Array Collection persistence on symfony2 - symfony

Question

i'm using a event listener on the submit of a form where, i need to catch a xml file, open it and extract his contents, put it on an entity and add that to a collection from other entity.
right now this is works:
$builder->addEventListener(FormEvents::SUBMIT, function(FormEvent $event){
$entity = $event->getData();
if($entity){
$parent = $event->getForm()->getParent()->getData();
$gpx = $entity['gpx'];
if($gpx){
$xmlGpx = simplexml_load_file($gpx);
foreach ($xmlGpx->wpt as $pt) {
$point = new MonitoringPoint();
$point->setPoint(new \CrEOF\Spatial\PHP\Types\Geometry\Point((string) $pt['lat'], (string) $pt['lon']));
$point->setAltitude((float) $pt->ele);
$point->setDate(($pt->time->count() ? new \DateTime((string)$pt->time) : null ));
$point->setAccuracy((float) $pt->hdop);
$parent->addMonitoringPoint($point);
}
$fileName = $gpx->getClientOriginalName();
$directory = __DIR__.'/../../../../web/uploads/';
$date = new \DateTime();
$newFileName = md5($gpx->getClientOriginalName().$date->getTimestamp());
$gpx->move($directory, $fileName);
$fs = new Filesystem();
$fs->rename($directory.$fileName, $directory.$newFileName.'.gpx');
$parent->setGpx($newFileName.'.gpx');
}
}
});
$parent is an instance of Monitoring, if i open $parent i will see that the $point vars has been added on the collection monitoringPoints of the variable, and the gpx too.
but then i go so see the entity right before been persisted, inside newAction
$entity = new Monitoring($params);
$form = $this->createForm(new MonitoringType(), $entity, array(
'action' => $this->generateUrl('my_route'),
'method' => 'POST',
));
$form->handleRequest($request);
if ($form->isSubmitted() && $form->isValid()) {
dump($entity);die;
$em = $this->getDoctrine()->getManager();
$em->persist($entity);
$em->flush();
}
and the collection is empty! but the gpx attribute contains the right value.
does the collection gets reseted?

Answer 1

i had to pass the points in to an array within the session, still think that was not the best option, but worked
$array = [];
foreach ($xmlGpx->wpt as $pt) {
$point = new MonitoringPoint();
$point->setPoint(new \CrEOF\Spatial\PHP\Types\Geometry\Point((string) $pt['lat'], (string) $pt['lon']));
$point->setAltitude((float) $pt->ele);
$point->setDate(($pt->time->count() ? new \DateTime((string)$pt->time) : null ));
$point->setAccuracy((float) $pt->hdop);
$point->setMonitoring($parent);
array_push($array, $point);
}
$session = new Session();
$session->getFlashBag()->add('array', $array);
in the newAction:
$em = $this->getDoctrine()->getManager();
$session = new Session();
$array = $session->getFlashBag()->get('array');
foreach($array[0] as $point) {
$point->setMonitoring($entity);
$entity->addMonitoringPoint($point);
}
$em->persist($entity);
$em->flush();
dont know why the array got reseted when it comes to the controller, cause i had setted the points in the entity during the submit