03/01/20161 A MODEL FOR VARIABILITY DESIGN RATIONALE IN SPL Ismênia Galvão, Pim van den Broek & Mehmet Akşit VARI-ARCH 2010, Copenhagen, DK 23/08/2010

23/08/2010VARI-ARCH 2010, Copenhagen, DK 2 INTRODUCTION  Beyond architecture variability specification…  Capturing and communication of the variability rationale  Explicitly handle the design rationale behind architectural variability  Capture assumptions about the design, its variants and invariants  Verification of the variability rationale  Consider that assumptions may become deprecated or invalidated  Detect violation of assumptions

23/08/2010VARI-ARCH 2010, Copenhagen, DK 3 THE VARIABILITY RATIONALE MODEL ELEMENTS RationaleA set of assumptions about artefacts Assumption A statement about the design that is assumed to be true. Can be a claim or an assumed property. ClaimAn assertion of a fact or belief. Property SimpleProperty VarianceProperty A quality the system must have, what it must do or what it should not do. EvidenceThe means by which a fact or belief can be estabilished or disproved.

23/08/2010VARI-ARCH 2010, Copenhagen, DK 4 AN EXAMPLE OF ARCHITECTURE VARIABILITY operation ControlCopy.copyPhoto is crosscutting interface ControlCopy is optional

23/08/2010VARI-ARCH 2010, Copenhagen, DK 5 AN EXAMPLE OF VARIABILITY RATIONALE

23/08/2010VARI-ARCH 2010, Copenhagen, DK 6 What are the main stakeholders and their concerns with respect to variability?  Stakeholders*:  Software architect  Software engineers  Product manager  Concerns:  Communication of variability rationale  Verification of design  Enhancement of variability design  Reuse * All stakeholders that make relevant assumptions about the architecture variability

23/08/2010VARI-ARCH 2010, Copenhagen, DK 7 With respect to which architectural models does the approach consider variability?  The assumptions about variability, defined using variance properties, can be captured for any architectural artefact, at any granularity level.  Sources and targets of claims may also reference any architecture element or variability model element.

23/08/2010VARI-ARCH 2010, Copenhagen, DK 8 How do you integrate variability into a view-based architecture description?  Variability rationale is described within the rationale model, which is orthogonal to architecture models (e.g. component & connector) and to variability models (e.g. feature models).  The integration can be realized by querying the variability design rationale model (in Xtext). The resulting queries can be used to enhance the documentation of architecture variability in any architectural view.