Application Development for the World Wide Web

1
Application Developmentfor the World Wide Web

• Life-cycle, design models and tools
• CPSC 240 Software Engineering
• Spring 2002
• Chris Armen

2
Application DevelopmentFor The Web

• Web for Information Delivery
• Web for Application Delivery
• - Browsers are ubiquitous
• - Centralized maintenance
• - Ease of distribution

3
Problem

• Most Web development is done ad-hoc.
• Started small-scale
• Started as information-distribution
• Low-level technologies
• Immature design methodology

4
Life-cycle model for Information Delivery

• Informal analysis of material to be presented
• Divide material into chunks that become
  resources (pages)
• Implementation via markup, hyperlinks.
• Maintenance (while interest lasts)
• Author-centric

5
Emerging commercial life-cycle models

• Large-scale commercial sites now require
  something like classical life-cycle
• Requirements
• Specs
• Design
• Implementation
• Maintenance
• Many stakeholders/teams

6
Problems

• Traditional Web resource model mingles content
  and form
• Integration of database and other applications
  not modeled
• Lack of design model makes maintenance difficult

7
Commercial Tools

• Commercial IDEs exist
• E.g. Frontpage, Dreamweaver for HTML
• Various Java environments
• Very little abstraction
• Semi-automation of formatting, layout,
  templating.
• Some site-level features such as link-checking
  and version control.
• Little capacity to represent design.

8
Needed Web Development tools that

• Allow design to be expressed in terms of
  database, application logic and user interface
• Automate translation to low-level technologies
• Ease the maintenance problem

9
3 Approaches

• Relationship Management CASE (RMC)
• WebComposition Markup Language
• (WCML)
• Web Object Oriented Model (WOOM)

10
RMC Overview

• Development life-cycle in terms of a series of
  contexts.
• Each context focuses on one aspect of the
  project.
• Provides for automatic generation of final Web
  artifacts.

11
RMC E/R Context

• Focus on application domain modeling, e.g.

12
RMC Slice Design Context

• Drills down on details of an Entity.

13
RMC Navigational Design

• Predefined Navigational Modes
• One- or two- way link
• Grouping
• Indexed
• Guided Tour
• Index Guided Tour

14
RMC Navigational Context
15
RMC UI Design Context

• References Slice Context

16
RMC Population Context

• Pre-populated Applications.
• HTML generated from Contexts
• Content is pumped in.
• Dynamic Applications
• HTML generated from Contexts
• Content is provided from backend database on
  demand.

17
WebComposition Markup Language (WCML)

• Represents DBMS, content files, and services as
  in XML.
• WCML parses/compiles to HTML.
• Component
• Unit of content or service
• Any granularity unit of change

18
WCML Relationships

• WCML allows relationships to be defined among
  components
• IS-A (inheritance)
• E.g. Two login screens from Abstract login
• HAS-A (composition)
• Navigation relationships (links)

19
Web Object-Oriented Model (WOOM)

• Emphasis on software process.
• Representation of design to enable maintenance.
• Most Web Maintenance is adaptive or perfective

20
WOOM Requirements

• Requirements consist of
• Contents
• Domain-specific information
• Structuring
• Relationships and Views (how contents are
  organized)
• Access
• Indexing, queries, tours
• Layout
• Appearance

21
WOOM Design Implementation

• Resources model the domain specific content,
  including scripts.
• Elements model the strucring (views) of the
  content.
• Transformers are defined per targeted technology.
  They produce Web instances from Resources and
  Elements.

22
References

• Diaz, Isakowitz, Maiorana, Gilabert, RMC A Tool
  to Design WWW Applications, http//www.w3.org/Con
  ferences/WWW4/Papers/187
• Gellersen Gaedke, Object-Oriented Web
  Application Development, IEEE Internet
  Computing, January-February 1999.
• Coda, Ghezzi, Vigna, Garzotto, Towards a
  Software Engineering Approach to Web Site
  Development, ACM Transactions on Information
  Systems, June 2000.

23