Dependency Injection. It Works This Way But Something Tells Me I'm Doing It Wrong.

[david91]

In the application I am coding myself (MVC) I am using dependency injection to pass an object its dependencies. I don't want to use the Singleton pattern or a dependency injection container.

 

When the application starts up it has some procedural code instantiating important objects like this: (It loads up more objects than below but they should be enough to explain what I am on about)

 

/*
* ------------------------------------------------------
* INSTANTIATE THE APPLICATION CLASS
* ------------------------------------------------------
*/
$app = new App();
$app->environment('development');


/*
* ------------------------------------------------------
* INSTANTIATE THE CONFIGURATION CLASS
* ------------------------------------------------------
*/
$config = new Config();


/*
* ------------------------------------------------------
* INSTANTIATE THE LOGGER CLASS
* ------------------------------------------------------
*/
$logger = new Logger($config);


/*
* ------------------------------------------------------
* INSTANTIATE THE LOCALE CLASS
* ------------------------------------------------------
*/
$locale = new Locale();


/*
* ------------------------------------------------------
* INSTANTIATE THE HTTP RESPONSE CLASS
* ------------------------------------------------------
*/
$httpResponse = new HttpResponse();


/*
* ------------------------------------------------------
* INSTANTIATE THE ROUTER CLASS
* ------------------------------------------------------
*/
$router = new Router($config, $logger, $httpResponse);
$router->route();

 

As you can see the $logger object depends on the $config object and I inject the $config object into the $logger objects constructor.

 

Now, as you can see when I am instantiating the $router object it has 3 dependencies ($config, $logger and $httpResponse).

 

I just feel it's weird how the $logger object holds the $config object within it so anywhere I inject the $config object and the $logger object into an object like in the $router object I feel like I'm injecting the $config object twice and that it's wrong.

 

Obiously when I have more and more objects and dependencies it will seem like I am injecting the same object more than two or three times and that will really make me wonder if I'm doing it wrong.

 

Is what I'm doing ok?

 

Thanks.

[ignace]

Is what I'm doing ok?

 

Sure, you are only passing references any way not entire objects.