code: public void setFields(String fields) {
  
          String searchPage = getJsp().getRequest().getParameter("searchPage");
          if (CmsStringUtil.isEmptyOrWhitespaceOnly(searchPage) && CmsStringUtil.isEmptyOrWhitespaceOnly(fields)) {
              throw new CmsIllegalStateException(
                  org.opencms.workplace.search.Messages.get().container(
                      org.opencms.workplace.search.Messages.ERR_VALIDATE_SEARCH_PARAMS_0));
          }
          m_searchParams.setFields(CmsStringUtil.splitAsList(fields, ","));
      }
docs: Sets the fields parameter value.<p>
  
  @param fields the fields parameter value to set