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/GroupInformationUtil.java
* 
	 * @throws DataException
	 */
	private void checkStarted( ) throws DataException
	{
		if ( this.groupCalculationUtil.getResultSetCache( ) == null )
			throw new DataException( ResourceConstants.NO_CURRENT_ROW );
	}
	/**
	 * 
	 * @throws DataException
	 */
	private void checkHasCurrentRow( ) throws DataException
	{
		checkStarted( );
		if ( this.groupCalculationUtil.getResultSetCache( ).getCurrentResult( ) == null )
			throw new DataException( ResourceConstants.NO_CURRENT_ROW );
	}
	/**
	 * Returns the 1-based index of the outermost group in which the current row
	 * is the first row. For example, if a query contain N groups (group with
	 * index 1 being the outermost group, and group with index N being the
	 * innermost group), and this function returns a value M, it indicates that
	 * the current row is the first row in groups with indexes (M, M+1, ..., N ).
	 * 
	 * @return The 1-based index of the outermost group in which the current row
	 *         is the first row; (N+1) if the current row is not at the start of
	 *         any group;
	 */
	public int getStartingGroupLevel( ) throws DataException