docs: @Transactional
      @Override
      public ExternalPortletDefinition deleteData(String fname) {
          final IPortletDefinition def = this.portletDefinitionDao.getPortletDefinitionByFname(fname);
          if (null == def) {
              return null;
          }
  
          ExternalPortletDefinition result = convert(def);
          this.portletDefinitionDao.deletePortletDefinition(def);
          return result;
      }