Bug 182680 Use feature of new Aggregation framework of Data Engine.
DataEngine will implement new aggregation framework in 2.2.0RC0. After the implementation is finished Engine should go ahead to use new column bindings in definition of map/highlight.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/adapter/ExpressionUtil.java
/**
	 * When a TopN/TopPercent/BottomN/BottomPercent ConditionalExpression is
	 * set, transform it to
	 * Total.TopN/Total.TopPercent/Total.BottomN/Total.BottomPercent
	 * aggregations with "isTrue" operator.
	 * 
	 * @param ce
	 * @return
	 */
	public static IConditionalExpression transformConditionalExpression(
			IConditionalExpression ce )
	{
		String prefix = null;
		
		switch ( ce.getOperator( ) )
		{
			case IConditionalExpression.OP_TOP_N :
				prefix = "Total.isTopN";
				break;
			case IConditionalExpression.OP_TOP_PERCENT :
				prefix = "Total.isTopNPercent";
				break;
			case IConditionalExpression.OP_BOTTOM_N :
				prefix = "Total.isBottomN";
				break;
			case IConditionalExpression.OP_BOTTOM_PERCENT :
				prefix = "Total.isBottomNPercent";
				break;
		}