code: public ExecutorLoadBalancingConfig<GROUP> useEnumOrdinalPrioritizer(Class<GROUP> groupClass) {
          if(!groupClass.isEnum()) {
              throw new IllegalArgumentException("The group class "+groupClass+" is not an enum");
          }
          groupPrioritizer = new EnumOrdinalPrioritizer<GROUP>();
          return this;
      }
docs: Use this if you have an enum used for your group type that defines the priority of a task and
  you ALWAYS want to execute high priority items over low priority items.  You should really
  check out the <code>useLoadBalancedEnumOrdinalPrioritizer</code> which works similarly but
  prevents starvation of low priority items by allowing them to run some of the time
  
  @param groupClass
  @return