/** {@inheritDoc} */
 public Set<String> validateRefreshTokenScope(
     ClientRegistration clientRegistration,
     Set<String> requestedScope,
     Set<String> tokenScope,
     OAuth2Request request)
     throws ServerException, InvalidScopeException {
   return scopeValidator.scopeRequestedForRefreshToken(
       requestedScope,
       clientRegistration.getAllowedScopes(),
       tokenScope,
       clientRegistration.getDefaultScopes());
 }