Model-Driven and Software Product Line Engineering - Model-Driven and Software Product Line Engineering - page 124

define the required execution ordering of such transformation
rules to derive configured products.
4.6.1. Transformation rules in the Smart-Home systems
SPL
As we introduced before (see Figure 4.3 and Figure 4.13),
the transformation rules we have created for our application
example are used in four stages.The first set of rules is defined
from the domain metamodel to the facilities metamodel.
They are created taking into account the facilities feature
model. The second set is defined from the facilities metamodel
to the components metamodel. The third set is defined from
the components metamodel to the architecture metamodel,
taking into account the architecture feature model. Finally,
the fourth set of transformation rules includes model-to-text
transformations,which produce the source code of product line
members.
First stage: Domain-to-facilities transformation rules. The
purpose of these transformation rules is the adding of
information about Smart-Homes' facilities to domain models.
These are horizontal model-to-model transformations. It
means, they transform models inside the same abstraction
level, the application domain abstraction level, by adding
concerns related to Smart-Homes' facilities.
In this stage, we create two sets of transformation
rules: the base and the specific ones. On the one
hand, base transformation rules do not depend on any
variant of the product line. They are responsible for
building the common or base product. Thus, they are
always executed during the transformation process.
For instance, we create a base transformation rule to
transform Domain metamodel::House elements into
FacilitiesMetamodel::House elements. Similarly,
we create a base transformation rule to transform