1. © 2009 University of California, Irvine – André van der Hoek1February 8, 2009 – 21:49:30 Informatics 122 Software Design II Lecture 9 André van der Hoek & Alex Baker Duplication of course material for any commercial purpose without the explicit written permission of the professor is prohibited.

2. © 2009 University of California, Irvine – André van der Hoek2February 8, 2009 – 21:49:30 Palantír Design Recovery – Debriefing How difficult was this? Why?

3. © 2009 University of California, Irvine – André van der Hoek3February 8, 2009 – 21:49:30 Palantír Design Recovery – Debriefing How difficult was this? Why? More or less difficult than it seemed when you first looked at the code?

4. © 2009 University of California, Irvine – André van der Hoek4February 8, 2009 – 21:49:30 Palantír Design Recovery – Debriefing What strategies did you use?

5. © 2009 University of California, Irvine – André van der Hoek5February 8, 2009 – 21:49:30 Palantír Design Recovery – Debriefing What strategies did you use? Did you… –…run the program (frequently?)‏ –…seek Palantír documentation? –…seek DependencyFinder documentation? –…use any external tools? –…use Eclipse’s search features? –…read code? –… –Did you manage to cover all of the code?

6. © 2009 University of California, Irvine – André van der Hoek6February 8, 2009 – 21:49:30 Palantír Design Recovery – Debriefing Did you need to make any assumptions that guided your explorations? Did those assumptions hold throughout?

7. © 2009 University of California, Irvine – André van der Hoek7February 8, 2009 – 21:49:30 The Design of Palantír How does Palantír work? –a basic architecture –how does it know about user actions? –what is its relationship to Eclipse? –what is its relationship to DependencyFinder?

8. © 2009 University of California, Irvine – André van der Hoek8February 8, 2009 – 21:49:30 The Design of Palantír How does Palantír work? –a basic architecture –how does it know about user actions? –what is its relationship to Eclipse? –what is its relationship to DependencyFinder? Did you have a breakthrough “a-ha” moment in gaining this understanding?

9. © 2009 University of California, Irvine – André van der Hoek9February 8, 2009 – 21:49:30 The Design of Palantír What are the major design decisions behind Palantír?

10. © 2009 University of California, Irvine – André van der Hoek10February 8, 2009 – 21:49:30 The Design of Palantír What are the major design decisions behind Palantír? How do you know?

11. © 2009 University of California, Irvine – André van der Hoek11February 8, 2009 – 21:49:30 The Design of Palantír What are the major design decisions behind Palantír? How do you know? How confident are you that you know?

12. © 2009 University of California, Irvine – André van der Hoek12February 8, 2009 – 21:49:30 Design Critique Was the design easy to understand? –why? –why not?

13. © 2009 University of California, Irvine – André van der Hoek13February 8, 2009 – 21:49:30 Design Critique Was the design easy to understand? –why? –why not? How did naming, package structures, and comments help or hurt understandability? Was it consistent in its organization?

14. © 2009 University of California, Irvine – André van der Hoek14February 8, 2009 – 21:49:30 Design Critique How changeable is Palantír? Would you easily be able to, for example, … –…add a new event? –…allow for other analyses? –…add a new visualization? –…overlay design deviations? –… How easily?

15. © 2009 University of California, Irvine – André van der Hoek15February 8, 2009 – 21:49:30 Design Critique What was the impact of using Eclipse? –positive? –negative?

16. © 2009 University of California, Irvine – André van der Hoek16February 8, 2009 – 21:49:30 Design Critique Do you think Palantír is well-designed? What is its biggest failing, and why? What would you change about its approach?

17. © 2009 University of California, Irvine – André van der Hoek17February 8, 2009 – 21:49:30 The Nature of Software Makes This Difficult Invisibility –we cannot see the designer’s high level picture, obscured in code details Complexity –if users want a program to do 30 different things, then the program must do those 30 different things –can this be done elegantly? Conformity –Eclipse, DependencyFinder, the ways people make changes – all are invisible forces on the way the design is structured Changeability –the Palantír code you see has been changed, can cause problems [Brooks: No Silver Bullet]

18. © 2009 University of California, Irvine – André van der Hoek18February 8, 2009 – 21:49:30 Some Theory Design recovery is a matter of finding the ideas hidden in a bunch of code The implementer has some responsibility, code can ruin a good design Metaphor, architecture, organization, naming, and program flow design can go a long way to controlling and communicating this

19. © 2009 University of California, Irvine – André van der Hoek19February 8, 2009 – 21:49:30 Feedback Did you learn about software design from this? –how understandable are your designs? –what plays into understandability? How did the team dynamic help or hinder your work?

20. © 2009 University of California, Irvine – André van der Hoek20February 8, 2009 – 21:49:30 Assignment 4 – Design Patterns Improve the design of Palantír by replacing existing structures in the UML model with appropriate patterns –start with any of the designs available to your group You should apply at least 5 different design patterns –at least two not discussed in class Each use of a pattern should be carefully motivated in a brief accompanying document

21. © 2009 University of California, Irvine – André van der Hoek21February 8, 2009 – 21:49:30 Assignment 4 – Design Patterns Each group must turn in: –the original UML diagram from which you started –a new UML diagram, with each pattern precisely highlighted as to where it resides in the UML diagram –a document describing  the motivation for each pattern  the impact the application of the pattern has on the original design (i.e., how far reaching is the change to incorporate the pattern?)‏ –graded on usefulness of the pattern, diversity of patterns, rationale, and level of design understanding Each person also needs to submit a team evaluation (new forms available on class webpage)‏ E-mail copy due Monday, February 21 st, 4pm –e-mail to André, Alex, and Kyle

22. © 2009 University of California, Irvine – André van der Hoek22February 8, 2009 – 21:49:30 Further Tips Read the book Discuss the patterns with each other Imagine possible changes against which you would like to insulate Try different parts of the code Use the UML

23. © 2009 University of California, Irvine – André van der Hoek23February 8, 2009 – 21:49:30 Team Assignments Team 1 Tomas Ruiz-Lopez Lance Zepeda Matt Fritz Scott Roeder Leslie Liu Team 2 Lance Cacho Robert Jolly Alton Chislom Alexander Doan Alex Kaiser Team 3 Daniel Morgan Aylwin Villanueva Robert Duncan Jordan Sinclair Chad Curtis Team 4 Scott Ditch Jay Bacuetes James Rose Rakesh Rajput Ben Kahn Team 5 Joshua Villamarzo James Milewski Jeffrey Gaskill Matt Shigekawa David Schramm Derek Lee