code: static String convertToDirectoryPath(String objectName) {
      if (!Strings.isNullOrEmpty(objectName)) {
        if (!objectHasDirectoryPath(objectName)) {
          objectName += GoogleCloudStorage.PATH_DELIMITER;
        }
      }
      return objectName;
    }
docs: Converts the given object name to look like a directory path.
  If the object name already looks like a directory path then
  this call is a no-op.
  <p>
  If the object name is null or empty, it is returned as-is.
  
  @param objectName Name of the object to inspect.
  @return Directory path for the given path.