问题
Recently, I found my way to The Clean Architecture post by Uncle Bob. But when I tried to apply it to a current project, I got stuck when a usecase needed to depend on another usecase.
For example, my Domain Model is Goal and Task. One Goal can have many Tasks. When I update a Task, it needs to update the information of its parent Goal. In other words, UpdateTask usecase will have UpdateGoal usecase as a dependecy. I am not sure if this is acceptable, or, if we should avoid usecase level dependencies.
回答1:
A use case is related to a functionality of your application. Generally when we need to invoke from one use case to another there is something that does not work.
When you update a goal in isolation, it is not the same scenario as when you update it by a change in a task, in fact, it is sure that not all data is updated, but a part.
Surely you will have to use the goal repository and the goal entity but it is a completely different scenario. In your case you are not duplicating logic, only calls to the repository or the entity, saving code lines can be expensive in the future.
In short, it is not a good idea to have dependence between use cases.
来源：https://stackoverflow.com/questions/40458666/the-clean-architecture-usecase-dependencies