docs: public String toDateStr() {
  		if (null != this.timeZone) {
  			final SimpleDateFormat simpleDateFormat = new SimpleDateFormat(DatePattern.NORM_DATE_PATTERN);
  			simpleDateFormat.setTimeZone(this.timeZone);
  			return toString(simpleDateFormat);
  		}
  		return toString(DatePattern.NORM_DATE_FORMAT);
  	}