gistfile1.php

<?php

class YourDomainClass
{
    protected $manager;

    public function __construct(PersistenceManager $manager)
    {
        $this->manager = $manager;
    }
    
    public function doSomething()
    {
        $entity = new Entity();
        
        // do something
        
        $this->manager->persist($entity);
    }
}

interface PersistenceManager
{
    function persist($entity);
}

class DoctrineManager implements PersistenceManager
{
    protected $em;

    public function __construct(EntityManager $em)
    {
        $this->em = $em;
    }

    public function persist($entity)
    {
        $this->em->persist($entity);
        $this->flush();
    }
}