code: public NutValidate ready() {
          Collections.sort(items, new Comparator<NutValidator>() {
              public int compare(NutValidator v1, NutValidator v2) {
                  return v1.order() - v2.order();
              }
          });
          return this;
      }
docs: 根据检查器的优先顺序，重新调整检查列表
  
  @return 自身以便链式赋值