agile software development 2

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StaffordshireUNIVERSITYSchool of Computing

Slide: 1Prototyping

Agile Software Development 2

Agile Methods and

Software Architectures

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Slide: 2Prototyping

Agenda

Agile Manifesto

Agile Methods

Agile and RAD

Multi-Tier Architectures

Iterative Design

Some Trends

Tutorial Tasks

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Slide: 3Prototyping

Agile Manifesto

Formation of the Agile AllianceOn February 11–13, 2001, at The Lodge at Snowbird ski resort in the Wasatch mountains of Utah, 17 people met to talk, ski, relax and try to find common ground. What emerged was the Agile Software Development Alliance.

Manifesto for Agile Software Development:We are uncovering better ways of developingsoftware by doing it and helping others do it.

This produced Agile Values and Agile Principles

See for example:www.agilemanifesto.orgwww.ambysoft.com/essays/agileManifesto.html

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Slide: 4Prototyping

Agile Manifesto

Agile Values

We are uncovering better ways of developingsoftware by doing it and helping others do it.

Through this work we have come to value:

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.

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Slide: 5Prototyping

Agile Manifesto

Agile Principles (1-3)

Our highest priority is to satisfy the customer through early and continuous delivery of valuable software.

Welcome changing requirements, even late in development. Agile processes harness change for the customer's competitive advantage.

Deliver working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter timescale.

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Slide: 6Prototyping

Agile Manifesto


Business people and developers must work together daily throughout the project.

Build projects around motivated individuals. Give them the environment and support they need, and trust them to get the job done.

The most efficient and effective method of conveying information to and within a development team is face-to-face conversation.

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Slide: 7Prototyping

Agile Manifesto


Working software is the primary measure of progress.

Agile processes promote sustainable development. The sponsors, developers, and users should be able to maintain a constant pace indefinitely.

Continuous attention to technical excellence and good design enhances agility.

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Slide: 8Prototyping

Agile Manifesto


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

The best architectures, requirements, and designs emerge from self-organizing teams.

At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behaviour accordingly.

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Slide: 9Prototyping

Agile Methods

Agile methods reduce software lifecycle time (thus speeding up development) by firstly developing a prototype version, then integrating functionality on an iterative basis responding to customer requirements and testing throughout the development cycle

Agile methods originate from the instability of the technical environment and the fact that the client is often unable to define every single requirement at the start of the project.

See: http://en.kioskea.net/contents/genie-logiciel/methodes-agiles.php3

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Slide: 10Prototyping

Agile Methods

The term "agile" is a reference to the ability to adapt to contextual changes and changes to specifications which occur during the development process.

With the help of agile methods, the customer is in total control of his project and achieves rapid software implementation.

Thus, this allows for user involvement from the beginning of the project.

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Agile Methods

RAD - Rapid Application Development

DSDM - Dynamic Software Development Method

UP - Unified Process

RUP - Rational Unified Process

XP - Extreme Programming

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Agile Methods

RAD (Rapid Application Development) was defined by James Martin in the early 1980s, and consists of a short development cycle based on 3 phases (Requirements, Design and Construction) with an ideal delivery time of between 90 and 120 days maximum.

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Agile Methods

The DSDM (Dynamic Software Development Method) was developed to fill in some of the gaps in the RAD method by providing a framework which takes into account the entire development cycle.

The main features of the DSDM method are as follows:

User involvement

Iterative and incremental development

Increased delivery frequency

Integrated tests at each phase

The acceptance of delivered products depends directly on fulfilling requirements.

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Agile Methods

The UP (Unified Process) method is an iterative and incremental development process which means that the project is cut into very short phases, where a new incremental version is delivered at the end of each phase.

This approach is based on UML modelling for the description of software architecture (functional, applicational and physical), and user case development which outlines user requirements and demands.

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Agile Methods

The RUP (Rational Unified Process) is an iterative development method promoted by the Rational Software company, which was bought by IBM.

The RUP method mainly specifies team make-up and time scales as well as a number of document models.

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Agile Methods

The XP method (eXtreme Programming) defines a set of best practices for application development in optimal conditions by placing the customer at the centre of the development process, maintaining a close relationship with the customer.

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Agile and RAD

Agile and RAD – beware

When many people look at agile development, they see reminders of the "quick and dirty" RAD efforts of the previous decade.

But, while agile development is similar to RAD in terms of speed and flexibility, there's a big difference when it comes to technical cleanliness.

Agile approaches emphasize quality of design, because design quality is essential to maintaining agility.

http://hristov.com/andrey/fht-stuttgart/The_Agile_Manifesto_SDMagazine.pdf

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Some Architecture Development Milestones

Mainframe Computing

PC Workstation and File Server

Client/Server Models

See http://channukambalyal.tripod.com/NTierArchitecture.pdf

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http://en.wikipedia.org/wiki/Multitier_architecture

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http://www.webopedia.com/quick_ref/app.arch.asp

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Iterative Design

Initial Iterative Design

Persevere – don’t skip this initial stage (want to “get on with” the project)

Wireframe

White Screen Prototype

then the two paths (Tech and Design) can diverge

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Some Trends

Local developments not National developments?

C-NOMIS

The project began in June 2004. But it was not until 2007 that senior officials discovered that C-Nomis was running two years late and that costs had more than doubled from £234m to a projected £690m over the lifetime of the scheme.

NPfIT - Health Service IT

Problems with technology, contracts, timescales, organisational change, and user acceptance have continually dogged the NHS national programme for IT (NPfIT)

Connexions Web sites

Home Office and NHS/NTA Data Capture

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Tutorial Tasks

In small groups discuss the requirements for a Membership Organisation Web based Database

Level 1: Public Access (see all organisations)

Level 2: Member Access (additional information & edit information)

Level 3: Staff Access (membership renewals, key contacts)

Level 4: Client Relationship Management Core

Adopt the roles of

Client (Persona & Goals)

Developer (produce wireframe)

Develop an html Wireframe (using Notepad or other)

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Agenda

Agile Manifesto

Agile Methods

Agile and RAD


Iterative Design

Some Trends

Tutorial Tasks

agile software development 2

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