In my researches, I met these 3 cases. Even though description of a Class is not so common. But I do not agree on the "bad practice to use Activity Diagram to model the whole process" under the first point.
It is true that many are making mistakes when they do so but it is actually a very good way to describe in details. The problem is that most people are trying to model with the fewest diagrams possible and THIS is the bad decision. To get a good Activity Diagram you need many levels to give a good description.
Say we start at what I call a top level with very widespread Actions. Then you create a new diagram to model every Action (these are not Action then but Activities). After having your "second level", do the same again to create a third level.
It may be easier with an example:
We have a company producing and selling stuff. We create a very "high level" digram that looks like:
receiving an order -> sending it to production -> sending the finished product AND sending the bill -> finishing when we get paid.
That was a too simple one, but good enough for my example. When this is done, you go to the next level. This means go into every actions and "describe it" with a new diagram. Here in my example, I'll take the "receiving an order":
picking up the phone -> checking what we have in the warehouse -> create an offer to the customer -> sending the order to production.
Then again we could "split" these into smaller Activities to the point where there are only Actions. I define an Action as an Activity where there is only one "process".
Now I hope you understand my point.
I do get that many don't bother. And it is probably easier doing this with other diagrams than only Activity.
Anyway thank you very much for those comments. It helps a lot
Geo
