Session 5

Object Model Development

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Review A class icon is a rectangle with three sections within it

An object is represented as a rectangle with an underlined name

Constraints are represented as strings enclosed in braces and placed near the element the constraint applies to

A comment is a graphical symbol containing information Relationships provide a pathway for communication

between objects

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Objectives

Explain use case and use case diagram Explain the three key elements of use

case diagram Elaborate the relationship amongst use

cases Define the role of use case diagram in

software development Explain the use case model with

examples

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What is Use Case?-1 Use Case diagrams help to

Focus on possible users of the system Find out the roles that users are going

to play while interacting with the system

Find out what fundamental services (use cases) the users in respective roles, expect from the system

Depict the interactions between each user or role and the services it expects from the system

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What is Use Case?-2

A Use Case is a sequence of actions a system performs that yield an observable result of value to a particular actor

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What is Use Case?-2 Uses Cases represent the specified

requirements as a series of interactions between the system and one or more actors.

The interactions help in describing the proposed functionality of the system to the users.

In the case of a complex system, use cases also provide a starting point for the analysis of the system in terms of what needs to be built.

The use cases provide a source for services provided by the system and help to determine the classes that the system must implement.

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Use Case Diagram-1

<<Actor>>Actor Name

ActorSystem Boundary Actor Class

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Use Case Diagram-2

USE CASE Name << >>

Stereotypes

Use Case

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Use Case Diagram-3

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Use Case Diagram

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Relationship amongstUse cases-1

Extends

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Relationship amongstUse cases-2

Extends

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Relationship amongstUse cases-3

Use

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Role of Use Case Diagram during development

Requirements workflow Analysis and Design, use cases are

realized in a design model Implementation in terms of design

classes Constitute the basis for identifying test

cases and test procedures Basis for planning Foundation for what is described in user

manuals Definition of ordering units

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Apply use case model-1

Defining the problem

Defining the bounds of the problem

Understanding the vocabulary associated with the problem domain

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Apply use case model-2

Bank of Aptech wants to computerize its operations. This bank will provide Retail Services to its customers. The services are defined in terms of products the bank offers. These are:

Savings Account Current Account Fixed Deposit Account of three types viz., short, medium, and long term ATM

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Apply use case model-3

Deposit money

Withdraw money

Check balance

Process transaction

Print receipt

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Apply use case model-4

Customer ATM

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Summary Use cases provide the basic ground to find out

the classes in the model

Use case diagrams exhibit the relation between the actors and system functions in the model

Most of the time, use case diagrams are the first diagram while drawing the model of a system

Use case diagrams give the broad overview of the model