symfony: Validating form field, many-to-many-relationship - forms

Question

I have three entities: User, Work and Journal. There is a many-to-many-relationship between User and Work defined as follows:
In the Work entity:
/**
* #ORM\ManyToMany(targetEntity="User", inversedBy="peerReviewedWorks")
* #ORM\JoinTable(name="test_work_user_peer")
*/
private $peerReviewers
In the User entity:
/**
* #ORM\ManyToMany(targetEntity="Work", mappedBy="peerReviewers")
*/
private $peerReviewedWorks;
There is no relationship between my third entity, Journal, and User but a one-to-many-relationship between Journal and Work:
Journal entity:
/**
* #ORM\OneToMany(targetEntity="Work", mappedBy="journal")
*/
private $works;
Work entity:
/**
* #ORM\ManyToOne(targetEntity="Journal", inversedBy="works")
* #ORM\JoinColumn(name="journal_id", referencedColumnName="id")
*/
private $journal;
From the Work controller I am creating a form which lets the editor choose the peer-reviewers from a list and assign them to a work:
<?php
public function manageAction(Request $request, Work $work)
{
// ...
$form = $this->createForm(ManageWorkType::class, $work);
$form->handleRequest($request);
if ($form->isSubmitted() && $form->isValid()) {
// ...
}
}
The ManageWorkType class looks as follows:
<?php
class ManageWorkType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder
// add some stuff
->add('submit', SubmitType::class)
;
$builder->addEventListener(FormEvents::PRE_SET_DATA, function (FormEvent $event) {
$work = $event->getData();
$form = $event->getForm();
// form field only added when journal is peer-reviewed
if($work->getJournal()->getIsPeerReviewed() == 1) {
// get a list of all active peer-reviewers
$form->add('peerReviewers', EntityType::class, array(
'class' => 'PlatformBundle:User',
'query_builder' => function (EntityRepository $er) {
return $er->createQueryBuilder('u')
->where('u.peerReviewStatus = :status')
->setParameter('status', 'active')
;
},
'multiple' => true,
));
}
});
// ...
}
Since not every journal requires the same number of peer-reviews, I have a field number_of_peer_reviewers in the Journal entity which holds the number of required peer-reviewers:
Journal entity:
/**
* #var string
*
* #ORM\Column(name="numberOfPeerReviewers", type="string", length=1, nullable=true)
*/
private $numberOfPeerReviewers;
Before assigning the peer-reviewers from the User entity to the Work entity I have to check if the editor who submitted the form selected the required number of peer-reviewers from the list. If this is not the case the form should not be valid.
In order to achieve this I tried to use a callback validator in the Work entity but failed miserably:
/**
* #ORM\ManyToMany(targetEntity="User", inversedBy="peer_reviewed_works")
* #ORM\JoinTable(name="test_work_user_peer")
* #Assert\Valid
*/
private $peerReviewers;
// ...
/**
* #Assert\Callback
*/
public function validate(ExecutionContextInterface $context, $payload)
{
if(count($this->getPeerReviewers()) < $this->getPeerReviewers()->getNumberOfPeerReviewers()) {
$context->buildViolation('Error message')
->atPath('peerReviewers')
->addViolation();
}
}
As you can see I do not know how to access the number_of_peer_reviewers field from the Journal table.
Any guidance is greatly appreciated.