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/GroupCalculationUtil.java
{
	private BaseQuery query;
	private IResultClass rsMeta;
	/**
	 * Group definitions. Each entry has name of key column plus interval
	 * information. groupKeys[0] is the highest group level
	 */
	private GroupBy[] groupDefs;
	
	private ResultSetCache smartCache;
	private GroupInformationUtil groupInformationUtil;
	/*
	 * groups[level] is an ArrayList of GroupInfo objects at the specified
	 * level. Level is a 0-based group index, with 0 denoting the outermost
	 * group, etc. Example: Row GroupKey1 GroupKey2 GroupKey3 Column4 Column5 0:
	 * CHINA BEIJING 2003 Cola $100 1: CHINA BEIJING 2003 Pizza $320 2: CHINA
	 * BEIJING 2004 Cola $402 3: CHINA SHANGHAI 2003 Cola $553 4: CHINA SHANGHAI
	 * 2003 Pizza $223 5: CHINA SHANGHAI 2004 Cola $226 6: USA CHICAGO 2004
	 * Pizza $133 7: USA NEW YORK 2004 Cola $339 8: USA NEW YORK 2004 Cola $297
	 * 
	 * groups: (parent, child) LEVEL 0 LEVEL 1 LEVEL 2
	 * ============================================ 0: -,0 0,0 0,0 1: -,2 0,2
	 * 0,2 2: 1,4 1,3 3: 1,5 1,5 4: 2,6 5: 3,7
	 */
	private ResultSetPopulator resultPopoulator;
	
	/**