protected function setHashData()
    {
        foreach ($this->hashFields as $field) {
            $params = $this->validFields[$field];
            if ($params['type'] == "single") {
                if (isset($this->fieldData[$field])) {
                    $this->hashData[] = $this->fieldData[$field];
                }
            } elseif ($params['type'] == "product") {
                foreach ($this->products as $product) {
                    if (isset($product[$params["paramName"]])) {
                        $this->hashData[] = $product[$params["paramName"]];
                    }
                }
            }
        }
    }