code: private static String _constructWardenMetricExpression(String relativeStart, PrincipalUser user, PolicyCounter counter) {
          assert (user != null) : "User cannot be null.";
          assert (counter != null) : "Counter cannot be null.";
          assert (relativeStart != null) : "Relative start cannot be null.";
  
          String metricName = counter.getMetricName();
          String userName = user.getUserName();
  
          if ("sum".equals(counter.getAggregator())) {
              return MessageFormat.format("INTEGRAL(ZEROIFMISSINGSUM({0}:argus.custom:{1}'{'user={2},host=*'}':{3}))", relativeStart, metricName,
                  userName, counter.getAggregator());
          } else {
              return MessageFormat.format("{0}:argus.custom:{1}'{'user={2},host=*'}':{3}", relativeStart, metricName, userName,
                  counter.getAggregator());
          }
      }
docs: ~ Methods **************************************************************************************************************************************