class TypeValidator {

    public static boolean isSupportedForJoin(TInstance type1, TInstance type2) {
        TClass tclass1 = TInstance.tClass(type1);
        TClass tclass2 = TInstance.tClass(type2);
        return ((tclass1 != null) && (tclass2 != null) &&
                isSupportedForJoin(tclass1, tclass2));
    }

    private  TypeValidator();

}