Domain-Driven Design in PHP

Extra Behavior

interface PostRepository {      // ...     public function size(); }

The implementation could look like this:

class DoctrinePostRepository implements PostRepository{    // ...    public function size()    {        return $this->em->createQueryBuilder()            ->select('count(p.id)')            ->from('Domain\Model\Post', 'p')            ->getQuery()            ->getSingleScalarResult();    }} 

Adding additional behavior to a Repository can be very beneficial. An example of this is the ability to count all the items in a given collection. You might think to add a method with the name count; however, as we're trying to mimic a collection, a better name would instead be size:

You're also able to place specific calculations, counters, read-optimized queries, or complex commands (INSERT,