Requirements Analysis 21. 1 Moving to Design - 2005b521.ppt © Copyright De Montfort University 2000 All Rights Reserved INFO2005 Requirements Analysis

Requirements Analysis 21. 1 Moving to Design - 2005b521.ppt

© Copyright De Montfort University 2000All Rights Reserved

INFO2005Requirements Analysis

Moving to Design

Department of Information Systems



Learning Objectives

Examine the issues that have to be addressed during design

Distinguish between System and Object Design

Consider the impact of implementation technology

UP, Design and Implementation



Analysis vs Design

Why separate analysis and design Project Management, Staff Skills and Experience, Client Decisions Choice of Development Environment.



What makes a good analysis To provide a sound foundation for

design, analysis should meet the following four criteria:



What makes a good design



What makes a good design



Measurable Objectives

Information systems are built to satisfy an organisational need such as

Measurable objectives might include

However not all objectives are quantifiable



Logical vs Physical Design

One way of separating design by splitting it into – Logical design – Physical design




Physical design is affected by




Logical design is concerned – how objects interact determining




One logical design leads to various physical designs (and implementations).

Distinction made much less these days

System architecture enables different styles of implementation



System and Object Design

System Design is concerned with

Object Design is



System Design

Sub-systems and major components are identified.

Any inherent concurrency is identified.

Sub-systems are allocated to processors.



System Design

A data management strategy is selected.

A strategy and standards for human-computer interaction are chosen.

Code development standards are specified.



System Design

The control aspects of the application are planned.

Test plans are produced. Priorities are set for design trade-offs. Implementation requirements are

identified (for example, data conversion).

Architectural patterns may be used.



System Design

Campaign Database

Campaign Domain

Advert Sub-system

Advert HCI Sub-system

Campaign Costs Sub-system

Campaign Costs HCI Sub-system

A single domain layer supports two application sub-systems.

Application layer

Presentation layer

A typical software architecture

Bennett, McRobb, Farmer, 1999



User Interface Package

Business Objects Package

JDBC

Java SQL

Java AWT Application Windows

Database Package Business Objects

Control Objects

Object to Relational

UML packages representing layers in the three-tier architecture

Bennett, McRobb, Farmer, 1999



Detailed or Object Design

This involves making decisions regarding



Object Design

BankAccount

-nextAccountNumber:Integer -accountNumber:Integer -accountName:String {not null} -balance:Money = 0 -overdraftLimit:Money

+open(accountName:String):Boolean +close():Boolean +credit(amount:Money):Boolean +debit(amount:Money):Boolean +viewBalance():Money #getBalance():Money -setBalance(newBalance:Money) #getAccountName():String #setAccountName(newName:String)

Bennett,McRobb,Farmer, 1999



RUP Phases

Inception– business case– plan

Elaboration– use cases– baseline architecture

Construction– product is built

Transition– beta release/testing/training

Rational Unified Process



The Rational Unified Process

Rational Unified Process



The Analysis & Design Workflow

Rational Unified Process 2000



Design Activities

Centred around the software architecture

Production of the Design Model



Implementation & UP

The purpose of implementation is: – to define the organization of the code, in terms of

implementation subsystems organized in layers, – to implement classes and objects in terms of

components (source files, binaries, executables, and others),

– to test the developed components as units, and – to integrate the results produced by individual

implementers (or teams), into an executable system.



Summary

Examine the issues that have to be addressed during design

Distinguish between System and Object Design

Consider the impact of implementation technology

UP, Design and Implementation



References Bennett, S. et. al. “Object-Oriented

Systems Analysis & Design using UML” McGraw-Hill 2002

Jacobson, I., Booch, G. & Rumbaugh, J. (1999) “The Unified Software Development Process” Addison-Wesley

Rational Unified Process Best Practices for Software Development Teams White Paper, 1998 www.rational.com

Rational Unified Process 2000

Documents

Requirements Analysis 21. 1 Moving to Design - 2005b521.ppt © Copyright De Montfort University 2000 All Rights Reserved INFO2005 Requirements Analysis