Have I to use the same actors for those extending or included use cases? [closed]

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I am currently refreshing/altering my knowledge in software development because I will work in this area soon. We have learned a lot about UML diagrams and coding at University, but I have never brought it all together in a real Project. Therefore, I started to create a test web-app in Grails, and I wanted to begin with a requirements analysis and use cases too keep it close to reality.

My web-app should allow users to share recipes, find recipes and review recipes by other users. Every recipe has many ingredients, which are not just strings but rather entities so that calories, fat, protein and carbs can be used to automatically calculate nutrition facts of a certain recipe.

An ingredient can be added to the database by either a consumer or nutrition expert. If it is created by a consumer, it is only a "prospective" ingredient, meaning that it has to be verified by an administrator to become a "proper" ingredient -- otherwise it is marked, e.g. red text color.

This is my current use case diagram:

http://ubuntuone.com/0zDw9kEbj1BwtXjnCtxdwC

My question here is:

• If I use include or extend, will I have to use the same primary actors for those extending or included use cases? (In the screenshot: Could AddProspectiveIngredient have a different primary actor than CreateRecipe? Same question for include)

EDIT: I don't think the question is asked broadly: If I use include or extend, will I have to use the same primary actors for those extending or included use cases?

I agree, as this was one of my first questions on Stackoverflow, that there is some unnecessary boilerplate in the beginning. If that is the case, I can edit my question to keep it open. I am still hoping for someone to stumble upon it and provide me with more knowledge or sources.

Answer 1

If I use include or extend, will I have to use the same primary actors for those extending or included use cases?

Extend means that one Use case is a variation of another one. It is the definition, sorry. So, I am not sure you really meant it, but different variations of activity can be easily conducted by different actors.

As for include, it is not so simple. One behaviour is inserted in another one. It is some variation for generalizations for use cases.

So, if behaviour A includes B, and actor X is connected only to A and actor Y is connected only to B, that means, that Y really makes A, too, only not all of it. X has all behaviour of Y and some additional behaviour. And that means that X is derived from Y, or X is a subclass of Y.

Simply, if you have different not-tied actors for A and B, you have simply mistaken. They ARE tied.