class MapperUtils {

    public static <I, O> List<O> mapCollection(Mapper<I, O> mapper, Collection<I> input) {
        requireNonNull(mapper, "mapper cannot be null");

        if (input == null) {
            return null;
        }

        return input.stream()
                .map(mapper::map)
                .collect(toList());
    }

    private  MapperUtils();

}