Is it possible to join 2 controller classes to 1 boundary class?

Question

I'm doing a college project where I'm required to create a class diagram to a school registration system. There I have included a Student class, a registrationUI Boundary Class and a registrationController controller class:

I have created a separate controller class called systemController to do the other tasks such as calculate bill, etc...

I'm asking if it's possible to join the systemController class with the registrationUI class.

Answer 1

ECB architectural pattern

It can be useful to realize that the ECB architecture pattern originates from the use case models:

• a controller represent a use case (e.g. RegistrationControler for use case "Register Student"). A controller is linked to all the entites that are involved in the use case (can be several, e.g. Registration, Student and Course)
• boundaries connect the use case with the involved external actors (e.g. RegistrationUI offers the user interface to the registration manager, or to a student if it's a self service system). So several boundaries can be linked to a controler (for example if a secondary actor is involved such as a third party system).
• entities represent domain objects (e.g. Student). So an entity can be linked to several other related entities (e.g. Registration record for the Student in a Course)

Consistency check

At the bottom of this article or that article you'll see a short matrix showing the possible relations between entities, controls and boundaries.

According to this logic, entities [should never be directly connected to a boundary. So your Access relation between Student and RegistrationUI is not a good idea (ECB is not MVC).

One boundary and two controllers ?

If you follow Jacobson's OOSE logic of decomposing a use case into boundaries and controllers, or if applying a basic step by step robustness analysis in a use case driven modeling approach, you'd identify the controllers (use cases) and create a boundary for each link between an actor and the use case. So at first sight, one could think that a boundary can be linked to at most one controller.

But you there are also "included" use cases or "extended" use cases. These are not connected directly to an actor, at least not explicitly in the graphic. This means that you could very well have one boundaries related to several controllers. In this tutorial you have a very nice ATM example with one boundary and several ATM transactions. In the DDJ article link above, you also have a similar example.

P.S.: Personally, I'm not quite sure what you want to achieve with the systemController. I suggest that you think about its role and its name. Looking at it's content, I could imagine that it's a part of the RegistrationController. Bt I could also imagine that it's a dispatcher launching the other controllers.