Symfony2 Best practices - sorting of entities - model-view-controller

Question

I am creating an application in Symfony2. This is the first time I develop using a framework and one of my first projects. It is a student project.
In this project, I want my collections of entities to be sorted somewhere before reaching the view. This can be done in this way:
In getters on the entities on the many-to-one relations, with comparator methods on the many-side that is used by the usort() method in the getter on the one-side. Below I have a method that also fills in gaps in a collection of "Day" entities (in a form of diary), but the point is that it sorts the days with usort.
In User entity class:
public function getDaysWithNulls()
{
$days = $this->getDays()->toArray();
//get the first day and find out how many days have passed
usort($days, array("\Pan100\MoodLogBundle\Entity\Day", "daySorter"));
$firstEntry = $days[0];
$interval = $firstEntry->getDate()->diff(new \DateTime());
$numberOfDaysBack = $interval->d;
//create an array consisting of the number of days back
$daysToShow = array();
for ($i=0; $i < $numberOfDaysBack ; $i++) {
$date = new \DateTime();
$date->sub(new \DateInterval('P' . $i . 'D'));
$daysToShow[] = $date;
}
$daysToReturn = array();
foreach ($daysToShow as $day) {
//figure out if this day has an entity, if not set an empty Day object
$dayEntityToProcess = new \Pan100\MoodLogBundle\Entity\Day();
$dayEntityToProcess->setDate($day);
foreach ($days as $dayEntity) {
//check if there is a day entity
if($day->format('Y-m-d') == $dayEntity->getDate()->format('Y-m-d')) {
$dayEntityToProcess = $dayEntity;
}
}
$daysToReturn[] = $dayEntityToProcess;
}
//return a collection
return new \Doctrine\Common\Collections\ArrayCollection($daysToReturn);
}
usort uses this in the Day entity class:
static function daySorter($dayEntity1, $dayEntity2) {
$interval = $dayEntity1->getDate()->diff($dayEntity2->getDate());
if($interval->invert == 1) {
return +1;
}
else if ($interval->invert == 0) {
return 0;
}
else return -1;
}
My question is: is this the best practice for sorting and returning sorted collections, or should sorting happen somewhere else?

Answer 1

I did think this was a tedoius way of doing it. So I searched the web a bit, and read some more, and found that I can create custom repositories.
I will do it this way instead:
http://symfony.com/doc/2.1/book/doctrine.html#custom-repository-classes
EDIT: found out the sorting is better done in annotations:
/**
* #ORM\OneToMany(targetEntity="Day", mappedBy="user_id")
* #ORM\OrderBy({"date" = "DESC"})
**/
protected $days;