ZF2 Doctrine Flush Listener

FlushEntities.php

<?php

namespace Application\Listener\Doctrine;

use Doctrine\DBAL\DBALException;
use Doctrine\ORM\EntityManager;
use Zend\EventManager\EventInterface;
use Zend\Mvc\MvcEvent;

class FlushEntities
{
    public static $requiresFlush = false;

    const ERROR_FLUSH = 'error-flush';


    public static function flush(EventInterface $e)
    {
        if ($e->getParam('delay') == true) {
            self::$requiresFlush = true;
            return;
        }

        if ($e->getTarget() instanceof EntityManager) {
            $em = $e->getTarget();
            if (self::$requiresFlush) {
                $em->flush();
                self::$requiresFlush = false;
            } else {
                $em->flush($e->getParam('entity'));
            }
            return;
        }

        if (!self::$requiresFlush) {
            return;
        }

        if (!$e instanceof MvcEvent) {
            return;
        }

        try {
            $e->getApplication()->getServiceManager()->get('EntityManager')->flush();
            self::$requiresFlush = false;
        } catch (DBALException $ex) {
            $e->setError(self::ERROR_FLUSH)
              ->setParam('exception', $ex);
            $e->getApplication()->getEventManager()->trigger(MvcEvent::EVENT_DISPATCH_ERROR, $e);
        }
    }
}

To use this, attach like so;

$app->getEventManager()->attach(MvcEvent::EVENT_DISPATCH, array('Application\Listener\Doctrine\FlushEntities', 'flush'), -1);

and

$events->attach(__NAMESPACE__, 'flush', array('Application\Listener\Doctrine\FlushEntities', 'flush'));

Any thoughts, improvements?