If you dive
into the use case by one detail step deep you get to the essential use case description.
It describes the fl ow of a use case in general and independent of any specifi c
technology. This description is purely textual and is initially not modeled with
special model elements.
While this description looks extremely easy it can be rather diffi cult to create
it. The essential description omits a lot of details, doesn ??™ t consider exceptions but
only the standard fl ow, and contains no technology and design decisions. The targeted
omission of information is called abstraction . Abstraction at this point may
prove to be diffi cult especially for engineers, since they normally have to consider
every detail and every exception.
Table 2.10 Summary: Describe use case essences.
Reference card: Describe use case essences.
Incoming and outgoing data
Requirements:
General requirements to the system.
Use cases:
System provided by the system
::Use cases [essential]:
Use cases with an essential step
description.
Motivation/description
Why? We need an overview of the system ??™ s services that can be determined quickly
and which is independent of technical solutions.
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