class ProductCartDao extends HibernateDao<ProductCart, String> {

   public List<Product> scrollCartOfUser(final User user, final int skip, final int top)
   {
      if (user == null)
      {
         return Collections.emptyList();
      }
      ProductCart cart = getCartOfUser(user);
      if (cart == null)
      {
         return Collections.emptyList();
      }

      return setToLimitedList(cart.getProducts(), skip, top);
   }

}