code: @Nullable
    public static ZonedDateTime getDateTimeFromRFC822 (@Nullable final String sDate)
    {
      if (StringHelper.hasNoText (sDate))
        return null;
  
      final WithZoneId aPair = extractDateTimeZone (sDate.trim ());
      return parseZonedDateTimeUsingMask (RFC822_MASKS, aPair.getString (), aPair.getZoneId ());
    }
docs: Parses a Date out of a String with a date in RFC822 format. <br>
  It parsers the following formats:
  <ul>
  <li>"EEE, dd MMM uuuu HH:mm:ss z"</li>
  <li>"EEE, dd MMM uuuu HH:mm z"</li>
  <li>"EEE, dd MMM uu HH:mm:ss z"</li>
  <li>"EEE, dd MMM uu HH:mm z"</li>
  <li>"dd MMM uuuu HH:mm:ss z"</li>
  <li>"dd MMM uuuu HH:mm z"</li>
  <li>"dd MMM uu HH:mm:ss z"</li>
  <li>"dd MMM uu HH:mm z"</li>
  </ul>
  <p>
  Refer to the java.text.SimpleDateFormat javadocs for details on the format
  of each element.
  </p>
  
  @param sDate
  string to parse for a date. May be <code>null</code>.
  @return the Date represented by the given RFC822 string. It returns
  <b>null</b> if it was not possible to parse the given string into a
  {@link ZonedDateTime} or if the passed {@link String} was
  <code>null</code>.