code: public final String formatDin5008International(final PhoneNumberInterface pphoneNumberData) {
      final StringBuilder resultNumber = new StringBuilder();
      if (isPhoneNumberNotEmpty(pphoneNumberData)) {
        resultNumber.append('+').append(pphoneNumberData.getCountryCode()).append(' ');
        if (StringUtils.isNotBlank(pphoneNumberData.getAreaCode())) {
          resultNumber.append(pphoneNumberData.getAreaCode()).append(' ');
        }
        resultNumber.append(pphoneNumberData.getLineNumber());
        if (StringUtils.isNotBlank(pphoneNumberData.getExtension())) {
          resultNumber.append('-');
          resultNumber.append(pphoneNumberData.getExtension());
        }
      }
      return StringUtils.trimToNull(resultNumber.toString());
    }
docs: format phone number in DIN 5008 international format.
  
  @param pphoneNumberData phone number to format
  @return formated phone number as String