code: public Optional<Boolean> hasValidFallback(String path)
    {
      return resources.get(path) != null ? Optional.of(resources.get(path).hasValidItemFallback)
          : Optional.<Boolean> absent();
    }
docs: Returns an {@link Optional} containing a boolean indicating whether the
  resource at the given path has a valid item fallback, or
  {@link Optional#absent()} if no resource has been registered for the given
  path.