class JsonCharEscaper implements Function<Integer, String> {

    @Nullable
    @Override
    public String apply(final Integer i) {
        if (0 <= i && i < ESCAPE_TABLE.length) {
            return ESCAPE_TABLE[i];
        } else {
            // return null for higher characters which are valid unescaped.
            return null;
        }
    }

    private  JsonCharEscaper();

}