• Abstract and Figures
• Public Full-text

Supporting Software Architecture Evolution Blekinge Institute of Technology Doctoral Dissertation Series No. 2003:03 Supporting Software Architecture Evolution Architecture Selection and Variability Mikael Svahnberg Mikael Svahnberg Department of Software Engineering and Computer Science ISBN 91-7295-025-0 Blekinge Institute of Technology Blekinge Institute of Technology Doctoral Dissertation Series No 2003:03 ISSN 1650-2159 ISBN 91-7295-025-0 Supporting Software Architecture Evolution Architecture Selection and Variability Mikael Svahnberg Department of Software Engineering and Computer Science Blekinge Institute of Technology Sweden Blekinge Institute of Technology Doctoral Dissertation Series No. 2003:03 ISSN 1650-2159 ISBN 91-7295-025-0 Published by Blekinge Institute of Technology © 2003 Mikael Svahnberg Cover photography, “Heliga Kors Kyrka” © 2003 Mikael Svahnberg Printed in Sweden Kaserntryckeriet, Karlskrona 2003 This thesis is submitted to the Faculty of Technology at Blekinge Institute of Technology, in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Software Engineering Contact Information Mikael Svahnberg Department of Software Engineering and Computer Science Blekinge Institute of Technology PO Box 520 SE-372 25 Ronneby SWEDEN E-mail: [email protected] Abstract Today it is more a rule than an exception that software systems have a lifecycle of more than several years. Hence, software evolution is inevita- ble. During the life span of a software system the domain in which the system is working evolves and changes. This causes changes to the soft- ware system, and the software system may also be evolved to satisfy new markets. The ability to evolve gracefully, and thus the long-term success of a software system, is to a large extent governed by its software archi- tecture and the ability of the software architecture to fulfil requirements on quality attributes and to adapt to evolving requirements. In this thesis we study evolution of software architectures and what can be done to support this evolution. We focus on three particular aspects of evolution support: how to ensure that the correct blend of quality attributes is met (architecture selection), the technical means available for supporting changes in the software system (variability), and what types of changes that are likely to occur during evolution (categories of evolution). We introduce a method for architecture evaluation and selection that focus on ensuring that the selected software architecture is the architec- ture candidate with the most potential for fulfilling a particular blend of quality attributes. The method is based on quantification of expert opin- ions and focused discussions where these expert opinions differ. The architecture evaluation and selection method is studied in both an aca- demic and in an industry setting. We also introduce a taxonomy of techniques for realising variability in a software system and study how the techniques in this taxonomy are applied in different evolution situations. The taxonomy is based on sev- eral industry case studies. Two industry cases are studied in further detail and the evolution of these systems are followed over a number of releases and generations. During this evolution it is shown how variability mecha- nisms are used to also support evolution, and that there are typical cases of evolution that a software system can be prepared to cope with. The contribution of this thesis is that it increases the understanding of how evolution occurs in a software system, how to create software that is flexible enough to support evolution and how to evaluate and select a software architecture that meets a particular blend of quality attributes. Together this ensures that a software system is based on a software archi- tecture that fits the current quality requirements and that is flexible in the right places so that it is able to evolve gracefully. i Acknowledgements First, I would like to express my gratitude to my advisor Prof. Claes Wohlin, who is always an invaluable source of ideas, criticism and cheerful prod- ding. Thanks to Prof. Jan Bosch, my advisor during my first two years, for offering me this chance and for helping me through the early phases. Thanks to Dr. Michael Mattsson for always having plenty of inspiring ideas. For fruitful cooperation I also thank Prof. Lars Lundberg and Dr. Jilles van Gurp. I would also like to thank my colleagues (including but not limited to the SERL research group) that have contributed with ideas and input, as well as participation in different investigations. I would like to thank the companies I have had the pleasure of working together with during different phases of my Ph.D. studies: Axis Communi- cations, Ericsson, UIQ Technology and Danaher Motion Särö. As always, I am grateful to my parents, Alison and Kenneth, for their inces- sant support and for helping me achieve all this. My brother Charlie has also been a valuable source of inspiration. Finally I thank all my friends, without whom life would be quite dreary. ii Contents CHAPTER 1 Introduction..................................................................1 Outline of Thesis ........................................................................... 4 Research Approach........................................................................ 4 Concepts and Related Work ..........................................................16 Part I Software Architecture Evaluation and Selection CHAPTER 2 A Software Architecture Vision .....................................43 Contribution of Part I....................................................................44 Outline of Part I ...........................................................................45 Architecture Evaluation and Selection.............................................46 CHAPTER 3 Architecture Evaluation and Selection ...........................49 Scope and Goal of Chapter............................................................50 Context of Method........................................................................50 Architecture Evaluation and Selection.............................................52 A Case Study Using the Method.....................................................61 Discussion....................................................................................66 Summary and Conclusions ............................................................66 CHAPTER 4 Consensus Discussion and Analysis...............................69 Scope and Goal of Chapter............................................................70 Create Individual Frameworks .......................................................72 Discuss Individual Frameworks ......................................................73 Create a Unified Framework ..........................................................75 Evaluation of Unified Framework ...................................................76 Analysis of Framework..................................................................78 Summary and Conclusions ............................................................81 CHAPTER 5 Study 1: Academic Evaluation ......................................83 Scope and Goal of Chapter............................................................83 Study Design................................................................................85 Operation ....................................................................................90 Analysis and Interpretation ...........................................................91 Summary and Conclusions ............................................................97 iii CHAPTER 6 Evaluation using Multiple Sources...............................101 Scope and Goal of Chapter..........................................................102 Comparing Two Views ................................................................103 Analysis and Interpretation .........................................................108 Summary and Conclusions ..........................................................109 CHAPTER 7 Study 2: Industrial Application....................................111 Scope and Goal of Chapter..........................................................111 Planning ....................................................................................113 Operation ..................................................................................119 Analysis and Interpretation .........................................................123 Summary and Conclusions ..........................................................128 CHAPTER 8 Composing the Evaluation Team ................................131 Scope and Goal of Chapter..........................................................131 Research Method........................................................................132 Data Sets...................................................................................136 Analysis .....................................................................................136 Discussion..................................................................................142 Summary and Conclusions ..........................................................143 CHAPTER 9 Summary and Conclusions .........................................145 Summary and Conclusions for Part I ............................................145 Future Work...............................................................................147 Part

Load more

  289

Copy Link