = (DataSourceRuntime) it.next( );			try			{				closeDataSource( ds );			}			catch ( DataException e )			{				if ( logger.isLoggable( Level.FINE ) )					logger.log( Level.FINE, "The data source ("							+ ds + ") fails to shut down", e );			}		}				this.dataSourceManager.close( );				logger.logp( Level.INFO,				DataEngineImpl.class.getName( ),				"shutdown",				"Data engine shuts down" );		sharedScope = null;		dataSetDesigns = null;		dataSources = null;		logger.exiting( DataEngineImpl.class.getName( ), "shutdown" );	}