Flow2Lab/EventSourcing

<?php
namespace Flow2Lab\EventSourcing;

use Flow2Lab\EventSourcing\Event\DomainEvent;

trait EntitySourcing
{

    use EventSourcing {
        apply as public;
    }

    /**
     * @var AggregateRootInterface
     */
    protected $aggregateRoot;

    /**
     * @var \Closure
     */
    protected $versionGenerator;

    /**
     * @param AggregateRootInterface $aggregateRoot
     * @return void
     */
    public function setAggregateRoot(AggregateRootInterface $aggregateRoot)
    {
        $this->aggregateRoot = $aggregateRoot;
    }

    /**
     * @param \Closure $getNextVersion
     * @return void
     */
    public function setVersionGenerator(\Closure $getNextVersion)
    {
        $this->versionGenerator = $getNextVersion;
    }

    /**
     * @param DomainEvent $event
     */
    protected function applyNewEvent(DomainEvent $event)
    {
        $event->version = $this->getNextVersion();

        $this->apply($event);
        $this->uncommittedEvents[] = $event;
    }

    /**
     * @param EntityInterface $entity
     */
    protected function registerEntity(EntityInterface $entity)
    {
        $entityIdentifier = $entity->getIdentifier();

        if (array_key_exists($entityIdentifier, $this->entities) === TRUE) {
            throw new \InvalidArgumentException('The entity with identifier "' . $entityIdentifier . '" is already registered.', 1426251092);
        }

        $entity->setAggregateRoot($this->aggregateRoot);
        $entity->setVersionGenerator($this->versionGenerator);

        $this->entities[$entityIdentifier] = $entity;
    }

    /**
     * @return integer
     */
    protected function getNextVersion()
    {
        $versionGenerator = $this->versionGenerator;
        return $versionGenerator();
    }

}