Software Engineering

1. Software Engineering General architecture

2. General architecture • Architectural components: • Program organisation overview • Major building blocks in a system • Definition of each building block’s area of responsibility • A building block should know as little as possible about other building blocks’ areas of responsibility • Communication rules for each building block should be well defined

3. General architecture • Major classes • Responsibilities of each major class • Interaction with other classes • Class hierarchies • State transitions • Object persistence • Organisation of classes in subsystems

4. General architecture • Data design • Major files and table designs to be used • Access policies (sequential, direct, etc.) • Storage policies • High-level organisation and contents of data and databases • Typically, data should be accessed directly by only one class or subsystem

5. General architecture • Business rules • Using the terminology of General Systems Theory, environmental rules that affect the behaviour of the system

6. General architecture • User interface design • Interface paradigm(s) • Architecture should be such that interface could be replaced without affecting other parts of the system

7. General architecture • Resource management • Database connections • Threads • Handles • Memory

8. General architecture • Security • Manipulation of buffers • Rules for handling untrusted data • Encryption • Level of detail contained in error messages • Protection of data in memory

9. General architecture • Performance issues • Performance goals • Performance bottlenecks • Scalability • Interoperability

10. General architecture • Internationalisation / localisation • Obs: issue of growing importance nowadays • Input / Output • I/O policy (look ahead, look behind, just in time) • I/O error detection level (field, record, stream, file, etc.)

11. General architecture • Error processing • Corrective versus detective • Active versus passive • Error propagation policy • Conventions for handling error messages • Exception handling policy • At what levels are errors handled? • What is the level of responsibility of each class for validating input data? • Tailor made error processing or use development environment pre-fabricated solutions?

12. General architecture • Fault tolerance • Expected fault tolerance • Fault tolerance strategies • Architectural feasibility • Is proposed design viable, considering available resources and proposed requirements? • Overengineering • How to ensure system level robustness?

13. General architecture • “Buy” or build? • Reuse decisions • Architecture recurring revision strategy

14. General architecture • General architecture quality • How to preserve conceptual integrity • Clearly stated architecture’s objectives • Motivations for all major decisions • Machine- and language-independent architecture • Multiple views • NO COMPROMISING!