Now let's go back to the distinguishing aspects of
RUP, starting from the first one. That is, that the
rational unified process is use-case driven. So let's see what
that means. Generally speaking, we can see a system as
something that performs a sequence of actions in response to
user inputs. So the user submits some requests, or requests
some functionality, and the system responds to those requests. Use
cases, as we just said, capture exactly this interaction and
answer the question, what is the system supposed to do
for each user? So, this is a very important point.
So they can represent what a system can do for
each of the different types of users of the system.
For this reason, and as we will see in more
detail, in the rational unified process, use cases are a
central element of the whole development life cycle. From requirements
engineering, all the way through the process until testing and maintenance.
So, once more, use cases are used to support and
help each one of these phases in the rational unified process.