1. Page 1 Building Reliable Component-based Systems Chapter 19 - Industrial Experience with Dassault Système Component Model Chapter 19 Industrial Experience with Dassault Système Component Model

2. Page 2 Building Reliable Component-based Systems Chapter 19 - Industrial Experience with Dassault Système Component Model Overview qIntroduction qThe OM Component Model qDiscussion qLessons Learned

3. Page 3 Building Reliable Component-based Systems Chapter 19 - Industrial Experience with Dassault Système Component Model Introduction q CATIA l Dassault Systèmes main software product l 5 millions lines of code l 19 000 clients l 180 000 work places l 50000 C++ classes l 8000 components l Object Modeller: Own component model

4. Page 4 Building Reliable Component-based Systems Chapter 19 - Industrial Experience with Dassault Système Component Model Dassault Systèmes q The DS objective was not primarily: l To sell isolated OM components. l To sell the OM component framework. l To make their component model a standard. q The primary objective was: l To find a way to develop its software under the best conditions, and to provide to its customers with powerful adaptability facilities.

5. Page 5 Building Reliable Component-based Systems Chapter 19 - Industrial Experience with Dassault Système Component Model The OM Component Model q The OM is quite similar to COM. qInterfaces: a set of method signatures l Component may support more than one interface.

6. Page 6 Building Reliable Component-based Systems Chapter 19 - Industrial Experience with Dassault Système Component Model External view of OM components (a) External view of an OM component Interfaces (b) Heterogeneous application Other software entities OM components Dependencies

7. Page 7 Building Reliable Component-based Systems Chapter 19 - Industrial Experience with Dassault Système Component Model Using OM Components to Build Applications q In practice, there is no boundary between traditional development and component-based development. l DS applications are hybrids. l There is a Lack of support for explicit connections and assembly facilities. l DS does not aim to sell components, but extensible applications.

8. Page 8 Building Reliable Component-based Systems Chapter 19 - Industrial Experience with Dassault Système Component Model Component implementation Component inheritance Bases Extensions c c ? ? Interfaces Component implementation Delegation

9. Page 9 Building Reliable Component-based Systems Chapter 19 - Industrial Experience with Dassault Système Component Model Implementations qDS components are typically developed by different teams in different companies. qComponents are in fact a collection of elementary pieces of code, called implementations.

10. Page 10 Building Reliable Component-based Systems Chapter 19 - Industrial Experience with Dassault Système Component Model Extensions q Has two kinds of implementations: l Base implementations and extensions. l A component is defined by a base implementation. q An extension has two advantageous properties: l It does not change the identity of the component being extended. l It does not change the code of the component being extended

11. Page 11 Building Reliable Component-based Systems Chapter 19 - Industrial Experience with Dassault Système Component Model Component inheritance qSingle inheritance qInherits all its interfaces and all its implementations.

12. Page 12 Building Reliable Component-based Systems Chapter 19 - Industrial Experience with Dassault Système Component Model Conditional interfaces qThe interface will be returned to the client only if this expression evaluates to true. l 2D or 3D

13. Page 13 Building Reliable Component-based Systems Chapter 19 - Industrial Experience with Dassault Système Component Model Discussion q Has not develop a new language: l The OM can be seen as a layer superimposed on the C++ language. l Interfaces and implementations are represented as C++ classes. l OM constructions are indeed represented as code patterns and macros in C++ source code.

14. Page 14 Building Reliable Component-based Systems Chapter 19 - Industrial Experience with Dassault Système Component Model Different Kinds of Architecture (a) Physical architecture(b) OM components vs. frameworks Frameworks Dependency OM elements Other entities

15. Page 15 Building Reliable Component-based Systems Chapter 19 - Industrial Experience with Dassault Système Component Model Framework Evolution q A good component framework: l Satisfies development / maintenance needs. l Is easily mastered and understood by developers. q It is incorrect to believe that if a concept is simple, its use will also be simple: l “goto” and pointers l AddRef and Release

16. Page 16 Building Reliable Component-based Systems Chapter 19 - Industrial Experience with Dassault Système Component Model Evolution q An incremental process. l Model evolved permanently while CATIA software was in development. l Required different concepts and constructs to coexist, which created problems. q A bug may be due to: l Faulty implementation of the concept, l Undefined semantic hole l Inherent complexity. Specific training courses should be employed to ensure the correct use of the component model.

17. Page 17 Building Reliable Component-based Systems Chapter 19 - Industrial Experience with Dassault Système Component Model Industrial Perspective q Should Connectors be regarded as first class citizens? q Reexamination of the definitions of: l Connectors l Behavior l Architecture l Components

18. Page 18 Building Reliable Component-based Systems Chapter 19 - Industrial Experience with Dassault Système Component Model Summary qThe design of a powerful component model is shown to be a complex task. q The model has improved progressively over the years. q Very large systems must live with inconsistencies. l Training is needed to prevent misuse. l Tools for tracking invalid constructions. We have still to invent the CBSE environments of the future.