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
* For each group unit, it has its start row index and end row index, and
	 * then the total index will be the group unit number*2.
	 * 
	 * @param groupLevel
	 * @return int[]
	 * @throws DataException
	 */
	public int[] getGroupStartAndEndIndex( int groupLevel )
			throws DataException
	{
		if ( groupLevel == 0 )
		{
			return new int[]{
					0,
					this.groupCalculationUtil.getResultSetCache( ).getCount( )
			};
		}
		int unitCountInOneGroup = this.groups[groupLevel - 1].size( );
		if ( unitCountInOneGroup == 1 )
		{
			return new int[]{
					0,
					this.groupCalculationUtil.getResultSetCache( ).getCount( )
			};
		}
		else
		{
			int[] unitInfo = new int[unitCountInOneGroup * 2];
			for ( int i = 0; i < unitCountInOneGroup; i++ )
			{