Feature request: Add a beCalledInClassesThat conjunction

[cpoissonnier]

I wanted to implement a rule like this one :

@ArchTest
    static final ArchRule events_must_be_created_by_aggregates =
            noConstructors().that().areDeclaredInClassesThat().areAssignableTo(Event.class).should().beCalledInClassesThat().areNotAssignableFrom(Aggregate.class)
                    .because("the aggregate should manage its own lifecycle and events");

But it seems that it is now possible without custom predicate.
Is that something that could be added in the ready-to-use conjunctions ?

For reference, the related Stackoverflow question : https://stackoverflow.com/questions/69723542/how-to-check-that-a-constructor-is-called-in-the-right-classes-with-archunit/69728892#69728892

[codecholeric]

Yes, I think this surely makes sense to be added 🙂
I think it should in fact be added to CodeUnitsShould, so it can be automatically used for methods()...should() and constructors()...should() (and semantically it makes sense for both). And maybe beCalledByClassesThat is a tiny bit nicer as a name 🤔 🤷‍♂️

Of course we could even go a step further and make it

should().beCalledBy().{classesThat()/methodsThat()/constructorsThat()}

But managing expectations: If it is up to me to implement this, it will take quite some time as my ArchUnit task queue is always at the limit 😉 But if anyone wants to jump in and create a PR, I think this would be a nice addition 😄

[JKLedzion]

Hi, I’ve started working on this issue (hope it’s Ok and it’s still open) and I’ve added a PR with initial part which I’ve done. Work is in progress but it would be great to receive some feedback if it goes in right direction.

I’ve started from adding method onlyBeCalledByClassesThat(DescribedPredicate predicate) to CodeUnitsShould.
Now I’m working on possibility to have a rule like:
should().onlyBeCalled().{byClassesThat()/methodsThat()/constructorsThat()}.

Could you also let me know if my understanding of the issue is correct for below points?

1. I’ve implemented condition “code unit should only be called by”, but few possibilities came to my mind, not sure if I’ve decided on the correct one:
   • code unit should be called only by classes that,
   • code unit should be called by at least one class that,
   • code unit should be called by all classes that (but can be called also by other)
   • code unit should be called by all classes that (and can’t be called by any other).
2. should().onlyBeCalled().byMethodsThat() - here I’m checking if methods calling selected code unit meet provided criteria but still this code unit can be called by constructors not meeting criteria. Is it correct?

I would appreciate any feedback.
Justyna