1. February 19, 2016 1 February 19, 2016February 19, 2016February 19, 2016 Azusa, CA Sheldon X. Liang Ph. D. Software Engineering in CS at APU Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ CS 470 Software Engineering I

2. February 19, 2016 2 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU CS 470 SE-1-2-3

3. February 19, 2016 3 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU One Goal: Flexible Manufacturing Two Elements : Data and Process Three -abilities : Reuse, Extend, and Flexible SE-1-2-3: Software Design & Implementation

4. February 19, 2016 4 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU SE-1-2-3: Software Design & Implementation We’re poor learners from industrial manufacturing Logical product Hard to repeat Hard to specify Hard of hard

5. February 19, 2016 5 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU SE-1-2-3: Software Design & Implementation We face simple issues but struggle a lot Niklaus Wirth, Author of PASCAL Program = ????

6. February 19, 2016 6 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU SE-1-2-3: Software Design & Implementation We’re smart to convert software into hardware --> OO strategy

7. February 19, 2016 7 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU SE-1-2-3: Software Design & Implementation We’re pursuing three -abilities

8. February 19, 2016 8 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU SE-1-2-3: Software Design & Implementation How to do by digging in more depth

9. February 19, 2016 9 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU SE-1-2-3: Software Design & Implementation A - Abstract D - Data T - Type

10. February 19, 2016 10 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU SE-1-2-3: Software Design & Implementation A - Abstract D - Data T - Type

11. February 19, 2016 11 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU SE-1-2-3: Software Design & Implementation ADT - A model for the problem to be solved ADT - Described by its properties ADT - Generalized by specifying type ADT - Simulated by OOP Code Construction: Modularity

12. Thank you very much! Questions? February 19, 2016 12 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU SE-1-2-3: Software Design & Implementation

13. February 19, 2016 13 February 19, 2016February 19, 2016February 19, 2016 Azusa, CA Sheldon X. Liang Ph. D. Software Engineering in CS at APU Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ CS 470 Software Engineering I

14. February 19, 2016 14 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU CS 470 Design Engineering

15. February 19, 2016 15 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU CS 470 Design Engineering

16. February 19, 2016 16 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU CS 470 Design Engineering Design and Quality the design must implement all of the explicit requirements contained in the analysis model, and it must accommodate all of the implicit requirements desired by the customer. the design must be a readable, understandable guide for those who generate code and for those who test and subsequently support the software. the design should provide a complete picture of the software, addressing the data, functional, and behavioral domains from an implementation perspective.

17. February 19, 2016 17 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU CS 470 Design Engineering Design Principles The design process should not suffer from ‘tunnel vision.’ The design should be traceable to the analysis model. The design should not reinvent the wheel. The design should “minimize the intellectual distance” [DAV95] between the software and the problem as it exists in the real world. The design should exhibit uniformity and integration. The design should be structured to accommodate change. The design should be structured to degrade gently, even when aberrant data, events, or operating conditions are encountered. Design is not coding, coding is not design. The design should be assessed for quality as it is being created, not after the fact. The design should be reviewed to minimize conceptual (semantic) errors.

18. February 19, 2016 18 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU CS 470 Design Engineering Fundamental Concepts abstraction—data, procedure, control architecture—the overall structure of the software patterns—”conveys the essence” of a proven design solution modularity—compartmentalization of data and function hiding—controlled interfaces Functional independence—single-minded function and low coupling refinement—elaboration of detail for all abstractions Refactoring—a reorganization technique that simplifies the design

19. February 19, 2016 19 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU CS 470 Design Engineering Information Hiding module controlled interface "secret" algorithm algorithm data structure data structure details of external interface details of external interface resource allocation policy resource allocation policy clients a specific design decision

20. February 19, 2016 20 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU CS 470 Design Engineering Why Information Hiding? reduces the likelihood of “side effects” limits the global impact of local design decisions emphasizes communication through controlled interfaces discourages the use of global data leads to encapsulation—an attribute of high quality design results in higher quality software

21. February 19, 2016 21 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU CS 470 Design Engineering Stepwise Refinement open walk to door; reach for knob; open door; walk through; close door. repeat until door opens turn knob clockwise; if knob doesn't turn, then take key out; find correct key; insert in lock; endif pull/push door move out of way; end repeat

22. February 19, 2016 22 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU CS 470 Design Engineering Functional Independence

23. February 19, 2016 23 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU CS 470 Design Engineering The Design Model

24. February 19, 2016 24 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU CS 470 Design Engineering Design Model Elements Data elements –Data model --> data structures –Data model --> database architecture Architectural elements –Application domain –Analysis classes, their relationships, collaborations and behaviors are transformed into design realizations –Patterns and “styles” (Chapter 10) Interface elements –the user interface (UI) – external interfaces to other systems, devices, networks or other producers or consumers of information – internal interfaces between various design components. Component elements Deployment elements

25. February 19, 2016 25 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU CS 470 Design Engineering Design Patterns The best designers in any field have an uncanny ability to see patterns that characterize a problem and corresponding patterns that can be combined to create a solution A description of a design pattern may also consider a set of design forces. –Design forces describe non-functional requirements (e.g., ease of maintainability, portability) associated the software for which the pattern is to be applied. The pattern characteristics (classes, responsibilities, and collaborations) indicate the attributes of the design that may be adjusted to enable the pattern to accommodate a variety of problems.

26. February 19, 2016 26 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU CS 470 Design Engineering Frameworks A framework is not an architectural pattern, but rather a skeleton with a collection of “plug points” (also called hooks and slots) that enable it to be adapted to a specific problem domain. Gamma et al note that: –Design patterns are more abstract than frameworks. –Design patterns are smaller architectural elements than frameworks –Design patterns are less specialized than frameworks

27. Thank you very much! Questions? February 19, 2016 27 Azusa Pacific University, Azusa, CA 91702, Tel: (800) 825-5278 Department of Computer Science, http://www.apu.edu/clas/computerscience/http://www.apu.edu/clas/computerscience/ Software Engineering in CS at APU CS 470 Design Engineering