MuZ - Derived Property example

SetDerivedPropertyEventSubscriber.php

<?php

namespace Muz\Beesite\Backend\DataStorage\EventListener;

use Doctrine\Common\EventSubscriber;
use Doctrine\ORM\Event\OnFlushEventArgs;
use Doctrine\ORM\Events;

/**
 * @see http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/events.html#implementing-event-listeners
 * 
 * To subscriber has to be registered at application bootstrap like this:
 * 
 * $entityManager = $serviceManager->get(EntityManager::class);
 * $entityManager->getEventManager()->addEventSubscriber(new SetDerivedPropertyEventSubscriber());
 */
class SetDerivedPropertyEventSubscriber implements EventSubscriber
{
    public function getSubscribedEvents()
    {
        return [
            Events::onFlush,
        ];
    }

    public function onFlush(OnFlushEventArgs $args)
    {
        $em = $args->getEntityManager();
        $uow = $em->getUnitOfWork();

        $deletedObjectIds = array_filter(array_map(function($object) {

            if ($object instanceof \Muz\Entity\Test2)
            {
                return $object->getId();
            }

            return null;

        }, $uow->getScheduledEntityDeletions()));

        $changeSet = array_merge(
            $uow->getScheduledEntityInsertions(),
            $uow->getScheduledEntityUpdates(),
            $uow->getScheduledEntityDeletions()
        );
        foreach ($changeSet as $object)
        {
            if (!($object instanceof \Muz\Entity\Test2) || !$object->getTest())
            {
                continue;
            }

            /** @var \Muz\Entity\Test2 $object */

            // only consider related objects not scheduled for deletion
            $relatedObjects = array_filter($object->getTest()->getTest2(), function(\Muz\Entity\Test2 $relatedObject) use ($deletedObjectIds) {

                return !in_array($relatedObject->getId(), $deletedObjectIds);
            });

            // update derived property
            $object->getTest()->setDerived(implode(' ', array_map(function(\Muz\Entity\Test2 $test2) { return $test2->getX(); }, $relatedObjects)));

            // doctrine has to be informed about an updated property of a related object
            $uow->recomputeSingleEntityChangeSet($em->getClassMetadata(\Muz\Entity\Test::class), $object->getTest());
        }
    }
}