question: public static PronghornStage findStageByPath ( GraphManager m , int ... path ) { int ordinal = path [ 0 ] ; int i = 0 ; int limit = m . stageIdToStage . length ; while ( i < limit ) { if ( null != m . stageIdToStage [ i ] ) { if ( - 1 == m . multInputIds [ m . stageIdToInputsBeginIdx [ m . stageIdToStage [ i ] . stageId ] ] ) { if ( -- ordinal <= 0 ) { return findStageByPath ( m , m . stageIdToStage [ i ] , 1 , path ) ; } } } i ++ ; } throw new UnsupportedOperationException ( "Unable to find ordinal input stage of " + path [ 0 ] ) ; }
target:  Start with ordinal selection of input stages then ordinal selection of each output ring there after. TODO: do generic return that extends pronghornStage