public static int compare(final Value v1, final Value v2) {
        if (v1 == v2) {
            return 0;
        }
        if (v1 == null || v2 == null) {
            return v1 == null ? -1 : 1;
        }
        return v1.compareTo(v2);
    }
Encapsulates a single value for handling in {@link Formula}. Provides e.g. type conversions.
<br>
Supports raw values of type String, CharSequence, Double, Long, BigInterger and BigDecimal
main/src/main/java/cgeo/geocaching/utils/formulas/Value.java