code: public GraphHopper setDataReaderFile(String dataReaderFileStr) {
          ensureNotLoaded();
          if (isEmpty(dataReaderFileStr))
              throw new IllegalArgumentException("Data reader file cannot be empty.");
  
          dataReaderFile = dataReaderFileStr;
          return this;
      }
docs: This file can be any file type supported by the DataReader. E.g. for the OSMReader it is the
  OSM xml (.osm), a compressed xml (.osm.zip or .osm.gz) or a protobuf file (.pbf)