code: public static String parseQueryFields(UriInfo uriInfo) {
          List<String> selectables = uriInfo.getQueryParameters()
                  .get(EntityFieldsScopeResolver.FIELDS_PARAM_NAME);
          StringBuilder builder = new StringBuilder();
          if (selectables != null) {
              for (int i = 0; i < selectables.size(); i++) {
                  String s = selectables.get(i);
                  if (StringUtils.isNotBlank(s)) {
                      if (!s.startsWith("(")) {
                          builder.append("(");
                      }
                      builder.append(s);
                      if (!s.endsWith(")")) {
                          builder.append(")");
                      }
                      if (i < selectables.size() - 1) {
                          builder.append(":");
                      }
                  }
              }
          }
          return builder.length() == 0 ? null : builder.toString();
      }
docs: Parse and return a BeanPathProperties format from UriInfo
  
  @param uriInfo uri info
  @return query fields