public function validate($value, Constraint $constraint)
{
try {
// The email is already in our mailing list
if ($this->subscriber->isSubscribed($value)) {
$this->context->buildViolation($constraint->alreadySubscribedMessage)->addViolation();
}
// fallback for when no mail-engine is chosen in the Backend
} catch (NotImplementedException $e) {
// do nothing
}
}