Accordingly, we called
an essential step unlock car and not unlock auto in the use case car usage .
We can formalize our search for identical fl ows by means of pre- and postconditions
as well as incoming and outgoing data. This information can be modeled
as we will see later on in Section 2.4.5. And we can use query scripts to access
it from within the model. A script can create a list of use case steps that have the
same pre- and postconditions or the same incoming and outgoing data. These are
potentially identical steps. Most SysML/UML tools allow you to develop tailored
model query scripts.
However, there are neither pre- and postconditions nor information about
incoming and outgoing data on the essential level yet. We can apply this technique
only to more detailed use case fl ows later on.
A use case step that occurs more than once or related use case steps are modeled
as one single new use case. However, since the criteria for a fully fl edged use
case??”no trigger, result, or actor??”are not met, 14 we denote it with the stereotype
?«secondary?» or as a dashed ellipse.
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