@Override
    public void add(UpgradeContext ctx, HostsType hostsType, String service,
        boolean clientOnly, ProcessingComponent pc, Map<String, String> params) {
      // !!! no-op in this case
    }
Constructor.

@param grouping
         the upgrade/downgrade grouping (not {@code null}).
ambari-server/src/main/java/org/apache/ambari/server/stack/upgrade/ClusterGrouping.java