Syntax
// src/Entity/UserSettings.php
namespace App\Entity;
use Symfony\Component\Validator\Constraints as Assert;
class UserSettings
{
/**
* @Assert\Timezone
*/
protected $timezone;
}// Consider valid only the timezones from countries in America continent
/** @Assert\Timezone(zone=\DateTimeZone::AMERICA) */
protected $timezone;
// Consider valid only the Chinese timezones
/** @Assert\Timezone(zone=\DateTimeZone::PER_COUNTRY, countryCode="CN") */
protected $timezone;