Non-Functional Requirements Software Architecture Design David Ameller

260 Pages·2013·3.33 MB·English

Non-Functional Requirements
as drivers of
Software Architecture Design
David Ameller
Thesis supervised by
Dr. Xavier Franch
A thesis submitted in partial fulfillment
of the requirements for the degree of
Doctor of Philosophy in Computing
Departament de Llenguatges i Sistemes Informàtics
Universitat Politècnica de Catalunya

Abstract
In the last decades, software engineering has become an important area of
research. As researchers, we try to identify a problem, a need, or a hole in
some research topic, once identified we make an effort to produce new tech-
niques, methods, and tools that hopefully will help to improve the detected
issue. In the present thesis the identified issue was the need of supporting
non-functional requirements in the software architecture design where these
requirements are the drivers of the architectural decision-making.
This thesis started with the idea that a relatively new software engi-
neering discipline, model-driven development, was a good place to propose
a solution for the detected issue. We envisioned how non-functional re-
quirements can be integrated in model-driven development and how this
integration will impact in the architectural design activities.
When we started to produce our techniques, methods, and tools for
model-driven development we found out that there was a bigger hole in the
web of knowledge than what we had initially foreseen. Much of the evidence
of how non-functional requirements affect the software architecture design is
hidden. Thissituationcausedaturninthisthesis: weneededtounderstand
architects, how they think and how they make the architectural decisions,
what is the role of non-functional requirements in the architectural decision-
making process, and to what extent are the non-functional requirements
important in this process. All these questions needed an answer, an answer
thatonly architectscould provide. Inconsequenceweopted todroveseveral
empirical studies to answer these questions.
I
ABSTRACT
In parallel, we started to work in a way of representing this knowledge,
an ontology for software architecture that integrates non-functional require-
ments. Using this ontology as basis, we designed a method to assist archi-
tects in the architectural decision-making process and a tool that acted as
a proof of concept of both, the ontology and the method.
In summary, this thesis explores how non-functional requirements are
currently integrated in the software architecture design practices, and pro-
poses ways to improve this integration and facilitate the work of architects
by providing means to assist them in the architectural decision-making pro-
cess.
II
Co-authorship statement
Most of the contents in this thesis are based on published papers authored
by the candidate, and in some cases co-authored with other authors. The
contentsofthepapersincludedinthisthesismayhavebeenadapted,reorga-
nized, and extended with respect to the published version. The contribution
for each chapter is described, including specifically who contributed to the
work and the nature and extent of his/her contribution.
All thesis chapters
Dr. Xavier Franch, as supervisor, has contributed to the research described
in this thesis. Xavier’s has been active and involved in the research being
conducted,discussing,andwritingeachpaper. Hisguidanceandsupervision
has been fundamental for the selection of conference and journal targets for
publications and the improvement of English writing skills.
Chapter 3
This chapter is based in [24], which was co-authored with Dr. Jordi Cabot,
associate professor at the École des Mines de Nantes and the leader of the
AtlanMod team. Jordi participated in the discussions of this research giving
his opinion, in particular his expertise in Model-Driven Development was of
great value for this research. He also helped in the writing of the paper.
III
CO-AUTHORSHIP STATEMENT
Chapter 5
Thischapteriscomposedbythreeempiricalstudies. Whilethefirstonewas
performed with Dr. Xavier Franch alone, the other two were in collabora-
tion with other researchers. The second empirical study is based in [11, 12],
which was co-authored with Dr. Claudia Ayala, researcher at the Universi-
tat Politècnica de Catalunya and Dr. Jordi Cabot, previously introduced.
Claudia was the expert in driving empirical studies, and proposed the pro-
tocol to follow, she also participated in the execution of the study and in
the writing of the papers. Jordi participated in most of the discussions of
this research and helped in the writing of the papers. The third empirical
study is based in [25], which was co-authored with Dr. Matthias Galster, re-
searcherattheUniversityofCanterbury, andDr. ParisAvgeriou, researcher
at the University of Groningen and leader of the SEARCH group. Matthias
produced the first version of the research protocol and helped in the writing
of the paper. Paris participated in most of the discussions of this research
giving his opinion, in particular his expertise in software architecture was of
great value for this research. He also helped in the writing of the paper.
Chapter 7
The Section 7.3 of this chapter is based in the papers [14, 15], which were
co-authored with Oriol Collell. Oriol was the main developer of the Ar-
chiTech tool, and he also helped in the preparation of the tool demo and the
promotional video.
IV
Acknowledgments
This research project would not have been possible without the support of
many people. The author wishes to express his gratitude to his supervi-
sor, who was abundantly helpful and provided extremely useful assistance,
support, and guidance.
Special thanks also to all his research group members and university
colleagues; for their invaluable assistance. Not forgetting his best friends
who always have been there.
The author wishes to express an special gratitude to his mother and
father, and to his relatives; for their support during his studies.
The following is the list of people, in alphabetical order, that helped in
one way or another to the completion of this thesis.
Antonio Vallecillo David Ruiz Oriol Collell
Antonio Villegas Frank Buschmann Oscar Cabrera
Borja Balle Hugo H. Pibernat Oscar Hernan
Carles Farré Jaelson Castro Oscar Pastor
Carlos Ameller Jordi Cabot Paris Avgeriou
Charlie Ameller Jordi Marco Paul Grünbacher
Claudia P. Ayala Judith Mitchell Raul Marina
Cristina Gómez Lidia López Rebeca Dalmau
Cristina Palomares Marc Oriol Silverio Martínez
David Aguilera Matthias Galster Vicente Pelechano
David Cerdan Nadia Ameller Xavier Franch
V
ACKNOWLEDGMENTS
VI
Contents
Abstract I
Co-authorship Statement III
Acknowledgments V
Contents VII
List of Tables XI
List of Figures XIII
1 Introduction 1
1.1 Context and terminology . . . . . . . . . . . . . . . . . . . . . 1
1.1.1 Requirements Engineering . . . . . . . . . . . . . . . . 1
1.1.2 Software Architecture . . . . . . . . . . . . . . . . . . 4
1.1.3 Model-Driven Development . . . . . . . . . . . . . . . 5
1.2 Research questions . . . . . . . . . . . . . . . . . . . . . . . . 7
1.3 Methodological approach . . . . . . . . . . . . . . . . . . . . . 9
1.4 Research contributions . . . . . . . . . . . . . . . . . . . . . . 11
1.4.1 Integration of NFRs into MDD . . . . . . . . . . . . . 11
1.4.2 Empirical research in software architecture . . . . . . . 12
1.4.3 Architectural knowledge . . . . . . . . . . . . . . . . . 13
VII
CONTENTS
1.4.4 Other publications . . . . . . . . . . . . . . . . . . . . 14
1.4.5 Statistics of the published works . . . . . . . . . . . . 16
1.5 Structure of the dissertation . . . . . . . . . . . . . . . . . . . 17
I NFRs in Model-Driven Development 19
2 State of the art 21
2.1 Modeling languages supporting NFRs in MDD . . . . . . . . 22
2.1.1 Extending modeling languages to represent NFRs . . . 22
2.1.2 MDD with support for RE modeling languages . . . . 23
2.1.3 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . 25
2.2 Processes that support NFRs in MDD . . . . . . . . . . . . . 25
2.2.1 NFR-driven transformations . . . . . . . . . . . . . . . 26
2.2.2 NFRs as validating mechanism . . . . . . . . . . . . . 26
2.2.3 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3 Introducing NFRs in MDD 29
3.1 State of the practice . . . . . . . . . . . . . . . . . . . . . . . 29
3.1.1 NFRs supported with manual adaptation . . . . . . . 30
3.1.2 NFRs supported with new transformations . . . . . . 31
3.1.3 How are NFRs supported in MDD practice? . . . . . . 32
3.2 Motivation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.3 Introducing NFRs in MDD . . . . . . . . . . . . . . . . . . . 37
3.3.1 NFR-aware MDD: NFRs in the PIM . . . . . . . . . . 38
3.3.2 NFR-aware MDD: NFRs for decision-making . . . . . 42
3.3.3 Comparison . . . . . . . . . . . . . . . . . . . . . . . . 44
3.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
3.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
II NFRs in Software Architecture 53
4 State of the art 55
4.1 Empirical studies on NFRs . . . . . . . . . . . . . . . . . . . 56
4.1.1 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . 58
4.2 Empirical studies on software architecture . . . . . . . . . . . 58
VIII