Quality Assurance in the Presence of Variability - Intentional Perspectives on Information Systems Engineering - page 316

• An optional variability dependency between a variation point and a variant

describes that this variant can be selected but does not need to be selected. An
optional variability dependency is drawn as a dashed line.

• An alternative choice is a specialization of optional variability dependencies. An

alternative choice group comprises at least two variants which are related to a
variation point by optional variability dependencies as shown in Fig. 1. The min,
max bounds define how many variants of the alternative choice group must be
selected at least (min) and how many variants can be selected at most (max).

In addition to variability dependencies, the OVM allows defining constraint
dependencies to document additional dependencies between variation points and
variants, e.g. to enforce that two variants of different variation points cannot be
selected together.
Variability in the domain artifacts is modeled by using so called artifact depen-
dencies between the elements of the OVM and the domain artifacts. Variants in
the OVM are related to variable elements in the reusable artifacts via those arti-
fact dependencies. A simple example of an artifact dependency is shown in Fig. 2
in Sect. 4. Whenever a variant in the OVM is selected for a concrete product, the
related elements in the reusable artifacts will be included in the derived artifacts of
the product. Elements of the domain artifacts that are not related to a variant in the
OVM are considered as a common artifact and are therefore part of every product
that is derived.

orthogonal variability model

VP

variation point

Behaviour on
Closing

alternative
variability
dependency

[1..1]

V

V 1 : flashing
yellow on closing

V

V 2 : yellow
on closing

variants

traffic light gate

gate closed?

gate closed!

open gate? open gate!

red

close

gate closed?

yellow
flash

yellow
red

yellow

closing opening

close gate?

green

open

gate open?

close gate! gate open!

close gate?

properties

If gate is closing, light is flashing yellow / AG(closing yellow flash).

If gate is closing, light is yellow / AG( closing yellow ).

sendable messages are followed by '!', receivable messages are followed by '?'

Fig. 2 Simplified example of domain artifacts