public static <T1, T2> Comparator<T1> getNullSafeCaseInsensitiveComparator(
            final Function<T1, T2> extractor1,
            final Function<T2, String> extractor2) {
        return getNullSafeComparator(
                extractor1,
                extractor2,
                Comparator.nullsFirst(String.CASE_INSENSITIVE_ORDER));
    }
Creates a null safe case-insensitive comparator that can work with stuff like
getDocRef().getName()
stroom-util-shared/src/main/java/stroom/util/shared/CompareUtil.java