New method saveOrUpdateTopSubs

[XinYang-Pan]

public <P, C> void saveOrUpdateTopSubs(P top, List<C> subs, Supplier<C> exampleSupplier, Function<P, Long> topIdGetter, Function<C, Long> subIdGetter) {
    // save or update top
    super.saveOrUpdate(top);
    if (CollectionUtils.isEmpty(subs)) {
        return;
    }
    // delete subs
    List<C> existingChilds = this.findByExample(exampleSupplier.get());
    Map<Long, C> existingChildMap = UtilHelper.mapUniqueValue(existingChilds, subIdGetter);
    for (C c : subs) {
        Long id = subIdGetter.apply(c);
        if (id != null) {
            existingChildMap.remove(id);
        }
    }
    // 
    for (C c : existingChildMap.values()) {
        this.delete(c);
    }
    // save or update subs
    for (C c : subs) {
        this.saveOrUpdate(c);
    }
}