double getAggregate( int aggType )
	{
		switch ( aggType )
		{
			case AGG_MINIMUM:
			case AGG_MAXIMUM:
			case AGG_AVERAGE:
			case AGG_FIRST:
			case AGG_LAST:
				return values[0];

			case AGG_TOTAL:
				return (values[0] * values.length) ;
		}

		return Double.NaN;
	}