An Introduction to Web Engineering

An Introduction to Web Engineering Week 1 Definition of Software Engineering • Software f Engineering g g is defined f as the application of science and mathematics by p off computer p equipment q p which the capabilities are made useful to man via computer programs, p g ,p procedures,, and associated documentation. Definition of Web Engineering • Web Engineering g g is the application pp off systematic and quantifiable approaches ((concepts, p , methods,, techniques, q , tools)) to cost‐ effective requirements analysis, design, p , testing, g, operation, p , and implementation, maintenance of high‐quality Web applications. Chapter 1: Web-Based Web Based Systems • In the early days of the Web, we built systems using informality, urgency, intuition, and art – Informality leads to an easy work environment—one environment one in which you can do your own thing. – Urgency leads to action and rapid decision making. – Intuition is an intangible quality that enables you to “feel” feel your way through complex situations. – Art leads to aesthetic form and function—to something that pleases those who encounter it. p • Problem is—this approach can and often does lead to problems The Web • An indispensable technology – In virtually every aspect of modern living • A transformative technology – Changes the way we do things – Changes the way we acquire and disseminate information • An evolving technology • Bottom line—high impact on everyone in the modern world WebApps • The term Web application (WebApp) encompasses: – everything from a simple Web page that might help a consumer compute an automobile lease payment to a comprehensive website that provides complete travel services for business people and vacationers. – Included within this category g y are complete p websites,, specialized functionality within websites, and information‐ processing applications that reside on the Internet or on an Intranet or Extranet Extranet. WebApp Attributes • Network intensiveness • Content sensitive • Concurrency • Continuous evolution • Unpredictable load • Immediacy • Performance • Security • Availability • Aesthetics • Data driven WebApp Types • Informational • Transaction‐oriented • Download • Service‐oriented • Customizable C t i bl • Portals P t l • Interaction • Database access • User input • Data warehousing CO OMPLEXITY UBIQUITOUS •Location-Aware Service •Multi-Platform Delivery •Customized Service COLLABORATIVE •Chat room •E-Learning Platform •P2P-Service SEMANTIC WEB •Knowledge Management •Recommender System •Syndication SOCIAL WEB •Virtual Shared Workspace •Collaborative Filtering •Weblogs WORKFLOW-BASED •E-Government •B2B Solution TRANSACTIONAL•Patient Workflow •Online Banking •Online Shopping •Booking Booking System PORTAL-ORIENTED •Community-Portal •Online Shopping Mall •Business Portal INTERACTIVE •Virtual Exhibition •News Site •Travel Planning DOCUMENT-CENTRIC •Static Homepage •Web Radio •Company Web Site DEVELOPMENT HISTORY Categories of Web Applications Why Web Engineering? • As WebApps become larger and more complex, – Informality remains, but some degree of requirements gathering and planning are necessary – Urgency remains, but it must be tempered by a recognition that decisions may have broad consequences – Intuition remains, remains but it must be augmented by proven management and technical patterns – Art remains, but it must be complemented with solid design • Bottom line: – we must adapt the old‐school approach to the realities of a Web 2.0 world Chapter 2: Web Engineering • We define it this way: – an agile, yet disciplined framework for building industry‐ quality WebApps. • We must understand the meaning of: – Agile – Disciplined framework – Industry quality Why Agility? • Business strategies and rules change rapidly • Management demands near‐instantaneous responsiveness i ((even when h such h demands d d are completely unreasonable • Stakeholders often don’t understand the consequences of the Web and keep changing their mind even as they demand rapid delivery agilee approach app oac helps e ps cope with t this t s fluidity u d ty and a d • An ag uncertainty. What is an Agile Process? • Agile Web engineering combines a philosophy and a set of development guidelines. The philosophy encourages: – – – – – – customer satisfaction early incremental delivery of the WebApp small, highly motivated project teams informal methods minimal work products overall development simplicity. What is an Agile Process? (cont’d) (cont d) • An agile process process stre stressses deliver deliveryy ov over er analys analysis and design (although these activities are not discouraged), and active and continuous communication between developers and customers. Underlying Agility Principles - I 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 continuous change for the customer's competitive advantage. • Deliver working software increments frequently, from as often as every few days to every few months, months with a preference to the shorter timescales. • Business people and developers must work together daily throughout the project. • Build projects around motivated people. 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 face to face conversation. conversation • Underlying Agility Principles - II • Working software is the primary measure of progress. • Agile processes promote sustainable development. The sponsors, developers, p , and users should be able to maintain a constant pace p indefinitely. • Continuous attention to technical excellence and good design enhances agility. g y • Simplicity—the art of maximizing the amount of work not done—is essential. • The best architectures, architectures requirements, requirements and designs emerge from self self‐ organizing teams. • At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behavior accordingly. accordingly What is a WebE Framework? • A framework is a set of activities that will always be performed for every Web engineering project – though the nature of the activities might g varyy to suit the project. p j • Each framework activity is composed of a set of actions • Actions i encompass – – – – work tasks work products q alit assurance quality ass rance points, points and project milestones • A framework also has a set of “umbrella umbrella activities” activities A Generic Framework The WebE Framework: Activities Communication. Involves heavy interaction and collaboration with the customer (and other stakeholders) and encompasses requirements gathering and other related activities. • Planning. Establishes an incremental plan for the WebE work. • Modeling. Encompasses the creation of models that assist the developer and d the h customer to b better understand d d WebApp b requirements and d the h design • Construction. Combines both the generation of HTML, XML, Java, and similar code with testing that is required to uncover errors in the code. code • Deployment. Delivers a WebApp increment to the customer who evaluates it and provides feedback based on the evaluation. • Adapting the Framework • Adapt to the problem, to the project, to the team, and to the organizational culture • And continue to adapt throughout the project as circumstances change! • Adaptation leads to: • • • • • • • • • Overall flow of activities, actions, and tasks and the interdependencies among them Degree to which work tasks are defined within each framework activity Degree to which work products are identified and required Manner in which quality assurance activities are applied Manner in which project tracking and control activities are applied Overall degree of detail and rigor with which the process is described Degree to which customers and other stakeholders are involved with the project Level of autonomy given to the software project team Degree to which team organization and roles are prescribed The Influence of Software Engineering • Quality: foster a continuous process improvement culture • Process: the gglue that holds the technology gy layers y together g • Methods: provide the technical how‐to’s • Tools: support for the process and the methods WebE Methods • Communication methods • Requirements analysis methods • Design methods • Construction methods • Testing methods What about Tools and Technology? … tools and technology gy are veryy important, p , but they’ll work well only if they’re used within the context of an agile framework for Web engineering and in conjunction with proven methods for understanding the problem, designing a solution, and testing it thoroughly. WebE Best Practices • Take the time to understand business needs and product objectives, even if the details of the WebApp are vague. • Describe how users will interact with the WebApp using a scenario‐based approach. • Always develop a project plan, even if it’s very brief. • Spend p some time modelingg what it is that yyou’re ggoingg to build. • Review the models for consistency and quality. • Use tools and technology that enable you to construct the system with as many reusable components as possible. possible • Don’t reinvent when you can reuse. • Don’t rely on early users to debug the WebApp—design and use comprehensive h tests b before f releasing l the h system.