public void setFieldValue(_Fields field, Object value) {
    switch (field) {
      case USERNAME:
        if (value == null) {
          unsetUsername();
        } else {
          setUsername((String) value);
        }
        break;

      case PASSWORD:
        if (value == null) {
          unsetPassword();
        } else {
          setPassword((String) value);
        }
        break;
    }
  }