Bug 131011 Support running query based on report document data
Data Engine should support running a query based on data set and expression data stored in a report document. This bugzilla entry serves as a repository for design docs and notes related to this feature.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/executor/transform/group/GroupBy.java
groupBy.groupSpec = groupDefn;
		groupBy.columnIndex = columnIndex;
		groupBy.columnName = columnName;
		return groupBy;
	}
	/**
	 * Static method to create and instance of subclass of GroupBy, based on the
	 * group definition
	 * 
	 * @param groupDefn
	 * @return GroupBy
	 * @throws DataException
	 */
	static GroupBy newInstanceForRowID( GroupSpec groupDefn )
			throws DataException
	{
		assert groupDefn != null;
		GroupBy groupBy = null;
		switch ( groupDefn.getInterval( ) )
		{
			case GroupSpec.NO_INTERVAL :
				groupBy = new GroupByDistinctValue( );
				break;
			case GroupSpec.NUMERIC_INTERVAL :
				groupBy = new GroupByPositionRange( groupDefn );
				break;
			default :
				throw new DataException( ResourceConstants.BAD_GROUP_INTERVAL_TYPE_ROWID );
		}
		groupBy.groupSpec = groupDefn;