ZF2 SM, Do I really need to - zend-framework2

Question

I currently have a ZF2 Module which needs access to three database tables. No other module needs access to these tables.
So my question is (performance in mind too, please) should I really add the factories to the Module.php like I have been doing:
/**
* Service Configuration
*
* #return array
*/
public function getServiceConfig()
{
return array(
'invokables' => array(
'Login\Service\Authenticate' => 'Login\Service\Authenticate',
'Login\Service\Oauth' => 'Login\Service\Oauth'
),
'factories' => array(
'Login\Form\Login' => function () {
$form = new Form\Login();
$form->setInputFilter(new FormFilter\Login());
return $form;
},
'Login\Model\GaclEmployeePermission' => function ($sm) {
return new Model\GaclEmployeePermission($sm->get('OTWebsoft\Db\Adapter\Master'), $sm->get('OTWebsoft\Db\Adapter\Slave'));
},
'Login\Model\Passport' => function ($sm) {
return new Model\Passport($sm->get('OTWebsoft\Db\Adapter\Master'), $sm->get('OTWebsoft\Db\Adapter\Slave'));
},
'Login\Model\PassportLog' => function ($sm) {
return new Model\PassportLog($sm->get('OTWebsoft\Db\Adapter\Master'), $sm->get('OTWebsoft\Db\Adapter\Slave'));
}
)
);
}
Then I have an abstract class which does:
/**
* Table GaclEmployeePermission
*
* #return \Login\Model\GaclEmployeePermission
*/
protected function getTableGaclEmployeePermission()
{
return $this->getServiceManager()->get('Login\Model\GaclEmployeePermission');
}
OR should I just remove the configuration from the Module.php and in my abstract class just do this:
/**
* Table GaclEmployeePermission
*
* #return \Login\Model\GaclEmployeePermission
*/
protected function getTableGaclEmployeePermission()
{
return new GaclEmployeePermission($this->getMasterAdapter(), $this->getSlaveAdapter());
}
Both seems to work exactly the same. But when it comes to performance, which would you recommend? Keeping in mind, these three tables do not need to be accessed from any other module but this one.

Answer 1

The main reason to use a service manager or dependency injection container is not that other services could access it. The main reason is to apply dependency injection and thereby you apply inversion of control. This ease the usage of your objects, allow you to swap implementations easily, enhance the ability to test the class and to keep the class responsible about the contained logic and not bothering its dependencies.
In both examples, you actually use the service manager but it's still the same pattern: the class (inside getTableGaclEmployeePermission()) decides what to get. Either via the service manager or via direct instantiation, that does not actually matter much.
By your module configuration I cannot grasp the layers you have in the application and what they do (esp. what's about that abstract class), but in general, you should inject it's dependencies:
abstract class SomeAbstract
{
protected $permission;
public function __construct(Permission $permission)
{
$this->permission = $permission;
}
}
class Permission
{
protected $master;
protected $slave;
public function __construct(TableAdapter $master, TableAdapter $slave = null)
{
$this->master = $master;
if (null !== $slave) {
$this->slave = $slave;
}
}
}
Then you create the service manager configuration to inject those dependencies for the services you define:
'factories' => array(
'Login\Model\Permission' => function ($sl) {
$master = $sl->get('My\MasterAdapter');
$slave = null;
if ($some_flag) {
$slave = $sl->get('My\SlaveAdapter');
}
return new Login\Model\Permission($master, $slave);
},
'Login\Some\ConcreteImplementation' => function ($sl) {
$permission = $sl->get('Login\Model\Permission');
return new Login\Some\ConcreteImplementation($permission);
}
),
Then you request Login\Some\ConcreteImplementation and all the injection ($master, $slave and $permission) is done for you, enabling all the benefits described above.