1. Requirements Specification Copyright, 2001 © Jerzy R. Nawrocki Jerzy.Nawrocki@put.poznan.pl www.cs.put.poznan.pl/jnawrocki/mse/require/ Requirements Engineering Lecture 5 Requirements Engineering Lecture 5

2. J. Nawrocki, Requirements Eng. (5) Plan of the lecture McCall’s quality factors Operating environment Metaphor of the system System’s functionality Standard traced-from relation

3. J. Nawrocki, Requirements Eng. (5) McCalls Quality Factors Max speed? Fuel consumption?

4. J. Nawrocki, Requirements Eng. (5) McCalls Quality Factors Max speed > 150 km/h Fuel consumption < 5 l/100 Golden fish

5. J. Nawrocki, Requirements Eng. (5) McCalls Quality Factors Correctness – tst Reliability (precision, accuracy) – tst Efficiency – tst Integrity (security) – tst Usability ? Maintainability – insp Flexibility ? Testability ? Portability (interoperability) – spec Reusability x

6. J. Nawrocki, Requirements Eng. (5) McCalls Quality Factors Communication commonality ? Completeness – tst report Conciseness ? Consistency – doc c.: audits Data commonality ? Error tolerance ? Instrumentation – spec + tst Security – tst Self documentation: spec?, audits

7. J. Nawrocki, Requirements Eng. (5) Plan of the lecture McCall’s quality factors Operating environment Metaphor of the system System’s functionality Standard traced-from relation

8. J. Nawrocki, Requirements Eng. (5) Operating environment End user Device External system The system ENV1ENV2

9. J. Nawrocki, Requirements Eng. (5) Operating environment ENV1: End users The system will be used by the following people: Chief accountant President Sales director All the end users

10. J. Nawrocki, Requirements Eng. (5) All the external devices and systems Operating environment ENV2: External devices and systems The system will communicate with the following external devices and systems: SAP R/3

11. J. Nawrocki, Requirements Eng. (5) Operating environment End user The system

12. J. Nawrocki, Requirements Eng. (5) Operating environment ENV3: Chief accountant’s operations The chief accountant can initiate the following operations: Taking an invoice... All the operations user, device, or external sys.

13. J. Nawrocki, Requirements Eng. (5) Plan of the lecture McCall’s quality factors Operating environment Metaphor of the system System’s functionality Standard traced-from relation

14. J. Nawrocki, Requirements Eng. (5) Metaphor of the system The system Consumer Producer How to specify taking an invoice?

15. J. Nawrocki, Requirements Eng. (5) Metaphor of the system The system Invoice buffor What do I have to know about the system to specify its operations?

16. J. Nawrocki, Requirements Eng. (5) Metaphor of the system MET1: Internal architecture The system will consist of the following elements: Invoice buffor (empty or non- empty)... All the elements and states

17. J. Nawrocki, Requirements Eng. (5) Plan of the lecture McCall’s quality factors Operating environment Metaphor of the system System’s functionality Standard traced-from relation

18. J. Nawrocki, Requirements Eng. (5) System’s Functionality STOP 0.1234 Function (Operation) Not now! Precision ? Side effect Input Output

19. J. Nawrocki, Requirements Eng. (5) System’s Functionality STOP 0.12 Function (Operation) Input Output First.. Then..

20. J. Nawrocki, Requirements Eng. (5) System’s Functionality FUN1: Taking an invoice INPUT: - CONDITION: The invoice buffer is nonempty. OUTPUT: An invoice (pattern IP-1/99.09) SIDE EFFECT: The taken invoice is removed from the buffer. If it is the only invoice in the buffer, the buffer gets empty. PROCESSING: - PRECISION: The fraction part of each amount is represented with two digits.

21. J. Nawrocki, Requirements Eng. (5) Plan of the lecture McCall’s quality factors Operating environment Metaphor of the system System’s functionality Standard traced-from relation

22. J. Nawrocki, Requirements Eng. (5) Standard traced-from relation ENV1 ENV2 Dev MET1 ENV3ENVm FUN1 Dev ENVm+1 FUNx

23. J. Nawrocki, Requirements Eng. (5) SummarySummary McCall’s quality factors Operating environment Metaphor of the system System’s functionality Standard traced-from relation

24. J. Nawrocki, Requirements Eng. (5) Further readings  I. Sommerville, P. Sawyer, Requirements Engineering, John Wiley & Sons, Chichester, 1997 Using Rational RequisitePro, Chapter 10 (Working with Traceability), 147-149.

25. J. Nawrocki, Requirements Eng. (5) HomeworkHomework Create your „Functional Requirements” document.

26. J. Nawrocki, Requirements Eng. (5) Quality assessment 1. What is your general impression? (1 - 6) 2. Was it too slow or too fast? 3. What important did you learn during the lecture? 4. What to improve and how?