Model-Driven and Software Product Line Engineering - Model-Driven and Software Product Line Engineering - page 109

4.4. Developing core assets
ThedevelopmentofthecoreassetsisthemainstayinSPLE.
Someassetsarecreatedatproblemspacetocapturevariability.
Someothersarecreatedmanuallyfromrequirements,bymodel
designers during the transition from problem space to solution
space or by programmers who have already implemented re-
usable components. In an MDE process, a set of assets is
also generated from the transformation steps and they can be
subject to re-use. At solution space, some specific assets can be
created and subject to re-use in other products.
We summarize the process of deriving MD-SPL as the
incremental transformation of application domains models,
using re-usable model transformation rules, re-usable models,
and re-usable source code to obtain products. Thus, the main
core assets used in MD-SPL approaches are models, model-to-
model transformations, and model-to-text transformations. Of
course, as SPLE approaches, MD-SPL approaches may/must
(re-)use, also, pieces of code already developed and well tested.
The challenge of MD-SPL approaches,regarding core assets
development, lies in selecting when model transformations,
models, or source code must be developed as re-usable core
assets. Sometimes, model structures must be built to be
used in an intermediate transformation when common models
are required. Sometimes model-to-model transformations are
required for either (1) transforming source models into target
models in some transformation step, or (2) weaving models
created by designers or product line architects. Finally,
sometimes source code (or any kind of text descriptor) must
be developed, tested, and intensively re-used.
4.4.1. Developing decision models and deriving products
Given that one objective of MD-SPL approaches is to
automate completely the process of transforming models to