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.columnIndex = -1;
		return groupBy;
	}
	/**
	 * Determines if the current group key is in the same group as the key value
	 * provided in the last call. This method can be overrided in special case,
	 * for example, group on row position.
	 * 
	 * @param currentGroupKey
	 * @param previousGroupKey
	 * @param groupStartValue
	 * @param currRowPos
	 * @return boolean value
	 * @throws DataException
	 */
	boolean isInSameGroup( Object currentGroupKey, Object previousGroupKey,
			Object groupStartValue, int currRowPos ) throws DataException
	{
		return isInSameGroup( currentGroupKey, previousGroupKey );
	}
	/**
	 * Determines if the current group key is in the same group as the key value
	 * provided in the last call
	 * 
	 * @param currentGroupKey
	 * @param previousGroupKey
	 * @return boolean
	 * @throws DataException
	 */
	boolean isInSameGroup( Object currentGroupKey, Object previousGroupKey )