Flow2Lab/EventSourcing

<?php
namespace Flow2Lab\EventSourcing\Projection;

use Flow2Lab\EventSourcing\Event\DomainEvent;
use TYPO3\Flow\Annotations as Flow;
use TYPO3\Flow\Persistence\PersistenceManagerInterface;
use TYPO3\Flow\Persistence\QueryInterface;

/**
 * @Flow\Scope("singleton")
 */
abstract class AbstractModelProjector extends AbstractProjector
{

    /**
     * @var PersistenceManagerInterface
     * @Flow\Inject
     */
    protected $persistenceManager;

    /**
     * @param DomainEvent $event
     * @throws \Flow2Lab\EventSourcing\Event\Handler\Exception\UnableToHandleEventException
     */
    public function handle(DomainEvent $event)
    {
        parent::handle($event);
        $this->persistenceManager->persistAll();
    }

    /**
     * Clears and rebuilds the projection persistence structure
     *
     * @return void
     */
    public function build()
    {
        foreach ($this->findAll() AS $object) {
            $this->deleteById(
                $this->persistenceManager->getIdentifierByObject($object)
            );
        }
    }

    /**
     * @param string $identifier
     * @return NULL|object
     */
    public function findById($identifier)
    {
        return $this->persistenceManager->getObjectByIdentifier($identifier, $this->projectionClassName);
    }

    /**
     * @return object[]
     */
    public function findAll()
    {
        return $this->createQuery()
            ->execute()
            ->toArray();
    }

    /**
     * @return integer
     */
    public function countAll()
    {
        return $this->createQuery()
            ->count();
    }

    /**
     * @param string $identifier
     */
    public function deleteById($identifier)
    {
        $object = $this->findById($identifier);

        // todo: check if we want to throw an exception here
        if ($object !== NULL) {
            $this->persistenceManager->remove($object);
            $this->persistenceManager->persistAll();
        }
    }

    /**
     * @return QueryInterface
     */
    protected function createQuery()
    {
        return $this->persistenceManager->createQueryForType($this->projectionClassName);
    }

}