I think the commenter generally views things as code acting on entities. If so, that code is suited to being called an xxxManager, or xxxService, or xxxCoordinator, or xxxController. Of course we have returned to a place in history by doing so, of creating big balls of mud as complexity increases.
Peter Coad advocated against this in favor of modeling the problem domain under consideration using an object oriented approach.
In an object oriented domain model there is no place for such external “controllers”, but I think the commenter doesn’t propose this approach.
I have an object called TransportMaster, with concrete implementations X_TransportMaster, Y_TransportMaster, Z_TransportMaster. The application instance may contain any number of any mixture of these objects, and they may be created and destroyed at any time by the user. Their use within the application is also subject to the user's whims.
Why would a TransportMasterManager, which provides factory methods, enumerations, a collection of the current set of TM's, and knowledge of the current user choice for which TM's is being used for what, have "no place" in this design?
>modeling the problem domain under consideration using an object oriented approach
Really curious. Do you have any material that explains this way of design?
I work on mostly web apps. End of the day, it's really about moving data and transforming data. So most of my programs have no choice but to deal with data, and so, my whole design process revolves around gathering, storing, operating upon and transferring data.
I don't know Peter Coad, but the approach reminds me of domain driven design (DDD). Most business logic would be in objects named entities, but DDD has also services, since there might be logic that affects multiple entities (actually special entities called "aggregate root").
Peter Coad did write a number of books, which are pretty old and likely out of print. How to actually model a complex system into an object oriented domain model, is something I have long thought to teach. However, sadly there seems little appetite in a world currently dominated by procedural code acting on data, modeled using functional decomposition or through a relational data model. Of course our industry will eventually relearn the forgotten lessons and methods of the past, rename them as something new, and adopt them as the new silver bullet for software development.
Peter Coad advocated against this in favor of modeling the problem domain under consideration using an object oriented approach.
In an object oriented domain model there is no place for such external “controllers”, but I think the commenter doesn’t propose this approach.