Extreme Programming

1
Extreme Programming

• Simplicity
• Communication
• Feedback
• Courage

2
Simplicity

• The simplest thing that will possibly work.
• Q, How to decide what works?
• Unit tests!

3
Test-driven Development

• Start with a few tests
• Write the simplest code that passes those tests
• If you arent satisfied that your does everything
  you want it to
• Write more tests and repeat.

4
Communication

• Programming projects are living entities.
• Their life depends on the continuity of the
  development group
• Group continuity more valuable than the code!
• The development group must pass on knowledge of
  the system.

5
DrJava as Living Software

• Summer projects.
• Masters theses.
• Comp 312.

6
Communication in the DrJavaProject

• Pair programming as teaching
• Onsite customer Corky, students (you)
• Labs
• Team meetings

7
The SourceForge Website

• Bug reports
• Feature requests
• From around the world

8
Feedback

• Unit tests
• Unit tests
• Unit tests
• Code walks
• Pair programming as continual code walk
• SourceForge

9
Courage

• Desirable characteristics of a developer
• Aptitude
• Competence
• Integrity

10
Courage

• Dont hide what you dont know
• Dont hide what you cant do
• Dont hide how long you thing it should take
• Dont hide what you havent done

11
Extreme Programming and Specifying Software

• Old approach monolithic specifications
• Never right
• Nobody understands it all
• Takes too long

12
Implementation as Specification?

• An implementation specifies what is does
• Why not just use the implementation?

13
Stories as Incremental Specification

• Stories are short, concrete examples describing
  how the systems should behave.
• Stories are informal (in English).
• Stories should be as independent as possible.

14
DrJava Stories and SourceForge

• DrJava stories are maintained on the SourceForge
  website as feature requests
• Always write feature requests as stories.
• When implemented, stories are broken into tasks.
• Each task should take no longer than one
  pair-week.

15
Example Story

• Simple JUnit integration
• The user has open a JUnit TestCase in the
  Definitions pane. He clicks on a "Test" button on
  the toolbar, and JUnit is run over this TestCase.
  Some indication of progress is presented while
  JUnit is running.
• The results are output to a new tabbed pane in
  the Interactions window. The user can click on
  the reported errors and the corresponding test
  case (perhaps the individual assertion) is
  highlighted.