Based on the book by David William Brown

1Copyright 8 2002 Flying Kiwi Productions Inc. [email protected]

An Introduction toAn Introduction to

Object-Oriented Object-Oriented AnalysisAnalysis

Objects and UML in plain English.Objects and UML in plain English.

Chapter 6: The Object-Oriented Chapter 6: The Object-Oriented Development Life CycleDevelopment Life Cycle

Based on the book by

David William BrownJohn Wiley & Sons, ISBN 0471371378


Chapter 6: The Object-Oriented Chapter 6: The Object-Oriented Development Life CycleDevelopment Life Cycle

(OODLC)(OODLC)6.1. The Life Cycle

6.2. The Object-Oriented Analysis Phase

6.3. The Object-Oriented Design Phase

6.4. The Construction Phase

6.5. The Object-Oriented Testing Phase

6.6. The Maintenance Phase


Chapter 6: The Object-Oriented Development Life Cycle (OODLC)

6.1. The Life Cycle

The OODLC is an update of the older SDLC In this chapter we will overview the OODLC Beginning in Chapter 7 we will look at

detailed step-by-step methods for doing the Analysis Phase.

The aim in this chapter is to see how all the pieces fit together.

We examine the Analysis Phase in detail since it is the focus of this course.



6.1. The Life Cycle

Phase

Analysis

Design

Construction

Testing

Maintenance

Activity

OOA

OOD

OOP

O-O Testing

All of the above

ModelsProduced

RequirementsModel

Design versions ofthe OO models

Actual system

Working system

All of the above

Components

Project scope

Feasibility study

Context diagram

Class diagram:

Entity classes

Interface classes

Control classes

Behavior diagrams:

Statechart diagrams

Collaborations and CRC cards

Sequence diagrams

Activity diagrams



6.1. The Life Cycle

6.2. The Object-Oriented Analysis Phase6.2. The Object-Oriented Analysis Phase








In Analysis we model the users’ requirements

For what the eventual system must DODO..Output of this process is a conceptual conceptual

modelmodelThe conceptual model consists of 3

deliverables:deliverables: Requirements Model Object Model Statechart model



6.2. The Object-Oriented Analysis Phase Requirements Model

Now let’s look at these in detail. . .Now let’s look at these in detail. . .

The Requirements model has 5 components:

Project ScopeContext Diagram Use Case Model Interface Descriptions Feasibility study




The Project ScopeProject Scope is a statement of what what our project is to produce.our project is to produce. States in general terms what the system will do for

the users. What functions will be part of it. Which user it will service.

May be a paragraph or two, Or many pages, depending on the size of the project.

There is much variation in size and format among companies and methodologies.




It is also important that the Scope say what the system will will

notnot do,do,Otherwise the users will try to

“push the scope”“push the scope”Which causes “Scope Creep.”“Scope Creep.”

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Copyright 8 2002 Flying Kiwi Productions Inc. [email protected]



The Context Diagram:Context Diagram:Shows our system as a large box,Surrounded by smaller boxes,Representing External Entities:External Entities:

ie., People, organizations, systems and other things outside our system outside our system that either provide data to it or draw data from it.

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Context DiagramContext Diagram

Radio CHQT Advertisers Database

SystemAdvertisers

RegulatoryAuthorities

RevenueCanada

Shareholders

Listeners BetterBusinessBureau

Requests

Billing

Statistics &Reports

ProgramInfo

CreditRatings

QuarterlyReports

FinancialReports

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6.2. The Object-Oriented Analysis Phase Use Case Model

Proposed by Jacobson et al. 92.

A Use CaseUse Case is a script,A step-by-step description of how a

user might make use of the systemTo do a task. It is a “case of the usage of the system.”“case of the usage of the system.”

See Ch 7 for details.

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Interface DescriptionsInterface Descriptions

GUI: interface to users Interface to other I.S. Systems:Real-World systems that we

control communications interfaces: System (hardware/software network

protocols) interfaces Person-machine interfaces

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Feasibility AnalysisFeasibility Analysis

Can we do this project?ShouldShould we?Can we make it work? (e.g. need

technical resources) Is the cost worth it? (is it worth

spending the money)Do we have enough time to finish

it?

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In other words: Operational feasibility Technical feasibility Schedule feasibility Economic feasibility

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Operational feasibility Will the proposed system do the job being

asked for? response time, throughput, …

Will it work in this company? political acceptability, management of

changes It is worth the effort to find a solution?

Will it has positive impact on the working lives of the users?

Will it increase company revenue and/or cut costs?

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Technical feasibility Hardware and software

Capacity (PDAs for e-map)Availability (Can we get what we don’t

have?) Technical knowledge

Training Consultants

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Schedule feasibility Can it be done in the time allowed?

Which deadlines are mandatory and which are desired?

Late panalties

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Economic feasibility Cost-benefit analysis Costs:

Development cost (wages, computers hardware/software resources, training, office support costs, …)

Benefits:Tangible benefits (save time for users,

improve response times, reduces expenses,..)

Intangible benefits (customer goodwill, better data, better decision-making, …)

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6.1. The Life Cycle


6.3. The Object-Oriented Design Phase 6.3. The Object-Oriented Design Phase




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Modify Analysis model to reflect design decisions, Mostly by adding information to the existing model.

Conceptual model Logical Model Physical Model Add some new classes that do not directly model

things in the real world. Result is a planplan (a physical model) of howhow the

system will do what the Requirements Analysis asks for

6.3. The Object-Oriented Design Phase6.3. The Object-Oriented Design Phase

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AnalysisAnalysis is is whatwhat the system the system

must do,must do,

DesignDesign is is howhow the system the system

will do it.will do it.


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6.1. The Life Cycle



6.4. The Construction Phase 6.4. The Construction Phase 6.5. The Object-Oriented Testing Phase


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Coding and testing Should be done with an O-O language or database.

Deployment and user training.


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6.1. The Life Cycle




6.5. The Object-Oriented Testing Phase6.5. The Object-Oriented Testing Phase


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Complete the unit testing of individual classes and programs

Then system testing. Testing must be thorough and complete, And automatedautomated. For Testing and Quality Assurance see chap

15.

6.5 The Object-Oriented Testing Phase

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6.1. The Life Cycle





6.6. The Maintenance Phase 6.6. The Maintenance Phase

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Maintenance starts when a system is built and signed off.

Maintenance activities: Bug fixes Enhancements Viruses (bugs caused by viruses) End-user computing (report generator,

spreadsheets …) Backups and restores

3 levels + offsite. Disaster preparedness and recovery

The World Trade Center bombing.Murphy’s Law


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Requirement model Project scope Feasibility analysis Context diagram User case model Interface descriptions

Object model: Class diagrams Class definitions Attribute lists and definitions Notes and business rules

Statechart diagram

Deliverables

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End of Chapter 6.

Documents

Based on the book by David William Brown