public function getCacheControl()
    {
        $values = $this->_headers->get('Cache-Control', array());

        if (is_string($values)) {
            $values = explode(',', $values);
        }

        foreach ($values as $key => $value)
        {
            if(is_string($value))
            {
                $parts = explode('=', $value);

                if (count($parts) > 1)
                {
                    unset($values[$key]);
                    $values[trim($parts[0])] = trim($parts[1]);
                }
            }
        }

        return $values;
    }