Question

In a application that use Repositories and Services pattern, how to make sure Service layer is always called and not the Repositories directly ?

Example :

class OrderRepository
{
    void CreateOrder(Order o)
    ...
}

class OrderService
{
    void CreateOrder(Order o)
    {
        //make some business logic tests
        ... 

        //call repository
        _orderRepository.CreateOrder(o);
    }
}

I see two issues :

• A programmer may call the repository directly because it doesn’t know the existance of a service (sometimes its not as simple as in this example (1 service = 1 repository with same method names). some applications are not very well documented. or someone in hurry can forget to check if corresponding service exists (mistake)).

• Totally different : long time ago someone created some views + controllers that use order repository directly. At that time there was no need to have some business logic check or additional operations, only order repository exists (because there it was not needed at all). If later, some additional operations when creating an order would be needed, a service will be created. the problem is that all controllers that make old repositories calls will need to be changed. Isn’t repository principle/idea (and separating code in layers) supposed to make parts independent from each other ?

Answer 1

You can structure your solution so that all repositories and services are in their own respective projects, ex. Repositories and Services.

The only project that should reference Repositories would be Services. This way, other projects wouldn’t have access to the repositories. Of course, nothing is to stop a developer from including the repositories project to the controllers project, but hopefully at this point they’ll be asking themselves why it wasn’t included in the first place.