public static boolean isValidIdString(final String idString) {
        if (idString == null) {
            return false;
        } else {
            final int len = idString.length();
            if (len >= 3 && len % 3 == 0) {
                for (final char chr : idString.toCharArray()) {
                    if (!Character.isDigit(chr)) {
                        return false;
                    }
                }
                return true;
            } else {
                return false;
            }
        }
    }
Convert id into a zero padded string that has a length that is divisible by three.
The length will be the shortest possible to fit the id value.
e.g.
<ul>
   <li>{@code 1 => 001}</li>
   <li>{@code 12 => 012}</li>
   <li>{@code 123 => 123}</li>
   <li>{@code 1234 => 001234}</li>
   <li>{@code 12345678 => 012345678}</li>
</ul>
stroom-util/src/main/java/stroom/util/string/StringIdUtil.java