class ICBCode implements ImmutableBean, Serializable {

  public static ICBCode of(final int code) {
    if ((code < 1000) || (code > 9999)) {
      throw new IllegalArgumentException("Code out of range: " + code);
    }
    return ICBCode.of(Integer.toString(code));
  }

  @ImmutableConstructor private  ICBCode(final String code);

}