Agile Software Development Chapter 3

Chapter 3 - Agile Software Development

• Rapid software development is becoming increasingly important as businesses operate in fast-changing environments.
  • Agile methods, such as Extreme Programming (XP), are used to quickly respond to changing business needs.
  • Agile development involves rapid and flexible response to change, with an emphasis on delivering working software in short iterations.

Agile Methods

• Agile methods prioritize individuals and interactions, working software, customer collaboration, and responding to change.
  • Agile manifesto: "We value individuals and interactions over processes and tools, working software over comprehensive documentation, customer collaboration over contract negotiation, and responding to change over following a plan."

Principles of Agile Methods

• Customer involvement: Customers are closely involved throughout the development process to provide and prioritize new system requirements and evaluate iterations.
  • Incremental delivery: Software is developed in increments, with customers specifying requirements for each increment.
  • People not process: Team members are left to develop their own ways of working without prescriptive processes.
  • Embrace change: Expect system requirements to change, and design the system to accommodate these changes.
  • Maintain simplicity: Focus on simplicity in both the software and the development process.

Agile Method Applicability

• Agile methods are suitable for:
  • Product development where a software company is developing a small or medium-sized product for sale.
  • Custom system development within an organization where there is a clear commitment from the customer to become involved in the development process.

Extreme Programming (XP)

• XP is an agile method that integrates good programming practices, such as:
  • Incremental planning: Requirements are recorded on story cards, and the stories to be included in a release are determined by the time available and their relative priority.
  • Small releases: The minimal useful set of functionality that provides business value is developed first, with frequent releases that incrementally add functionality.
  • Simple design: Enough design is carried out to meet current requirements, and no more.
  • Test-first development: Automated unit tests are written for new functionality before that functionality is implemented.
  • Refactoring: Code is continuously refactored to keep it simple and maintainable.

XP Practices

• Refactoring: Making small, incremental changes to the code to improve its structure and simplicity while preserving its functionality.
  • Pair programming: Programmers work in pairs, with each pair working together at the same workstation to develop the software.

Scrum

• Scrum is a general agile method that focuses on managing iterative development rather than specific agile practices.
  • Scrum involves an outline planning phase, a series of sprint cycles, and a project closure phase.
  • Sprints are fixed-length (usually 2-4 weeks) and correspond to the development of a release of the system.

Scaling Agile Methods

• Scaling up: Using agile methods for developing large software systems that cannot be developed by a small team.
  • Scaling out: Introducing agile methods across a large organization with many years of software development experience.
  • Scaling agile methods involves maintaining agile fundamentals, such as flexible planning, frequent system releases, continuous integration, test-driven development, and good team communications.