Bug 214196 [Automation][Compatibility]Exception occurs when preview a old crosstab with measure sorting
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/DataEngineImpl.java
/*
	 * @see org.eclipse.birt.data.engine.api.DataEngine#shutdown()
	 */
	public void shutdown( )
	{
		logger.entering( "DataEngineImpl", "shutdown" );
		if ( dataSources == null )
		{
			
			logger.fine( "The data engine has already been shutdown" );
			return;
		}
		
		if ( shutdownListenerList != null )
		{
			for ( int i = 0; i < shutdownListenerList.size( ); i++ )
			{
				( (IShutdownListener) shutdownListenerList.get( i ) ).dataEngineShutdown( );
			}
			shutdownListenerList.clear( );
		}
		
		
		Collection col = dataSources.values( );
		Iterator it = col.iterator( );
		while ( it.hasNext( ) )
		{
			DataSourceRuntime ds = (DataSourceRuntime) it.next( );
			try