Agile software development

is a group of software development methods based on iterative and incremental development, where requirements and solutions evolve through collaboration between self-organizing,cross-functional teams. It promotes adaptive planning, evolutionary development and delivery, a time-boxed iterative approach, and encourages rapid and flexible response to change. It is a conceptual framework that promotes foreseen tight iterations throughout the development cycle.

So-called lightweight agile software development methods evolved in the mid-1990s as a reaction against the heavyweight waterfall-oriented methods, which were characterized by their critics as being heavily regulated, regimented, micromanaged and overly incremental approaches to development.

In February 2001, 17 software developers met at the Snowbird, Utah resort, to discuss lightweight development methods. They published the Manifesto for Agile Software Development to define the approach now known as agile software development. Some of the manifesto's authors formed the Agile Alliance, a non-profit organization that promotes software development according to the manifesto's values and principles.

Individuals and interactions over Processes and tools

Working software over Comprehensive documentation

Customer collaboration over Contract negotiation

Responding to change over Following a plan

That is, while there is value in the items on the right, we value the items on the left more

The meanings of the manifesto items on the left within the agile software development context are:

• Individuals and interactions – in agile development, self-organization and motivation are important, as are interactions like ··co-location and ··pair programming.

• Working software – working software will be more useful and welcome than just presenting documents to clients in meetings.

• Customer collaboration – requirements cannot be fully collected at the beginning of the software development cycle, therefore continuous customer or stakeholder involvement is very important.

• Responding to change – agile development is focused on quick responses to change and continuous development.

The Agile Manifesto is based on twelve principles:

1. Customer satisfaction by rapid delivery of useful software

2. Welcome changing requirements, even late in development

3. Working software is delivered frequently (weeks rather than months)

4. Working software is the principal measure of progress

5. Sustainable development, able to maintain a constant pace

6. Close, daily cooperation between business people and developers

7. Face-to-face conversation is the best form of communication (co-location)

8. Projects are built around motivated individuals, who should be trusted

9. Continuous attention to technical excellence and good design

10.Simplicity—the art of maximizing the amount of work not done—is essential

11.Self-organizing teams

12.Regular adaptation to changing circumstances

Extreme Programming

(XP) is a software development methodology which is intended to improve software quality and responsiveness to changing customer requirements. As a type of agile software development,it advocates frequent "releases" in short development cycles, which is intended to improve productivity and introduce checkpoints at which new customer requirements can be adopted.

● Extreme Programming is a discipline of software development based on values of simplicity, communication, feedback, and courage. It works by bringing the whole team together in the presence of simple practices, with enough feedback to enable the team to see where they are and to tune the practices to their unique situation.

● In Extreme Programming, every contributor to the project is an integral part of the “Whole Team“. The team forms around a business representative called “the Customer”, who sits with the team and works with them daily.

● Extreme Programming teams use a simple form of planning and tracking to decide what should be done next and to predict when the project will be done. Focused on business value, the team produces the software in a series of small fully-integrated releases that pass all the tests the Customer has defined.

● Extreme Programmers work together in pairs and as a group, with simple design and obsessively tested code, improving the design continually to keep it always just right for the current needs.

● The Extreme Programming team keeps the system integrated and running all the time. The programmers write all production code in pairs, and all work together all the time. They code in a consistent style so that everyone can understand and improve all the code as needed.

● The Extreme Programming team shares a common and simple picture of what the system looks like. Everyone works at a pace that can be sustained indefinitely.

● XP teams build software to a simple design. They start simple, and through programmer testing and design improvement, they keep it that way. An XP team keeps the design exactly suited for the current functionality of the system. There is no wasted motion, and the software is always ready for what’s next.

Rules of XP

● Planning● Managing● Designing● Coding● Testing

Adaptive Software Development

(ASD) is a software development process that grew out of rapid application development work by Jim Highsmith and Sam Bayer. It embodies the principle that continuous adaptation of the process to the work at hand is the normal state of affairs.

Adaptive Software Development replaces the traditional waterfall cycle with a repeating series of speculate, collaborate, and learn cycles. This dynamic cycle provides for continuous learning and adaptation to the emergent state of the project. The characteristics of an ASD life cycle are that it is mission focused, feature based, iterative, timeboxed, risk driven, and change tolerant.

The word speculate refers to the paradox of planning – it is more likely to assume that all stakeholders are comparably wrong for certain aspects of the project’s mission, while trying to define it.

Collaboration refers to the efforts for balancing the work based on predictable parts of the environment (planning and guiding them) and adapting to the uncertain surrounding mix of changes caused by various factors – technology, requirements, stakeholders, software vendors, etc.

The learning cycles, challenging all stakeholders, are based on the short iterations with design, build and testing. During these iterations the knowledge is gathered by making small mistakes based on false assumptions and correcting those mistakes, thus leading to greater experience and eventually mastery in the problem domain.