static Val[] emptyArray() {
        return EMPTY_VALUES;
    }
@param isCaseSensitive Set to false for a case-insensitive comparator.
                       Some impls may ignore this parameter, e.g. numeric {@link Val}
                       impls.
@return A comparator that will compare {@link Val} instances using the
comparison method of the subclass in question. Only intended for use on
{@link Val} instances of the same class. To compare {@link Val} instances
of potentially mixed types in a null-safe way, see
{@link ValComparators#getComparator(boolean)}.
stroom-query/stroom-query-language/src/main/java/stroom/query/language/functions/Val.java