Annotations for ports and adapters (hexagonal)

[flavius]

Initially I was asking for something which already exists.

However found something missing:

Is there an annotation for the UseCase abstraction?

Alistair Cockburn calls these primary ports of the domain model and names them For<business-processs>

[odrotbohm]

Can you point me to an authoritative resource defining that? AFAIK, UseCases are only an abstraction in Clean Architecture, not Hexagonal.

[ghferrari]

I believe there is some discussion/dispute about this. (See e.g. the discussion of Hexagonal Architecture and DDD (Domain Driven Design) at https://www.happycoders.eu/software-craftsmanship/hexagonal-architecture/ ).

In any case, a primary port must have some implementation which is inside one's hexagonal application, and I for one think these things fit the definition of use cases.

Tom Homberg's book Get Your Hands Dirty on Clean Architecture , which promotes hexagonal architecture as a form of, or at least, close relation to clean architecture, also includes use cases. See https://reflectoring.io/book/ .

So, I think it's at least permissible to use the concept of use cases within HA, even if some would say not absolutely required.

[acemoo]

Hexagonal Architecture has no use cases.
There's just

• the app
• ports (driving and driven / primary and secondary)
• adapters (driving and driven / primary and secondary)
• the configurator

Some authoritative sources would be:

• A presentation from Alistar Cockburn https://www.youtube.com/watch?v=k0ykTxw7s0Y
• A book written by Alistar Cockburn and Juan Manuel Garrido de Paz https://www.amazon.com/Hexagonal-Architecture-Explained-Alistair-Cockburn/dp/173751978X

Hexagonal Architecture does not care what you do inside the app. (as long as you implement the driving ports and don't call anything outside the app without using a driven port)
You're free to use use cases inside your app, but that's not something that's part of Hexagonal Architecture.