code: public Fields getComponentOutputFields(String componentId, String streamId) {
          Fields ret = _componentToStreamToFields.get(componentId).get(streamId);
          if (ret == null) {
              throw new IllegalArgumentException("No output fields defined for component:stream " + componentId + ":" + streamId);
          }
          return ret;
      }
docs: Gets the declared output fields for the specified component/stream.