protected function validateCombinationPriceProduct($index, &$combination)
    {
        $price = $this->getSubmitted('price');

        if (empty($combination['price'])) {
            $combination['price'] = $price;
        }

        if (!is_numeric($combination['price']) || strlen($combination['price']) > 10) {
            $error = $this->translation->text('Only numeric values and no longer than @num characters', array('@num' => 10));
            $this->setError("combination.$index.price", $error);
        }

        return !isset($error);
    }