public Builder setBuyItem(JSystemPiqi.buy_item_request value) {
        if (buyItemBuilder_ == null) {
          if (value == null) {
            throw new NullPointerException();
          }
          buyItem_ = value;
          onChanged();
        } else {
          buyItemBuilder_.setMessage(value);
        }
        bitField0_ |= 0x00000001;
        return this;
      }