public function submitCart($cart_action_model)
    {
        $this->setSubmitted('product');
        $this->filterSubmitted(array('product_id'));

        if ($this->isPosted('add_to_cart')) {
            $this->validateAddToCart();
            $this->addToCart($cart_action_model);
        } else if ($this->isPosted('remove_from_cart')) {
            $this->setSubmitted('cart');
            $this->deleteFromCart($cart_action_model);
        }
    }