public function __construct($settings = [])
{
// check Memcached extension
if (!extension_loaded('memcached')) {
throw new ComponentException("Memcached extension not installed/enabled.\n Install and/or enable memcached extension. See phpinfo() for more information");
}
// check Memcached settings
if (!is_array($settings) || empty($settings) || !isset($settings['servers'])) {
throw new ConfigurationException("Memcached configuration is missed. Please check 'cache' configuration section");
}
parent::__construct($settings);
}