RE The OO Solution MDE SE

CSE870: Cheng

CSE870: Advanced Software Engineering (Cheng) 1

MDERE

SE

• The OO model closely resembles the problem domain– Base your model on the objects in the

problem domain• Iteratively refine the high-level model

until you have an implementation– Attempt to avoid big conceptual jumps

during the development process

CSE870: UML Classes 1

The OO Solution

MDERE

SEObjects


J. Q. Public

VISA

123 4567 887766 998

J. Q. Public

Drivers LicenseState of Michigan

A-12345603-12-63

CSE870: Cheng


MDERE

SE

J. Q. Public

VISA

123 4567 887766 998

J. Q. Public

Drivers LicenseState of Michigan

A-12345603-12-63

Person objects

Card objectsAttributes

heightwidthid-number

Operationsissuechange

Card class

Person classAttributes

nameageheightweight

Operationsmovechange-job

abstracts to

Attributes and Operations


MDERE

SE

• Identity– Discrete and distinguishable entities

• Classification– Abstract entities with the same structure (attributes) and

behavior (operations) into classes• Polymorphism

– The same operation may behave differently on different classes• Inheritance

– Sharing of attributes and operations based on a hierarchical relationship


Characteristics of Objects

CSE870: Cheng


MDERE

SE

The Class Diagrams


MDERE

SE

• Something that makes sense in the application context (application domain)– J.Q. Public– Joe’s Homework Assignment 1– J. Q. Public’s drivers license

• All objects have identity and are distinguishable

• NOT objects– Person– Drivers license


Objects

CSE870: Cheng


MDERE

SE

• Describes a group of objects with:– similar properties (attributes), – common behavior (operations), – common relationships to other classes, and – common semantics

• Person• J. Q. Public• Joe Smith• D. Q. Public

– Card• Credit card• Drivers license• Teller card


Classes

MDERE

SE Class Diagrams


Class with attributes Objects with values

Objects have an identity

Do not explicitly list object identifiersSSN OK!

Class diagram Instance diagram

age: integer

Person D. Q. Public:

age= 32

Person J. Q. Public:

age= 35

Person

CSE870: Cheng


MDERE

SE Examples


MDERE

SEOperations and Methods

• Transformation that can be applied to or performed by an object

• May have arguments


CSE870: Cheng


MDERE

SE Object Notation - Summary


MDERE

SE

• Conceptual connection between classes– A credit card is issued-by a bank– A person works-for a company


Associations

Class diagrams

Credit Card BankIssued-by

Person CompanyWorks-for

J.Q. Public:

Age=35

Person Michigan State Univ:Company

Works-for Instance diagram

CSE870: Cheng


MDERE

SE

• There is no direction implied in an association (Rumbaugh - OMT)


Associations are Bi-directional

Countryname

Drivers-licenselic.-number: integer

Personname

Cityname

Has-capital

Is-issued

MDERE

SE

• Unified adds a direction indicator– Inconsistently used


Associations Can Have Direction

Countryname

Drivers-licenselic.-number: integer

Personname

Cityname

Has-capital

Is-issued

CSE870: Cheng


MDERE

SE

• One object can be related to many objects through the same association


Multiplicity

One person holds one credit card name: String

Person

card-number: integer

Credit-cardHolds

One person can hold zero or more credit cards name: String

Person


Credit-cardHolds 0..*

MDERE

SEMultiplicity (Cont.)


•One person can hold zero or more credit cards (0..*) •Each card has zero or one holder (0..1)

name: Stringage: integer

Person


Credit-cardHolds 0..*0..1

Holds

Holds

:JQPublic:Person

name= J. Q. Publicage=35

:DQPublic:Person

name= D. Q. Publicage=32

card-number=123 456 789

Card789:Credit-Card

card-number=111 222 333

Card123:Credit-Cardcard-number=444 555 666

Card456:Credit-Card

CSE870: Cheng


MDERE

SE

• Ternary association– Project, language, person

• Seldom needed (and should be avoided)


Higher order associations

Language

Person

Project1..*

1..*

1..*

J. Q. Public:PersonAge=35

Compiler: ProjectC++ :Language

TicTacToe:ProjectLISP:Language

Instance of ternaryassociation

MDERE

SE

• Associations can have properties the same way objects have properties


Link Attributes

How to represent salary and job title?name: String

age: integerSSN: integer

address: String

Person

name: Stringaddress: String

CompanyWorks-for0..*

Use a link attribute!name: Stringage: integerSSN: integer

address: String

Person



salary: integerjob-title: String

CSE870: Cheng


MDERE

SEFolding Link Attributes


Why not this?

Salary and job title are properties of the job notthe person

In this case, a link attribute is the only solution

name: Stringage: integerSSN: integer

address: Stringsalary: integerjob-title: String

Person




address: String

Person




0..*

MDERE

SE

• Attach names to the ends of an association to clarify its meaning


Role Names


address: String

Person


CompanyWorks-for0..* 0..*


employeremployeeboss

workerManages0..*

0..1

CSE870: Cheng


MDERE

SE

• A special association, the is-part-of association– A sentence is part of a paragraph (a

paragraph consists of sentences)– A paragraph is part of a document (a

document consists of paragraphs)


Aggregation

Aggregation symbol

Document Paragraph Sentence0..* 0..*

MDERE

SE

• Often used in parts explosion


Aggregation (Cont.)

Car

Wheel Body Gearbox Engine

Door Hood Trunk Piston Valve Crankshaft

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

4

CSE870: Cheng


MDERE

SE Generalization and Inheritance

• The is-a association– Cards have many

properties in common– Generalize the common

properties to a separate class, the base-card

– Let all cards inherit from this class, all cards is-a base-card (plus possibly something more)


issue()revoke()

height: integerwidth: integer

thickness: integerid-number: integer

Card

expire()

class: vehicleissued: dateexpires: date

Drivers License

expire()

issued: dateexpires: date

ID Card

validate()

credit-limit: integerissued: date

Credit Card

MDERE

SE

name

City

name

Airline

namelicense

Pilot

name

Passenger

heat()clean()

name

Airport

cancel()delay()

dateflight #

Flight

heat()refuel()clean()

modelserial #

hours flown

Plane

reserve()

locationSeat

Based-In 0..*

Departs

Works-for

Arrives Used-For

Certified-On

Owns

Located-In

0..*

OffersPilots

Confirmed-for

0..*

0..*

0..*

1..*

0..*

0..*0..*

0..*

30..*

Example


CSE870: Cheng


MDERE

SE

• Can you use the phrase is-part-of or is-made-of• Are operations automatically applied to the parts

(for example, move) - aggregation• Not clear what it should be……


Aggregation Versus Association

Company DepartmentDivision

Person

0..*Works-for

0..* 0..*

MDERE

SEAggregation Versus Inheritance

• Do not confuse the is-a relation (inheritance) with the is-part-of relation (aggregation)

• Use inheritance for special cases of a general concept

• Use aggregation for parts explosion


Car

Wheel

Body

Gearbox

Engine

4

Minivan Compact Jeep

Roll Bar

CSE870: Cheng


MDERE

SE

• A recursive aggregate contains (directly or indirectly) an instance of the same kind of aggregate


Recursive Aggregates

Program

SimpleStatement

CompoundStatement

Block0..*

MDERE

SE

CSE 435: Software Engineering

Class diagram Metamodel I

Eclipse.org

CSE870: Cheng


MDERE

SE


Class diagram Metamodel II

Science direct

MDERE

SE


Use Case Metamodel I

Image: Science Direct: ``Visual Modeling for Software Intensive Systems, Kooper et al, 2006.

uu: use case association relationship_i: includes_e: extends_g: generalization

aa: actor relationshipau: actor-use case relationship

CSE870: Cheng


MDERE

SE


Use Case Metamodel II

Image: Jot.fm

MDERE

SEMeta Model Architecture

• M3: language for describing meta-models (MOF: Meta Object Facility)

• M2: meta model for a given modeling language

• M1: class diagram

• M0: instance of class diagram


M3

M2

M1

M0

CSE870: Cheng


MDERE

SE

• Facebook: • http://upload.wikimedia.org/wikipedia/co

mmons/c/c6/Facebook_Metamodel_Represented_in_UML_notation_v01.jpg


Interesting/Fun Metamodels


CSE870: Cheng



https://commons.wikimedia.org/wiki/File:Me tamodel_Linkedin.jpgBy Jean-Marie Favre, LIG, University of Grenoble (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], v ia Wikimedia Commons

Meta model for LinkedIn

MDERE

SEObject Modeling Summary

• Classes– Name– Attributes– Operations

• Associations– Roles– Link attributes

• Aggregation• Inheritance


Documents

RE The OO Solution MDE SE