if ( availabeAggrList != null ) availabeAggrList.clear( ); availabeAggrList = null;
if ( availableAggrList != null ) availableAggrList.clear( ); availableAggrList = null;
	public void clear( )	{		if ( availabeAggrList != null )			availabeAggrList.clear( );		availabeAggrList = null;	}