OO实例教学课件

WhatisObject-Oriented?

•Objectorientationisanapproachto

softwaredevelopmentthatorganizesboth

theproblemanditssolutionasacollection

ofdiscreteobjects;

•Itisakindofrepresentationthatdescribe

object'sdatastructureandbehavior.

•Itisakindofmodelingtechnology.

Characteristicsof00Representation

•Identity-name,reference,handle

•Abstraction

•Classification

•Encapsulation

•Inheritance

•Polymorphism

•Persistence

The00DevelopmentProcess

•Beconsistencyofterminologyandof

-Theproblemandthesolutionweredescribedin

sameterms:classes,objectsmethods,attributes,and

behaviors.

•Beconsistencyofperspective

-Staticviews

-Dynamicviews

-Restrictions

TendencyforChangewhenUsing00Paradigm

(Jacobsonetal.1995)

Characteristicofsoftwareproduct/projectProbabilityforchange

ObjectsderivedfromtheapplicationLow

Long-livedinformationstructuresLow

Passiveobject5sattributeMedium

SequencesofbehaviorMedium

InterfacewiththeoutsideworldHigh

FunctionalityHigh

OORequirements

•OOrequirementsanalysisisusuallydoneintheuser's

language.

•OOrequirementsanalysisdiscussestheconceptsand

scenarioslikelyinapplicationdomain.

-Theconceptsincludeinformation,service,and

responsibilities.

-Domainknowledgeenablesbothdevelopersandusersto

understandtheproblems.

•Therequirementsdefinitioncanbeindependentof

implement.

00Design

•Requirementspecification,thefirststepsofdesign.

•Torepresentasystemdesign

-First,toidentifyandrepresentclassesandobjects.

-Second,toidentifytheinteractionsandrelationships

amongobjectsandclasses.

•Associations

•Compositions

•Aggregations

•Inheritance

•Toprovidethedetailsinprogramdesign.

-Insertcomputationalfeaturesinthemodels

-Insertsomeclasslibrarydetails

-Considernonfunctionalrequirements

UseCases（用例）

•Describeparticularfunctionalitytoexhibithow

auser,externalsystem,andotherentitydialog

withthesystem.

•Scenario场景

•Script脚本

Usecasediagrams（用例图）

•Actor（角色）

-Aentityinteractingwiththesystem

-Orarolethatanentityplayswithrespectofthesystem

,User

•Device

,Anothersystem

•Cases（用例）

-Adepictionofsomeaspectoffunctionality

•Extensions

-Toextendausecasetoillustrateadifferentordeeper

perspective.

•Uses

-Actuallyareuseofanalready-definedusecase

Overviewofroyalservicestation

Aactoro

Standfbracase

(Billing^)

Customer\

\

(^^efiielmg^)(^^arking^JMaintenance

Firstextensiontoincludepreventivemaintenance

Secondextensiontoincludecreditcardsystem

Thirdextensiontoincludeinventoryandaccounting

FuelOrderingPartsOrdering

systemsystem

UseUMLtoRepresent00

•OMG(ObjectManagementGroup)haveadopted

UMLasthe00notationalstandard.

•UMLcanbeusedtovisualize,specify,or

documentaproblem.

•UMLcanbeusedthroughoutthesoftware

developmentprocess.

UMLdiagrams

•Staticviewisdepictedwith

-Usecases（用例图）

-Classdiagrams（类图）

-Packagediagrams（包图）

-Deploymentdiagrams（酉己置图）

•Dynamicviewisdepictedwith

-Statediagrams（状态图）

-Activitydiagrams（活动图）

-Sequencediagrams（顺序图）

-Collaborationdiagrams（合作图）

•Restrictionsandformalization

-BeexpressedwithOCL（objectconstraintlanguage）

00SystemDesign

•Fivelevelsof00design

-Identifysubjects

-Identifyclassesandobjects

-Identifyattributes

-Identifystructures

-Identifyservices

Determinecandidateclasses

•Somequestionscanhelpustogroupthe

candidateclassesandobjects.

-Whatneedstobe"processed“insomeway?

-Whatitemshavemultipleattributes?

-Whendoyouhavemorethanoneobjectinaclass?

-Whatisbasedontherequirementthemselves,not

derivedfromyourunderstandingofthe

requirements?

-Whatattributesandoperationsarealwaysapplicable

toaclassorobject?

RelatedRequirementStatements

Acustomerhastheoptiontobebilledautomaticallyatthetimeof

purchase(offuel,maintenance,orparking)ortobesentamonthly

paperbill.Ineithercase,customerscanpayusingcash,creditcard,

orpersonalcheck.RoyalServiceStationfuelissoldaccordingto

pricepergallon,dependingonwhetherthefuelisdiesel,regular,or

premium.Serviceispricedaccordingtothecostofpartsandlabor.

Parkingissoldaccordingtodaily,weekly,andmonthlyrates.The

pricesfbrfuel,maintenanceservices,parts,andparkingmayvary;

onlyManny,thestationmanager,canenterorchangeprices.Athis

discretion,Mannymaydesignateadiscountonpurchasefbra

particularcustomer;thisdiscountmayvaryfromonecustomerto

another.A5%localsalestaxapplestoallpurchase.

TentativeclassesofRoyalServiceStation

•Personalcheck•Services

•Paperbill•Discounts

•Creditcard•Tax

•Customer•Parking

•Stationmanager•Maintenance

•Purchase•Cash

•Fuel•Prices

FirstGroupingofAttributesandClasses:Stepl

ClassesAttributes

CustomerPersonalcheck

MaintenanceTax

ServicesPrice

ParkingCash

FuelCreditcard

PaperbillDiscounts

Purchase

Stationmanager

RelatedRequirementStatements

Thesystemappliesonlytoregularrepeat

customers.Aregularrepeatcustomermeansa

customersidentifiedbyname,addressandbirth­

datewhousesthestation'sserviceatleastonce

permonthfbratleastsixmonths.

Thesystemwillsendperiodicmessagesto

customers,remindingthemwhentheirvehicles

areduefbrmaintenance.Normally,maintenance

isneededeverysixmouths.

FirstGroupingofAttributesandClasses:Step2

ClassesAttributes

CustomerPersonalcheck

MaintenanceTax

ServicesPrice

ParkingCash

FuelCreditcard

PaperbillDiscounts

PurchaseBirthdate

PeriodicmessageName

StationmanagerAddress

Forthefullsetofrequirements,we

mightexpandourtabletoinclude

alloftheclasses.

FirstGroupingofAttributesandClasses:Step3

ClassesAttributes

Customer

MaintenancePersonalcheck

ServicesTax

Parking

FuelPrice

Paperbill

PurchaseCash

Periodicmessage

StationmanagerCreditcard

Warningletter

PartsDiscounts

Accounts

InventoryBirthdate

CreditcardsystemName

Part-orderingsystem

Fuel-orderingsystemAddress

IdentifyBehavior

•Lookfbrparticularitemsthatsuggestbehaviors:

(Extractverbsfromtherequirementsstatement)

-Imperativeverbs

-Passiveverbs

-Actions

-Thingsorremindedevents

-Roles

-Operatingprocedures

-Serviceprovidedbyanorganization

•Thebehaviorswillbecomeactionsor

responsibilities.

UseUMLtodescribetherelationship

amongtheobject,classes,andbehaviors

bill

Issuedate:Date

Paymentdate:Date

Price()

Taxes()

Customers()

Purchase()

Add_to_bill(customer,amount,date)

Inheritance

Fourkindsofrelationship

•Generalization

•Aggregation

•Association

•composition

UMLnotations

association

composition

aggregation

dependency

navigation

Associationofclasses

Qualifiedassociation

Qualifiedassociation

SwayBackandForth

•AbstractaMessageClassfromwarningletterand

periodicmessage.

•Thefuelclassshouldbeconnectedtoinventoryclass

•Deletetheaccountclass(hasonlyoneattribute)andadd

theaccountnumbertothecustomerclass.

•Addthreenewclass,refuel,parkingspace,service.

-Fortakingadvantageofthepolymorphism

•Thepriceanddiscountcanbedifferentdependingonwhatserviceis

required.

-Removethediscountratefromthefuelclassandputitinthe

partclass.

-Removethepricefromthefuelclassandaddittotherefuel

class.

-Putthepriceofaparkingspace,locationintheparkingclass.

CustomerPeriodic

Messages

nameWarningletter

Address

Birthdatetexttext

Purchase

dateBillStation

CreditCardManager

systemtaxrateissuedate

Paymentdate

Services

ParkingSpacepriceVehicleMaintenance

locationdiscountrateissuedate

Paymentdate

Refuel

Part

gallons£7Inventory◊

ocationricepartnumber

price

Price

ParksFueldiscountrate

FuelOrderingOrdering

min_quantity=l00systemsystem

Currentquantity

SwayBackandForth

•DeleteStationManagerclass

•Addservicestationtohandlethetrackingof

dormantaccounts

OtherUMLDiagrams

•Classdescriptiontemplate

•Packagediagrams

•Sequencediagrams

•Collaborationdiagrams

•Statediagrams

•Activitydiagrams

Classdescriptiontemplate

•Templatetellus

-thepositionoftheclassintheoverallhierarchy

-exportcontrols

-cardinality

-associations

•Templatealsospecifies

-theoperationsintheclass

-thepublicinterfacetotheclass

Templatefbrtherefuelclass

Classname:refuelPublicinterface:

Category:serviceOperation:

Externaldocuments:price

Exportcontrol:PublicPrivateinterface:

Cardinality:nAttributes:

Hierarchy:Gallons

Super-classes:servicesprice

Associations:Implementation:

Operationname:priceAttributes:

Publicmemberof:refuelGallons

Documentation:price

Preconditions:Statemachine:no

Gallons>0

Objectdiagram:unspecifiedConcurrency:sequential

Semantics:Persistence:transient

final_price=gallons*price

Concurrency：sequential

Packagediagrams

Standfor

dependent

Interactiondiagrams

•Todescribehowoperationsandbehaviors

arehandledbyobjects.

•Todescribehowtheobjectsareconnected

statically.

•Basedoneachusecase

•Twokindsofinteractiondiagrams

-Sequencediagrams

-Collaborationdiagrams

Sequencediagramfbrtherefuelusecase

CustomerServiceStationCreditCardPurchaseRefuel

System