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Another example is a requirement specifying that only
one room can have automatic windows. This requirement
defines the requirement
(R1)
, specifying that windows must
be localized in the same room. Then, only
Window
elements
from the same
Room
element can be bound to the
Automatic
Windows
feature.
We also use the structural dependency property to
describe dependencies between bindings. For example, the
requirement
(R4)
,whichspecifiesthatonlyautomaticwindows
can be selected from rooms that are not configured to have
air conditioning, implies that a
Window
element can be
bound to the
Automatic Windows
feature only if the
Room
element where the window is located is not bound to the
Air
Conditioning
feature.
We express the value of the property
D
as a set of
OCL sentences (see section 3.3). For example, for the
requirement
(R3)
a product line architect must set the
structural dependency property of the
constraint1
to
D =
{
sensor
− >
notEmpty()
}
.
5.2.5.
The
constraint
metamodel
and
the
binding
metamodel
Constraint and binding models have their own metamodel,
which is described in this section.
5.2.5.1.
The constraint metamodel
We have created a
constraint metamodel
to facilitate the
creation of constraint models. Our constraint metamodel is
based on our feature metamodel (see Figure 4.10).We extended
its semantics to include the constraints for managing binding
models.
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