code: public static String stream2compStreamName(String old) {
          String[] parts = old.split(DELIM);
          if (parts.length >= 7) {
              parts[0] = MetaType.COMPONENT_STREAM.getV() + parts[0].charAt(1);
              //parts[parts.length - 3] = EMPTY; retain stream name
              parts[parts.length - 4] = "0"; // task
              parts[parts.length - 1] = getMergeMetricName(parts[parts.length - 1]);
          }
          return concat(parts);
      }
docs: converts a task metric name to a component-level stream metric name