Books for you

Let ??™ s select start car usage as our fi rst use case.
When describing exceptions and variants of a use case fl ow, we quickly hit the
limits of our natural language. It is normally easier to describe all these sorts of
junctions, concurrencies, and terminations graphically. SysML and UML offer the
activity diagram to graphically describe exceptions and variants.
First of all, let ??™ s look at the essential steps of our use case. A step becomes
an action in the activity. It ??™ s now a matter of connecting the actions, i.e., putting
them in a certain sequence. The fl ow begins at the initial node, denoted by a black
circle, followed by the actions, and fi nally the activity fi nal node, which is also
denoted by a black circle with an additional encompassing circle.
We don ??™ t consider potential exceptions and variants just yet, which means that
the result can be pretty trivial. Though the essential description does not dictate
a fi xed sequence, the steps are already listed in a meaningful order rather than
meaninglessly mixed at random.


Pages:
187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211