Agile Software Development
What is Agile Software Development Methodology?
Agile development practices increase the velocity at which software teams deliver customer value by improving everyone’s visibility into project features, quality and status.
Agile software development refers to a group of software development methodologies based on iterative development, where requirements and solutions evolve through collaboration between self-organizing cross-functional teams.
Agile methods generally promote a disciplined project management process that encourages frequent inspection and adaptation, a leadership philosophy that encourages teamwork, self-organization and accountability, a set of engineering best practices intended to allow for rapid delivery of high-quality software, and a business approach that aligns development with customer needs and company goals.
There are many specific agile development methods. Most promote development, teamwork, collaboration, and process adaptability throughout the life-cycle of the project.
Agile methods break tasks into small increments with minimal planning, and do not directly involve long-term planning. Iterations are short time frames that typically last from one to four weeks. Each iteration involves a team working through a full software development cycle including planning, requirements analysis, design, coding, unit testing, and acceptance testing.
This helps minimize overall risk, and lets the project adapt to changes quickly. Stakeholders produce documentation as required. An iteration may not add enough functionality to warrant a market release, but the goal is to have an available release (with minimal bugs) at the end of each iteration. Multiple iterations may be required to release a product or new features.
Team composition in an agile project is usually cross-functional and self-organizing without consideration for any existing corporate hierarchy or the corporate roles of team members. Team members normally take responsibility for tasks that deliver the functionality an iteration requires. They decide individually how to meet an iteration’s requirements.
Agile methods emphasize face-to-face communication over written documents when the team is all in the same location. When a team works in different locations, they maintain daily contact through videoconferencing, voice, e-mail, etc.
Most agile teams work in a single open office (called bullpen), which facilitates such communication. Team size is typically small (5-9 people) to help make team communication and team collaboration easier. Larger development efforts may be delivered by multiple teams working toward a common goal or different parts of an effort. This may also require a coordination of priorities across teams.
No matter what development disciplines are required, each agile team will contain a customer representative. This person is appointed by stakeholders to act on their behalf and makes a personal commitment to being available for developers to answer mid-iteration problem-domain questions. At the end of each iteration, stakeholders and the customer representative review progress and re-evaluate priorities with a view to optimizing the return on investment and ensuring alignment with customer needs and company goals.
Most agile implementations use a routine and formal daily face-to-face communication among team members. This specifically includes the customer representative and any interested stakeholders as observers. In a brief session, team members report to each other what they did yesterday, what they intend to do today, and what their roadblocks are. This standing face-to-face communication prevents problems from being hidden.
Specific tools and techniques such as continuous integration, automated or xUnit test, pair programming, test driven development, design patterns, domain-driven design, code refactoring and other techniques are often used to improve quality and enhance project agility.
Some of the principles behind the Agile Manifesto are:
* Customer satisfaction by rapid, continuous delivery of useful software
* Working software is delivered frequently (weeks rather than months)
* Working software is the principal measure of progress
* Even late changes in requirements are welcomed
* Close, daily cooperation between business people and developers
* Face-to-face conversation is the best form of communication (co-location)
* Projects are built around motivated individuals, who should be trusted
* Continuous attention to technical excellence and good design
* Self-organizing teams
* Regular adaptation to changing circumstances