eXtreme Programming (XP)

Definition

eXtreme Programming (XP) is a lightweight software development method that, like RDD, has its origins in the Smalltalk community. XP was developed by Kent Beck, Ward Cunningham, Martin Fowler, Ralph Johnson, Ron Jeffries, and others within the XP community.

Values

XP emphasizes the following values:

• Communication (verbal person-to-person communication)
• Simplicity (implementing "the simplest thing that could possibly work")
• Feedback (from the system via a test case)
• Courage (to refactor)
• Respect (collective ownership)

Principles

XP recommends the following principles:

• Rapid Feedback (via automated testing of partial executable application)
• Incremental Change
• Embrace Change
• Quality Work

Activities

XP recommends the following XP activities:

• Coding
• Testing
• Listening
• Designing

Techniques

XP recommends the following techniques:

• The Planning Game
• Frequent Releases
• System Metaphor
• Simple Design
• Unit Tests and Function Tests
• Refactor Mercilessly
• Pair Programming
• Collective Code Ownership
• Continuous Integration
• Fourty Hour Week
• On-Site Customer
• Coding Standards

XP in OPF

OPF incorporates the following XP practices as OPF techniques for performing tasks withing the following OPF activities:

• Project Management:
  • The Scheduling Game
• Requirements Engineering:
  • On-Site Customer (OPF Customer, User)
  • Use Case Cards for requirements elicitation
  • Collective Requirements Ownership
• Design:
  • Refactoring
  • Collective Design Ownership
• Implementation:
  • Coding Standards
  • Collective Code Ownership
  • Pair Programming
  • Refactoring
• Integration:
  • Frequent Releases (builds)
  • Continuous Integration
• Testing:
  • Collective Test Ownership
  • Unit Test and Function Tests (Testing First, Automated Testing)

Weaknesses

XP has the following weaknesses, some of which are quite contraversial:

• Very informal requirements
• Very minimal and informal architecture
• Lack of formal documentation
• Weakness with regard to testing techniques
• Heavy emphsis on making every developer a programmer who is part of a pair programming team (i.e., there are very few separate roles and teams).
• Lack of defined process
• Lack of support for reuse
• Limited team size (less than 10 people per project)
• Because XP is restricted to software development, it does not address:
  • Systems developement
  • Application delivery
  • Business modeling (business, branding, and technology strategy)

More Information

More information can be found at:

• Wiki Web
• XP Organization