aggregateId() абстрактный защищенный Метод

abstract protected aggregateId ( ) : string
Результат string representation of the unique identifier of the aggregate root
 /**
  * @param AggregateRoot $anAggregateRoot
  * @return string
  */
 public function extractAggregateId(AggregateRoot $anAggregateRoot)
 {
     return $anAggregateRoot->aggregateId();
 }