DomainObjectsDataMapper works only for value objects

[Nek-]

DomainObjectsDataMapper is used as default data mapper but works only for value objects. It may be a good idea to verify if the current objet is not a value object and keep the old object in this case.

    public function mapFormsToData($forms, &$data)
    {
        if ($data instanceof CrudableModelInterface) {
            return $data;
        }
        $data = $this->createObject($forms, !empty($data) && is_object($data) ? get_class($data) : null);
        parent::mapFormsToData($forms, $data);
    }

Maybe this piece of code is a good idea. I'm not sure it's actually is but well. We need to think about.

In any case, considering the option "customDataMapper", there's no problem that the default datamapper does not support every case.