Explicit assumptions enrich architectural models

ABSTRACT

Design for change is a well-known adagium in software engineering. We separate concerns, employ well-designed interfaces, and the like to ease evolution of the systems we build. We model and build in changeability through parameterization and variability points (as in product lines). These all concern places where we explicitly consider variability in our systems. We conjecture that it is helpful to also think of and explicitly model invariability, things in our systems and their environment that we assume will not change. We give examples from the literature and our own experience to illustrate how evolution can be seriously hampered because of tacit assumptions made. In particular, we show how we can explicitly model assumptions in an existing product family. From this, we derive a metamodel to document assumptions. Finally, we show how this type of modeling adds to our understanding of the architecture and the decisions that led to it.

REFERENCES

• 1: Len Bass , Paul Clements , Rick Kazman, Software architecture in practice, Addison-Wesley Longman Publishing Co., Inc., Boston, MA, 1998
• 2: P. Clements and L. Northrop. Software Product Lines: Practices and Patterns. SEI Series in Software Engineering. Addison-Wesley, 2002.
• 3: Hans de Bruin , Johannes C. van Vliet , Ziv Baida, Documenting and Analyzing a Context-Sensitive Design Space, Proceedings of the IFIP 17th World Computer Congress - TC2 Stream / 3rd IEEE/IFIP Conference on Software Architecture: System Design, Development and Maintenance, p.127-141, August 25-30, 2002
• 4: Earl F. Ecklund, Jr. , Lois M. L. Delcambre , Michael J. Freiling, Change cases: use cases that identify future requirements, Proceedings of the 11th ACM SIGPLAN conference on Object-oriented programming, systems, languages, and applications, p.342-358, October 06-10, 1996, San Jose, California, United States
• 5: A. Enders and D. Rombach. A Handbook of Software and Systems Engineering -- Empirical Observations, Laws and Theories. The Fraunhofer IESE Series on Software Engineering. Addison Wesley, 2003.
• 6: Huw Evans , Malcolm Atkinson , Margaret Brown , Julie Cargill , Murray Crease , Steve Draper , Phil Gray , Richard Thomas, The pervasiveness of evolution in GRUMPS software, Software—Practice & Experience, v.33 n.2, p.99-120, 1 February 2003 [doi>10.1002/spe.498]
• 7: S. Fickas , M. S. Feather, Requirements monitoring in distributed environments, Proceedings of the 2nd International Workshop on Services in Distributed and Networked Environments, p.93, June 05-08, 1995
• 8: Martin Fowler, Who Needs an Architect?, IEEE Software, v.20 n.5, p.11-13, September 2003 [doi>10.1109/MS.2003.1231144]
• 9: David Garlan , Robert Allen , John Ockerbloom, Architectural Mismatch: Why Reuse Is So Hard, IEEE Software, v.12 n.6, p.17-26, November 1995 [doi>10.1109/52.469757]
• 10: K. Kang, S. Cohen, J. Hess, W. Novak, and S. Peterson. Feature-Oriented Domain Analysis Feasibility Study. Technical report, Software Engineering Institute, 1990.
• 11: P. Lago and H. van Vliet. Observations from the Recovery of a Software Product Family. In Proceedings of the Software Product Lines Conference, Lecture Notes in Computer Science, pages 214--227, Boston, USA, Aug. 2004. Springer Verlag.
• 12: Nico Lassing , Daan Rijsenbrij , Hans van Vliet, How well can we predict changes at architecture design time?, Journal of Systems and Software, v.65 n.2, p.141-153, 15 February 2003 [doi>10.1016/S0164-1212(02)00056-0]
• 13: Joseph Latimer , Ai-Mei Chang, A Model of Structured Discourse for Cooperating Intelligent Agent, Proceedings of the 29th Hawaii International Conference on System Sciences (HICSS) Volume 2: Decision Support and Knowledge-Based Systems, p.191, January 03-06, 1996
• 14: Kenneth C. Laudon , Jane Price Laudon, Management Information Systems: Managing the Digital Firm, Prentice Hall PTR, Upper Saddle River, NJ, 2001
• 15: M. Lehman. Software Evolution -- Cause or Effect. Stevens Memorial Lecture, http://www.cs.mdx.ac.uk/staffpages/mml, 2003.
• 16: M. Lehman and L. Belady, editors. Program Evolution. Number 27 in APIC Studies in Data Processing. Academic Press, 1985.
• 17: Edward Lewis, The Use of the SAGA Tool for Gathering Requirements for Future Information Systems, Proceedings of the 29th Hawaii International Conference on System Sciences (HICSS) Volume 2: Decision Support and Knowledge-Based Systems, p.269, January 03-06, 1996
• 18: Karl J. Lieberherr, Adaptive Object-Oriented Software: The Demeter Method with Propagation Patterns, PWS Publishing Co., Boston, MA, 1995
• 19: Juha Savolainen , Juha Kuusela, Consistency Management of Product Line Requirements, Proceedings of the 5th IEEE International Symposium on Requirements Engineering, p.40-47, August 27-31, 2001
• 20: S. Uchitel and D. Yankelevich. Enhancing Architectural Mismatch Detection with Assumptions. In In Proc. of the Eng. of Computer Based Systems (ECBS 2000), pages 138--147, Edinburgh, Scotland, Apr. 2000.
• 21: T. Weiler. Modeling Architectural Variability for Software Product Lines. In J. van Gurp and J. Bosch, editors, Proceedings of the Workshop on Software Variability Management, pages 55--63, Gröningen, The Netherlands, Feb. 2003.
• 22: Daniil Yakimovich , James M. Bieman , Victor R. Basili, Software architecture classification for estimating the cost of COTS integration, Proceedings of the 21st international conference on Software engineering, p.296-302, May 16-22, 1999, Los Angeles, California, United States [doi>10.1145/302405.302643]

INDEX TERMS

Primary Classification:
  D. Software
  D.2 SOFTWARE ENGINEERING
        D.2.11 Software Architectures

General Terms:
Documentation

Keywords:
architecture model, assumption, documentation, knowledge management, software architecture