"usort" a Doctrine\Common\Collections\ArrayCollection?

To sort an existing Collection you are looking for the ArrayCollection::getIterator() method which returns an ArrayIterator. example:

$iterator = $collection->getIterator();
$iterator->uasort(function ($a, $b) {
    return ($a->getPropery() < $b->getProperty()) ? -1 : 1;
});
$collection = new ArrayCollection(iterator_to_array($iterator));

The easiest way would be letting the query in the repository handle your sorting.

Imagine you have a SuperEntity with a ManyToMany relationship with Category entities.

Then for instance creating a repository method like this:

// Vendor/YourBundle/Entity/SuperEntityRepository.php

public function findByCategoryAndOrderByName($category)
{
    return $this->createQueryBuilder('e')
        ->where('e.category = :category')
        ->setParameter('category', $category)
        ->orderBy('e.name', 'ASC')
        ->getQuery()
        ->getResult()
    ;
}

... makes sorting pretty easy.

Hope that helps.

Since Doctrine 2.3 you can use the Criteria API

Eg:

<?php

public function getSortedComments()
{
    $criteria = Criteria::create()
      ->orderBy(array("created_at" => Criteria::ASC));

    return $this->comments->matching($criteria);
}

Note: this solution requires public access to $createdAt property or a public getter method getCreatedAt().