Design Recovery

Today’s Lecture Reverse engineering Assignment 3 Benumbered design continued (if time)

Reverse Engineering Recreating design abstractions from:  Code  Existing design documentation (if available)  Personal experience / general knowledge about problem and application domains  Talking to people (Biggerstaff, 1989)

Design Recovery We might need  Formal specifications  Dataflows  Underlying patterns  Informal knowledge We want to understand  What  How  Why This might be more than just re-creating…

Why do we have to do this?

Working with others’ code…  Debugging  Maintenance  Modification  Reuse Working with your own code You will work with code in the absence of a complete design

Why do we have to do this? No design  Lost design  Build-and-fixed  Agile methodologies Design drift  Common! Incomprehensible design

Design Recovery’s Goals Recover lost information Cope with complexity Generate alternate views Detect side effects Facilitate Reuse (Chikofsky and Cross, 1990)

Design Recovery Tips

Object Orientation Something of an advantage  Class names, function names  Established relationships (inheritance, members, etc.) High cohesion helps  A holistic sense of purpose

Finding the structure Entities  Classes  Methods  Variables Relationships  Inheritance  Member Objects  Method calls

Approaches Reverse engineering tools  E.g. Omondo Running the program Eclipse’s References and Declarations Reading documentation Reading class names Talking to people Code reading

Also, remember Existing artifacts, but also  Personal experience  Knowledge about problem  Knowledge about the context  Knowledge about solution

A (Small) Example addAllPixels(Image image){ for(int i = 0; i < image.getWidth(); i++){ for(int j = 0; j < image.getHeight(); j++){ Color c = image.getColor(i, j); addPixel(new Pixel(i, j, c)); addToColumn(i, new Pixel(i, j, c)); updateColorTotals(c); }}}

We might be able to guess that: Need for a pixel class Different instances for  addPixel  addToColumn Concerned about speed  Not so much about space Concerned about changability?  Or just following convention

Could have just been addAllValues(ImageNumber n){ for(int i = 0; i < image.height; i++){ for(int j = 0; j < image.height; j++){ colorArray[n][i][j] = image.colorAt(i, j); }}}

Assignment 3 – Design Recovery Recover the design of Calico (surprise!)  Tool for electronic whiteboard software design developed at UC Irvine  You may use any tools you like  Do not ask anyone about it (despite that normally being a good resource) Get the Calico code from the subversion repository, detailed instructions follow

Assignment 3 – Design Recovery Each group must turn in:  A complete UML (-ish) Diagram  At least 1 additional diagram of your choice (might be informal)‏  A document describing the design of Calico (at least 4 pages)‏  Your audience is someone unfamiliar with Calico who needs to make very significant changes to it  The code may not compile  Your submission graded on completeness, clarity, accuracy Each person also needs to submit a team evaluation (forms available on class webpage)‏ Paper copy due Thursday, February 4 th, at start of class

Suggestions for Group Work Everyone start by taking their own look at the whole system  Multiple perspectives will be very useful Work out the high level architecture Understand program flows Look out for subtle details

Further tips There are papers available on Calico on André's website; feel free to consult them Use representations of classes to organize Rote completeness is not the answer, will need to be elegant

Team Assignments Team 1 Warren Applebaum Stacey Dao Sam Kaufman Kyle Lutze Ryan Nissenbaum Team 2 James Benson Hunter Gillane Garrett Kim Francesco Mantovani Hiroe Ono Team 3 Alex Chung Sohrab Hejazi Tae Kim Michael Merchant Matthew Palmer Team 4 Andrew Ziming Ryan Hsu Frank Morales Joshua Papa Jordaniel Wolk Team 5 Jessie Danielson Simon Huynh Patrick Lu Kyle Musler Sean Tsusaki Leo Zen

Detailed Checkout Instructions Two Steps: 1) Install Subclipse plugin for Eclipse 2) Check out the Calico repository NB: this assumes that you're using Eclipse and are otherwise comfortable with it.

Detailed Checkout Instructions 1. In Eclipse, go to Help > Software Updates > “Available Software” tab

Detailed Checkout Instructions 2. Hit “add site”, enter location:

Detailed Checkout Instructions 3. Hit “OK” => Check the Subclipse main box => hit “Install”

Detailed Checkout Instructions 4. Make sure everything is checked off and hit “Finish”

Detailed Checkout Instructions 5. Let the libraries download => hit “Yes” at this dialogue box

Detailed Checkout Instructions 6. Make a new Project (NOT Java Project) and choose this

Detailed Checkout Instructions 7. Make a new repository location

Detailed Checkout Instructions 8. Enter and hit “next”

Detailed Checkout Instructions 9. Select the root of the tree => hit “Next” (NOT “Finish”)‏

Detailed Checkout Instructions 10. Check out in the workspace => give it a name => hit “Finish”

Server Checkout To checkout the server version, you will need to repeat steps 6 through 10. Just replace the SVN URL with: Note: You will need to login with your ICS username and password. (If you receive any SSL certificate errors, you can safely ignore them) If you have any problems, please feel free to or stop by my office (ICS2 room 110)