This section sets out the justification
behind the choice of standards for component or “white-box” use case
What is a Component Level Use Case
A use case defines a contract between an
actor and system by describing their dynamic interaction.
By manipulating what is understood by the
scope of the system, different actors may be described. This is what
differentiates Component Use Cases to black-box use cases (henceforth
called UCs). In the former, the scope of the system is a component (or
part of an enterprise), in the latter it is the entire enterprise.
Figure 1: showing relationship of system scope to choice
This can be aided by explicitly showing the system boundary “box” in
the Use Case model (UCM) – however Rose does not directly support this, so
the note should be used.
Who is interested in it
The clue is in the actor of the UCM – which is directly driven by the
scope of the system:
Where the scope is GCS, the actor reflects the stakeholders of the
system, and are often end users, therefore the main audience of this
artefact is for requirements validation. Additionally since the use case
describes something end-to-end, enterprise architects, planners and
integrator will be also reviewing the document.
Where the scope is a component, the actor is usually another component
–– then the stakeholders are really the individuals involved in building
the component or interfacing with the component. However this does not
mean that the vocabulary should be technical, since these still need to be
validated by a broader community.
Although in the case of security these goals can often be the mitigation
of key, named risks.
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