code: public static String getNotEmptyParameter(HttpServletRequest request, String paramName) {
  
          String result = request.getParameter(paramName);
          if (CmsStringUtil.isEmptyOrWhitespaceOnly(result)) {
              result = null;
          }
          return result;
      }
docs: Reads value from the request parameters,
  will return <code>null</code> if the value is not available or only white space.<p>
  
  @param request the request to read the parameter from
  @param paramName the parameter name to read
  
  @return the request parameter value for the given parameter