Sequence per entity for doctrine with pessimistic lock

BusinessTransactionHandler.php

<?php

class BusinessTransactionHandler{
  	public function persistOrder( Order $order, EntityManager $em ) {
		$em->beginTransaction();
		try {
			$counter = $em->find( "AppBundle:ShopOrderCounter",
			                      $order->getShop()
			                            ->getOrderCounter()
			                            ->getId(),
			                      LockMode::PESSIMISTIC_WRITE );
		} catch ( OptimisticLockException $e ) {
			throw new HandlerException( "Ошибка блокировки", $e );
		} catch ( TransactionRequiredException $e ) {
			throw new HandlerException( "Ошибка блокировки", $e );
		} catch ( ORMException $e ) {
			throw new HandlerException( "Ошибка блокировки", $e );
		}
		
		$order->setNumber( $counter->nextNumber() );
		
		$em->persist( $order );
		
		try {
			$em->flush();
			$em->commit();
		} /** @noinspection PhpRedundantCatchClauseInspection */ catch ( UniqueConstraintViolationException $unique ) {
			$em->rollback();
			throw new ConflictHttpException( "Такой заказ уже существует", $unique );
		} catch ( \Exception $exception ) {
			$em->rollback();
			throw new BadRequestHttpException( "Ошибка сервера при записи данных заказа", $exception );
		}
	}
}

Shop.php

<?php

namespace AppBundle\Entity;

use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;
use Doctrine\ORM\Mapping as ORM;

/**
 * Shop
 *
 * @ORM\Table(name="shop")
 * @ORM\Entity(repositoryClass="AppBundle\Repository\ShopRepository")
 */
class Shop {
	/**
	 * @var int
	 *
	 * @ORM\Column(name="id", type="integer")
	 * @ORM\Id
	 * @ORM\GeneratedValue(strategy="IDENTITY")
	 */
	private $id;
	/**
	 * @var ArrayCollection
	 * @ORM\OneToMany(targetEntity="AppBundle\Entity\Order", mappedBy="shop")
	 */
	private $orders;
	/**
	 * @var ShopOrderCounter
	 * @ORM\OneToOne(targetEntity="ShopOrderCounter", cascade={"all"})
	 * @ORM\JoinColumn(name="order_counter", referencedColumnName="id")
	 */
	protected $orderCounter;
	
	/**
	 * @return ShopOrderCounter
	 */
	public function getOrderCounter() {
		return $this->orderCounter;
	}
	
	/**
	 * Shop constructor.
	 */
	public function __construct() {
		$this->orders       = new ArrayCollection();
		$this->orderCounter = new ShopOrderCounter();
	}

	/**
	 * @return int
	 */
	public function getId() {
		return $this->id;
	}
	
	public function registerOrder( Order $order ) {
		if ( ! $this->orders->contains( $order ) ) {
			$this->orders->add( $order );
		}
	}
}

ShopOrderCounter.php

<?php

namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * ShopNumber
 *
 * @ORM\Table(name="shop_order_counter")
 * @ORM\Entity(repositoryClass="AppBundle\Repository\ShopOrderCounterRepository")
 */
class ShopOrderCounter {
	/**
	 * @var int
	 *
	 * @ORM\Column(name="id", type="integer")
	 * @ORM\Id
	 * @ORM\GeneratedValue(strategy="IDENTITY")
	 */
	protected $id;
	/**
	 * @var int следующий свободный номер заказа
	 * @ORM\Column(name="next_order_number", type="integer")
	 */
	protected $nextOrderNumber;
	
	/**
	 * ShopNumber constructor.
	 *
	 * @param int $nextOrderNumber
	 */
	public function __construct() {
		$this->nextOrderNumber = 1;
	}
	
	/**
	 * Get id
	 *
	 * @return int
	 */
	public function getId() {
		return $this->id;
	}
	
	/**
	 * @return int
	 */
	public function nextNumber() {
		$next                  = $this->nextOrderNumber;
		$this->nextOrderNumber = $next + 1;
		return $next;
	}

}