Zend Framework 2: get the ServiceManager in an Entity

Album.php

<?php

namespace Album\Model;

use Zend\ServiceManager\ServiceManager;
use Zend\ServiceManager\ServiceManagerAwareInterface;

class Album implements ServiceManagerAwareInterface
{
    protected $serviceManager;

    //...

    public function getSongs()
    {
        return $this->getServiceManager()
                    ->get('Album\Model\SongsTable')
                    ->getSongsByAlbumId($this->getId());
    }

    public function setServiceManager(ServiceManager $serviceManager)
    {
        $this->serviceManager = $serviceManager;

        return $this;
    }

    public function getServiceManager()
    {
        return $this->serviceManager;
    }
}

AlbumsTable.php

<?php

namespace Album\Model;

use Zend\ServiceManager\ServiceManager;
use Zend\ServiceManager\ServiceManagerAwareInterface;

class AlbumsTable extends AbstractTableGateway
{
    protected $serviceManager;

    public function __construct(Adapter $adapter, ServiceManager $serviceManager)
    {
        $this->serviceManager = $serviceManager;
        $this->adapter = $adapter;
        $this->resultSetPrototype = new ResultSet();
        //$this->resultSetPrototype->setArrayObjectPrototype(new Album());
        $this->resultSetPrototype->setArrayObjectPrototype(
            $this->serviceManager->get('Album\Model\Album')
        );
        $this->initialize();
    }

    //...
}

Module.php

    public function getServiceConfig()
    {
        return array(
            'factories' => array(
                'Album\Model\AlbumsTable' =>  function($sm) {
                    $dbAdapter = $sm->get('Zend\Db\Adapter\Adapter');
                    $table = new AlbumsTable($dbAdapter, $sm);
                    return $table;
                },
                'Album\Model\Album' =>  function($sm) {
                    return new Model\Album();
                },
            ),
        );
    }