protected function getConfigOption(array $config, $key)
    {
        if (empty($config[$key]) || !is_string($config[$key])) {
            throw new \DomainException(
                "$key must be a non-empty string"
            );
        }
        return $config[$key];
    }
protected function getConfigOption(array $config, $key)
    {
        if (empty($config[$key]) || !is_string($config[$key])) {
            throw new \DomainException(
                "$key must be a non-empty string"
            );
        }
        return $config[$key];
    }
protected function getConfigOption ( array $ config , $ key ) { if ( empty ( $ config [ $ key ] ) || ! is_string ( $ config [ $ key ] ) ) { throw new \ DomainException ( "$key must be a non-empty string" ) ; } return $ config [ $ key ] ; }
Extracts a string from the config options map.

@param array $config
@param string $key
@return string
@throws \DomainException if password is unspecified or not a string
Extracts a string from the config options map .