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
DataEngineContext.RESULTCLASS_STREAM );
		IResultClass resultClass = new ResultClass( stream );
		try
		{
			stream.close( );
		}
		catch ( IOException e )
		{
			throw new DataException( ResourceConstants.RD_LOAD_ERROR,
					e,
					"Result Class" );
		}
		return new ResultMetaData( resultClass );
	}
	
	/**
	 * @throws DataException
	 */
	private void prepare( ) throws DataException
	{
		if ( rowDis == null )
		{
			rowIs = context.getInputStream( queryResultID,
					subQueryID,
					DataEngineContext.EXPR_VALUE_STREAM );
			rowBis = new BufferedInputStream( rowIs );
			try
			{
				rowDis = new DataInputStream( rowBis );
				rowCount = IOUtil.readInt( rowDis );