code: public String check(QueryRootNode aqt) throws IOException, RepositoryException
     {
        String stmt = getFulltextStatement(aqt);
        if (stmt == null)
        {
           // no spellcheck operation in query
           return null;
        }
        return spellChecker.suggest(stmt);
     }
docs: {@inheritDoc}
  
  @throws RepositoryException