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/impl/document/RDLoad.java
private Map exprValueMap = new HashMap( );
	/**
	 * @param context
	 * @param queryResultID
	 * @param subQueryName
	 * @param currParentIndex
	 * @throws DataException
	 */
	RDLoad( DataEngineContext context, String queryResultID,
			String subQueryName, int currParentIndex ) throws DataException
	{
		this.context = context;
		this.queryResultID = queryResultID;
		this.subQueryName = subQueryName;
		this.version = VersionManager.getVersion( context );
		this.INT_LENGTH = IOUtil.INT_LENGTH;
		
		if ( subQueryName != null )
			this.subQueryID = subQueryName
					+ "/" + getSubQueryIndex( currParentIndex );
	}
	/**
	 * @return result meta data
	 * @throws DataException
	 */
	ResultMetaData loadResultMetaData( ) throws DataException
	{
		InputStream stream = context.getInputStream( queryResultID,
				subQueryName,