176 CONCEPTUAL DESIGN: OBJECT TECHNOLOGY CONCEPTS and UML CLASS DIAGRAMS.

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CONCEPTUAL DESIGN:

OBJECT TECHNOLOGY

CONCEPTS and

UML CLASS DIAGRAMS

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1. Identify the information system’s purpose

2. Identify the information system’s actors and features

3. Identify Use Cases and create a Use Case Diagram

4. Identify Objects and their Classes and create a Class Diagram

5. Create Interaction/Scenario Diagrams

6. Create Detail Logic for Operations

7. Repeat activities 1-6 as required to refine the “blueprints”

A Simplified Object-OrientedSystems Analysis & Conceptual Design Methodology

Activities

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Object-Oriented Technology Concepts

• Object

• Class

• Attributes

• Operations

• Relationships

• Messages

• Persistence

• State

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Defining ObjectsAn OBJECT is an abstraction of a person, place,thing, or concept within the problem domain thatthe information system must be aware of.

...Objects are “instantiated” (created)

...the term “instance” is interchangeable with “object”

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Defining ClassA CLASS is a template (specification, blueprint)for a collection of objects that share a commonset of attributes and operations.

HealthClubMemberClass

Objects

attributesoperations

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• Objects have three responsibilities:

What they know about themselves – (e.g., Attributes)

What they do – (e.g., Operations)

What they know about other objects – (e.g., Relationships)

Objects

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•Attributes (aka: properties, characteristics)

An ATTRIBUTE is data that further describes an object instance.

HealthClubMember

Class

Objects

• attributes• firstName• lastName• etc...

• operations

firstName lastNameMary SmithSusan JonesJeff Normanetc...

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An example ofa Class showingAttribute Namesand their Values

studentName address shoeSize eyeColor weight dateOfBirthSusan McIntyre

Greg Fisher

Minder Chen

Sally Athey

Laura Applegate

Margie Heltne

Bill Martz

Anna Easton

123 Franklin St.San Diego CA765 Park Ave.San Diego CA222 Dallas St.La Mesa CA862 Grand Ave.Pacific Beach CA914 GarnettLa Jolla CA479 55th St.El Cajon CA876 BalboaMission Beach CA309 Del Mar Hts.Del Mar CA

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10

9.5

6

5

5.5

10.5

6

Blue

Brown

Brown

Brown

Blue

Brown

Blue

Brown

175

170

140

125

110

105

190

120

4-12-74

12-2-73

10-5-76

6-28-75

3-15-74

5-22-75

1-26-70

8-14-74

StudentInformationstudentNameaddressshoeSizeeyeColorweightdateOfBirthetc...

operations

Class “template”

8 Object ExamplesWith

Attribute Values

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Candidate Attributes Necessary AttributesstudentSocialSecurityNumberstudentFirstNamestudentMiddleInitialstudentLastNamestudentAddressstudentCitystudentStatestudentZipcodestudentTelephoneyearGradFromHighSchoolhighSchoolGradePointAvgsATScorehobbiessportsreligiousPreferencemedicalConditionheightweightshoeSizehairColoreyeColorgenderetc...

StudentInformationattributes

studentSocialSecurityNumberstudentFirstNamestudentMiddleInitialstudentLastNamestudentAddressstudentCitystudentStatestudentZipcodestudentTelephoneyearGradFromHighSchoolhighSchoolGradePointAvgsATScore

religiousPreferencemedicalCondition

genderetc...

ANALYSIS

operations

What are the necessary attributes?

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Single-Valued Attributes Example

studentName studentIDNumber eyeColor height weight dateOfBirth

Susan McIntyre

Bill Martz

Blue

Brown

155

118

4-12-74

12-2-73

559-46-0912

371-38-7640

5ft 9in

5ft 6in

(each object has one and only one value for each attribute at any moment in time)

Mutually Exclusive Attribute Values Example

employeeName employeeNumber hourlyRate weeklySalary

Susan McIntyre

Bill Martz

$9.75559-46-0912

371-38-7640 $475.00

mutually exclusive attributes with values

(the presence of an object’s attribute value necessitates the absence of a value for another attribute value for the same object)

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studentName studentIDNumber collegeAttended collegeGradePointAvg

Multi-Valued Attributes ExamplestudentName studentIDNumber collegeAttended collegeGradePointAvgSusan McIntyre

Bill Martz

Maria Carey

Grossmont C.C.Point Loma

NY Univ.

Golden GateGeorgia StateU of San Diego

559-46-0912

371-38-7640

270-73-9815

2.92.7

3.2

2.22.93.1

multi-valued attributes with values

Susan McIntyreSusan McIntyre

Bill Martz

Maria CareyMaria CareyMaria Carey

Grossmont C.C.Point Loma

NY Univ.

Golden GateGeorgia StateU of San Diego

559-46-0912559-46-0912

371-38-7640

270-73-9815270-73-9815270-73-9815

2.92.7

3.2

2.22.93.1

Notice the redundancy of data values for these two attributes

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StudentInformation

operations

studentNamestudentIDNumbercollegeAttendedcollegeGradePointAvg

StudentInformation

operations

studentNamestudentIDNumber

CollegeAttended

operations

collegeAttendedcollegeGradePointAvg

1

0,m

(original model) (revised model)

Susan McIntyre

Bill Martz

Maria Carey

559-46-0912

371-38-7640

270-73-9815

Grossmont C.C.Point Loma

NY Univ.

Golden GateGeorgia StateU of San Diego

2.92.7

3.2

2.22.93.1

collegeAttended gradePointAvg

studentName studentIDNumber

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•Operations (aka: methods, services, behavior)

An OPERATION is a procedure that an object can perform.

HealthClubMember

Class

Objects

• attributes• firstName• lastName• etc...

• operations• joinClub• payFees• monitorWorkout• etc...

“I do it myself”

An object’s “motto”:

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• RelationshipsA RELATIONSHIP is what a class or an object

knows about another class or object.

Generalization[-Specialization] (Superclass/Subclass)

• Inheritance• Ex: Person - FacultyPerson, StudentPerson, Staff...

• Ex: ModesOfTravel - Airplane, Train, Auto, Cycle, Boat...

[Object] Associations• FacultyInformation - CourseInformation• StudentInformation - CourseInformation

[Object] Aggregations & Composition (Whole-Part)

• Assembly - Parts• Group - Members• Container - Contents

T h

r e

e

T y

p e

s

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• Relationships

1) show relationships 2) enforce integrity 3) help produce results

• Removal of a course should also remove students that are in the course but not student information.

• Removal of a student should also remove students that are in courses but not course information.

• Removal of a student in a course should not affect either course or student information.

1

0,m

UniversityCourse

StudentInCourse

StudentInformation

1

0,m

Exist to:

In this example:

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• MessagesA MESSAGE is a signal from one object to

another that requests the receiving object to carry out one of its operations.

Three parts to a Message:

1. The name of the receiver object

2. The operation to carry out

3. Any parameters the operation may

require to fulfill its duties

Message: getFrozenYogurt

operation: getFrozenYogurt($$)

“The operation

is the message.”

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VCR Example

VCR Class Definition

VCR Object

Universal Remote Control

T.V. Object

PlayPlay Message

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• PersistencePERSISTENCE is the equivalent of more

permanent, long-term data storage.

• StateSTATE represents the condition of an object at a specific moment in time.

Time Account Balance6:00pm $2,5006:05pm $2,200 (something changed its state)

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Getting Started!

Getting Started!

Getting Started!

Getting Started!

Getting Started!

Getting Started!

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GETTING STARTED with the CLASS DIAGRAM

OBJECTS!

(CLASSES)

Features?

Data?

User Behavior?

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UML Class Diagram Notation

Member

memberNumberfirstNamelastNametelephoneaddresscityetc...

checkOutVideocheckInVideobuyItemetc...

attributes

operations

{{

Expanded view of a

Class into its three

sections:

Top: Class Name

Middle: attributes

Bottom: operations

Class

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Playing Card Illustration of Class Symbol

Deckof 52

PlayingCards

. ..

..

card #1card #2

card #3card #4

card #52

Class

Class

Object #1Object #2

Object #3Object #n

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STRATEGIES for FINDING OBJECTS (Classes)

Wirfs-Brock Noun Phrase

Conglomeration of others:

• Look for tangible things

• Consider roles played

• Identify incidents/interactions which are often

transaction-like

• Find any specifications (table-like)

• Other…

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Wirfs-Brock Noun Phrase (also Wilkerson, Wiener)

• Circle or underline nouns and noun phrases

that occur in the requirements document(s);

these become candidate classes (objects)

• Put candidate classes on a separate list

• Challenge each one; look for synonyms

Examples:The system will keep track of membership informationThe system will manage inventoryThe system will facilitate the selling of bicycles

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INFORMATION SYSTEMS OBJECTIVES

GENERAL OBJECTIVES:

A. Provide Just-in-Time (JIT) trainingB. The systems we implement must be friendly and easy to learn and useC. The systems we implement must give considerations to security issues

SPECIFIC OBJECTIVES:

1.1.1 Provide an automated system to assist with customer sales/rental check-outs

2.1.1 Provide and maintain an automated membership database a. provide current (up to date) membership information on demand b. capability to add, change, and delete (remove) membership info.

2.1.2 Provide membership information reports such as (not limited to): a. least used memberships b. most used memberships c. delinquent memberships (both money owing and outstanding rentals)

4.1.1 Provide and maintain an inventory database for both sales and rental items a. provide current (up to date) inventory information on demand b. capability to add, change, and delete (remove) inventory information (sales and rental)

4.1.2 Provide inventory information reports such as (not limited to): a. least popular rentals b. most popular rentals c. delinquent tape rentals outstanding d. products “on order” (purchasing report) for sale and for rent items

5.1.1 Provide Sales Reports such as (not limited to): a. sales for a time period (day, days, week, weeks, month, etc.) by product code b. rentals for a time period (same as above)

F i n d i n g

O b j e c t s

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Security Issue

Automated System

Customer Sales/Rental Check-out

Membership Database

Membership Information

Membership Information Report

Inventory Database

Sales And Rental Item Inventory Information

Inventory Information Report

Sales Report

Candidate List of Classes

WIRFS-BROCK NOUN PHRASE STRATEGY

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Look for tangible things• people, places, things

Consider roles played• student, faculty, clerk, manager, salesperson, race car driver,

etc...

Identify incidents/interactions which are often transaction-like• sales, purchases, reservations, etc...

Find any specifications (table-like)• state tables, tax rate tables, zipcode table, shipping region

table, etc...

OtherStrategies

ToFind

Objects

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CHALLENGE CLASSES/OBJECTS BASED ON:

Needed remembrance (persistence)

No Attributes

No Operations

Only one Object

Avoid derived (computed) results

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(CRC = Class-Responsibility-Collaboration)

4x6 Card

Class Name

Responsibilities(attributes andoperations)

Collaborations(relationships)

Order

orderNumberorderDatecheck if items in stockdetermine pricecheck for valid paymentdispatch to delivery addressetc...

Order LineOrder LineCustomer

etc...

BECK & CUNNINGHAM’s CRC STRATEGY(low-fidelity/tech way of documenting classes)

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Candidate List of Classes - Pass One

• Members• Customers• Movies• Reports• Concessions• Sales• Games• Inventory• VCR Rentals• Movie Rental• Employees• Automated System• Hardware• Software• Back-up System

• Bonus Plan• P.O.S. Terminal• Clothing• Transaction• Marketing• Popcorn• Prices• Physical Environment• Scheduling• Location• Accounting• Advertising• Overhead• Database• Payroll

Video Store Information System

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List of Classes – Final Pass

• RentalTransaction

• Member

• Employee

• StoreLocation

• Supplier

• Purchase Order

• Purchase Order Line Item

• SaleRentalLineItem

Note: * denotes an Abstract Class (no Objects)

• Inventory *

• Video

• Game

• ConcessionItem

• VCR

• Transaction *

• SaleTransaction

• SaleItem*

• RentalItem*

Video Store Information System

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Video StoreClasses

showing Attributes - Part 1 of 3

Member memberNumbermemberNamememberAddressmemberCitymemberStatememberZipCodememberPhonecreditCardNumbercreditCardExpireDatedepositAmount

Video barCodeNumberdescriptionqtyOnOrderpricecosttaxCodetimesRenteddueDatememberNumberquantitySoldqtyOnHand

Class Attributes

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Game (same as Video)

ConcessionItem barCodeNumberdescriptionqtyOnOrderpricecosttaxCodequantitySoldqtyOnHand

VCR barCodeNumberdescriptionqtyOnOrderpricecosttaxCodetimesRenteddueDatememberNumber

SalesTransaction transactionNumberemployeeNumbertransactionDatetransactionTimebarCodeNumberpricesalesTax

quantitySold

Class Attributes

Video StoreClasses

showing Attributes - Part 2 of 3

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RentalTransaction transactionNumberemployeeNumbertransactionDatetransactionTimebarCodeNumberpricesalesTax

memberNumber

Employee employeeNumberemployeeNameemployeePhonepositionCode

StoreLocation storeNumberaddresscitystatezipcodetelephone

Vendor vendorNumbervendorNamevendorAddressvendorCityvendorStatevendorZipCodevendorPhonevendorFaxNumber

PurchaseOrder purchaseOrderNumber purchaseOrderDate purchaseOrderDueDatepurchaseOrderCancelDatebarCodeNumberquantityOrderedvendorNumberitemCost

Class Attributes

Video StoreClasses

showing Attributes -Part 3 of 3

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Video Store Attribute Data Dictionary (partial)

Attribute Class Definition/Rules

barCodeNumber Inventory Up to 12 charactersTransaction Up to 12 characters

creditCardExpireDate Member MM/YY (month, year)

creditCardNumber Member Up to 19 characters

cost Inventory range: 0 to 999.99

depositAmount Member min: $25; max: $200

description Inventory 40 characters

employeeNumber Transaction 6 digits

memberAddress Member 30 characters (no P.O. Box)

memberCity Member 30 characters

memberName Member 30 characters

etc.....

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Inventory

Video Store – UML Class Diagram

SaleItem RentalItem

Video Game ConcessionItem VCR

Transaction Employee StoreLocation

SaleTransaction RentalTransaction Suplier

Member PurchaseOrder

SaleRentalLineItemPurchaseOrderLineItem

1

0..*

0..* 0..1 10..*

1..*

1 1

1..*

10..*

1

0..*

11..*

10..*

0..*

1

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Video Store Future Enhancements List - Final Pass

1. Open-ended memberships (indefinite; ie: no cancellations) with C.C. or $50 deposit (P)

2. Establish Bonus Point System for rentals (ie: rent 9 get one rental free, etc.) (E)

3. Handle special orders for videos (E)

4. Ability to reserve a movie ahead of time (E)

5. Automatic billing to credit card at end of month for month's charges (E)

6. Establish a membership DEBIT card (E)

7. Allow a monthly "tab" to be paid at the end of the month (see #5) (E)

8. No physical security devices on videos (P)

9. System will not include Payroll system, Accts. Payable, or Financial systems such as General Ledger and Income Statements (P)

10. The system will not keep information on non-member customer sales (P)

11. Game inventory can be for sale or rent (but only one of these at a time) (P)

12. The system will NOT include any work shift scheduling of employees (P)

13. The Video Store will rent VCRs

14. Payment for Rental transactions will be at time of transaction (not when item returned)

NOTE: (P) = Policy decision (E) = Potential Future Enhancement

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QUITTING TIME