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
int startIndex = i;
				int endIndex = startIndex + 1;
				startIndex = GroupUtil.getGroupFirstRowIndex( groupLevel,
						startIndex,
						this.groups,
						this.groupCalculationUtil.getResultSetCache( ) );
				endIndex = GroupUtil.getGroupFirstRowIndex( groupLevel,
						endIndex,
						this.groups,
						this.groupCalculationUtil.getResultSetCache( ) );
				unitInfo[i * 2] = startIndex;
				unitInfo[i * 2 + 1] = endIndex;
			}
			return unitInfo;
		}
	}
	/**
	 * Do grouping, and fill group indexes
	 * 
	 * @throws DataException
	 */
	public void doGrouping( ) throws DataException
	{
		assert this.groupCalculationUtil.getResultSetCache( ) != null;
		
		groups = new ArrayList[this.groupCalculationUtil.getGroupDefn( ).length];
		if ( groups.length == 0 )
			return;
		for ( int i = 0; i < this.groupCalculationUtil.getGroupDefn( ).length; i++ )
		{