Software Architectures Advances and Applications

We have recently seen a renewal of interest in the field of software architectures. This has happened within the object-oriented community - with the emergenceofframe­ works and patterns- but also within a wider context of software engineering- with the concepts of components and component-based development. Work is now pro­ ceeding apace with new developments coming very rapidly. In such an environment it is easy to lose some important ideas; the need for a reflective view on what will be the lasting developments led us to organise a two day seminar in the Open University as a checkpoint in current development. To this end we gathered field-leaders from both industry and academia to lead a lively discussion and exchange of ideas. This book is a result ofa very successful event. From the outset we were not only interested in the discussion of the technical aspects of architectures within software engineering but also on the business and or­ ganisational implications of these approaches. Independentlyof how we may answer the question "Is architecture or component technology the new 'silver bullet'?" we must recognise that an approach based on the techniques presented in this book is a long term investment and requires changes in organisation and a careful consideration ofbusiness implications to be successful.

1. An Introduction and History of Software Architectures, Components, and Reuse.- 1.1 Introduction.- 1.2 Software Architecture.- 1.3 Reusable Components.- 1.4 Setting a Context for Component Reuse.- 1.5 Components and How to Use Them.- 1.6 Current and Future Developments.- 2. Components, Scripts and Glue.- 2.1 Introduction.- 2.2 Motivation and State-of-the-Art.- 2.3 A Conceptual Framework for Software Composition.- 2.4 PICCOLA ? a Small Composition Language.- 2.5 Discussion.- 2.6 Conclusions.- 3. Business Component Development.- 3.1 Introduction.- 3.2 Business Component Concepts.- 3.3 Business Component Run-time Concerns.- 3.4 Business Component Development Process Concerns.- 3.5 Summary.- 4. Designing Component Kits and Architectures with Catalysis.- 4.1 Introduction.- 4.2 What is a Component?.- 4.3 Families of Products from Kits of Components.- 4.4 Catalysis: Modelling Component Behaviour.- 4.5 Modelling for Component-Based Development.- 4.6 Summary.- 5. Reuse Requires Architecture.- 5.1 Introduction.- 5.2 What do we Mean by Software Architecture?.- 5.3 Case Study in Reuse ? Matra Cap C3 Systems.- 5.4 Architecture-Based Reuse.- 5.5 Organisation and Technology.- 5.6 Managing the Technology.- 5.7 Components and Reuse.- 5.8 Summary.- 6. Designing Software Architectures Through Evaluation and Transformation.- 6.1 Introduction.- 6.2 Requirements Terminology.- 6.3 Example.- 6.4 Overview of the Method.- 6.5 Functionality-Based Architectural Design.- 6.6Assessing Quality Attributes.- 6.7 Architecture Transformation.- 6.8 Related Work.- 6.9 Conclusions.- 7. An Architecture for Internet Business Applications with Business Components.- 7.1 Introduction.- 7.2 Example.- 7.3 Database Access.- 7.4 A One-Layer Two-Tier Internet Business Application Architecture.- 7.5 Vision forInternet Business Applications.- 7.6 Internet Object Server for Business Entities with RMI.- 7.7 Business Entities Versus Business Processes.- 7.8 Five-Layer Architecture.- 7.9 Providing Layers of Business Objects as Components.- 7.10 Business Components.- 7.11 Conclusions.- 7.12 Acknowledgments.- 8. Lean Product-Line Architectures for Client-Server Systems – Concepts & Experience.- 8.1 Introduction.- 8.2 The CACS System: an End User Perspective.- 8.3 Rearchitecting Client-Server Systems.- 8.4 Framework Technology and Reflection as a Basis of Self-Configuring Product-Line Architectures.- 8.5 A Sample Framelet Family.- 8.6 Discussion and Conclusions.- 9. Issues in Industrial Product-Line Architectures.- 9.1 Introduction.- 9.2 The Case Study.- 9.3 Product-Line Architectures and Reusable Assets.- 9.4 Issues in Product-Line Architectures.- 9.5 Related Work.- 9.6 Conclusion.- 10. Architectural Standards, Processes and Patterns for Enterprise Systems.- 10.1 Today’s Enterprises Face Increasing Competitive Challenges.- 10.2 Distributed Components Offer a Route Forward.- 10.3 “Reuse” Really Means Achieving Economies of Scale.- 10.4 A Component-Capable Organisation Must be Mature.- 10.5 There are Several Synergistic Standards for Enterprise Components...- 10.6 Enterprise Components Require a New Generation of Middleware.- 10.7 Architecture Patterns are Encapsulated Solutions to the Distributed Application Design Problem.- 10.8 Conclusion.- 11. How Not to Reinvent Some Wheels: Lessons from Interactive System Architectures.- 11.1 Lessons from Another Place.- 11.2 Boxes and Arrows are Not Enough.- 11.3 Properties, Not Topologies.- 11.4 Domain Decompositions are Essential.- 11.5 Interactions Between Quality Attributes and Software Architectures.- 11.6 Trade-Offs areUnavoidable.- 11.7 Tools are Essential, but Virtually No Good Ones Exist.- 11.8 Conclusions.- 11.9 Acknowledgements.- 12. An Industrial Perspective.- 12.1 The Current Situation.- 12.2 Architectural Approaches to Software Engineering in Industry.- 12.3 Software Architectures and Component Engineering in Philips.