Extreme Programming Mark Steverson

What Is Extreme Programming? ● Extreme Programming (XP) is a lightweight, agile methodology developed by Kent Beck ● Designed to work with projects that can be built by teams of two to ten programmers,that aren't sharply constrained by the existing computing environment, and where executing tests can be done in a fraction of the day ● XP contains four values at its core: Communication, Simplicity, Feedback, and Courage ● Five Basic Principles: Rapid Feedback, Assume Simplicity, Incremental Change, Embracing Change, Quality Work

Practices of Extreme Programming ● The Planning Game – Determine the scope of the next release by looking at business priorities and technical estimates ● Small Releases – Release simple versions of the system often ● Metaphor – A story of how the system works, the architecture ● Simple Design – System should be designed as simply as possible at any given moment ● Testing – Test constantly, all tests must run flawlessly to continue development. ● Refactoring – Programmers can restructure the system at any time without changing behaviour to simplify, remove duplication, or add flexibility

Practices Continued ● Pair Programming – All code is written by two programmers using one machine ● Collective Ownership – Everyone owns the code and can modify it at any time ● Continuous Integration – Every time a task is completed it should be integrated and tested, integration should take place many times a day ● 40-Hour Week – Only work 40 hours a week, no overtime for two weeks in a row ● On-Site Customer – A person who will be using the system on call at all time to answer questions. ● Coding Standards - Code is written in a standard way by all programmers to improve communication

Where Will XP not work? ● Anytime you are using a technology with an inherently exponential cost curve. ● An environment where it takes a long time to gain feedback ● Any place where the physical environment is not suited for communication ● XP will not work well with a large amount of people