}

    @Nullable
    public <T> T findByType(TypeOf<T> type) {
        ExtensionHolder<T> found = findHolderByType(type);
        return found != null ? found.get() : null;
    }

    private <T> ExtensionHolder<T> getHolderByType(TypeOf<T> type) {
        ExtensionHolder<T> found = findHolderByType(type);
        if (found != null) {
            return found;
        }
        throw new UnknownDomainObjectException(