This document discusses object modeling and class identification in software engineering. It covers: 1. The activities involved in object modeling including object identification, Abbott's technique, and identifying entity, boundary, and control objects. 2. The steps of object modeling including class identification, finding attributes, operations, and associations between classes. 3. Approaches to class identification including application domain, syntactic, design patterns, and component-based approaches. 4. Types of objects including entity, boundary, and control objects.

1. introductionto software engineering Prof. BerndBrueggeChapter 5 – Analysis: ObjectModellingMurat Hacioglu

2. OutlineLastLecture : FunctionalModellingNow: ObjectModelling

3. ObjectModellingActivitiesduringobjectmodelling,ObjectIdentification,Abott’sTechniqueTypes: Entity, BoundaryandControlObjects,

4. scenario -> usecase -> object

5. steps of objectmodellingClassidentificationFundamentalassumtionsthatwe can findabstractions.FindingtheattributesFindingtheoperationsFindingtheassociationsbetweenclassesOrder of thesteps is secondary.Goal is gettingdesiredabstraction.

6. steps of objectmodellingMaingoal is findingtheimportantabstraction. Whenwefindthewrongabstractions : Iteratethenrenamethem.Revisethe model.Youwillneverfreezeyourrequirements.Youwillchangerequest.You can do an anotherreview.

7. classidentificationHelpstoidentifytheimportantentities of a systemForwardEngineeringFindtheclassesfor a new software systemReverseEngineeringIdentifytheclasses in an existingsystem.

8. CLASS IDENTIFICATION APPROACHESApplication domain approachSyntacticapproachAnalyzethetexttoidentifytheobjectsDesignpatternsapproach (nextweek)Identifyrelevantabstractions. Ex: Chessgame, bishop, queen.. like software pattern.Component – basedapproachIdentifyexistingsolutionclasses.

9. ClassidentificationproblemsDefinition of thesystemboundaryActorsareoutsidethesystemClassesandObjectsare inside thesystem.FindingtheclassesandobjectsTheapplciation domain has to be analyzed.Differentobjects has to be founddepending on systempurpose.Identifyingthepurpose is another problem.

10. Types of objectsEntityObjectsRepresentpersistentinformationtrackedbythesystem. Ex: Databases.BoundaryObjectsInteractionbetweenuserandsystem. Ex: microfon (PC microphone, Lapelmicrophone)ControlObjectsControltasksto be performedbythesystem.

11. 2bwatch modellingYear<<Entity>>Button<<Boundary>>MonthChangeDate<<Control>>LCDDisplayDayBoundaryControlEntity

12. icons can identifystereotypeWe can skipone of this 3 models.SystemBoundary

13. GraphicsforstereotypeDevelopers can understand UML diagrams.Customer can understandgraphicseasily.Sowearepeelingoffgraphicstodiagrams.This is pros&cons of graphics.Weseethat UML is an extensiblelanguage.

14. ObjecttypesdealwithdifferentchangesHaving 3 types of objectleadsto model thatarestrongertochanges.Interface of a systemchangesmorethancontrolControlchangesmorethanentities in application domain.Objecttypesoriginated in Objective C (MVC)Model -> EntityObjectView -> BoundaryObjectController -> ControlObjectObserverpattern is a specialkind of MVC (willsee in nextweek)

15. Abbott’sTechniquePick a usecaseandlook at flow of events Do textualanalysis Nounsareobjects /classesVerbsareoperationsAfterobject/classesarefoundidentfytheirtype.Real worldentities (FieldOfficer  EntityObject)Real worldprocedures (Emergency Plan  ControlObjectsInterfaceartifacts (PoliceStation  BoundaryObjects)50 yearsagoeveryvillage has a policestation but now not.Monopoly is a board game.Monopoly : subclassBoard game: superclassis a / neithernor / eitherorshowsinheritance

17. HowtofindobjectSyntacticalinvestigationwithAbbot’stechnique.UseothersourcesApplicationknowledge: Endusersandexpertsknow.Solutionknowledge: Abstraction in thesolution domain.General worldknowledge: Ourgenericknowledge.

18. GeneratingclassdiagramsClassidentificationIdentification of attributesandoperationsIdentification of associationsbetweenclassesIdentification of multiplicitiesIdentification of rolesIdenfication of inheritance.

19. whousesclassdiagramsDescription of thestaticproperties of a system.Application domain expert: Usesclassdiagramto model theapplication domain.Developer: Usesclassdiagramsduringsystemdevelopment. Analysis, systemdesign, objectdesignandimplementation.Clientsandendusersareusually not interested in classdiagrams.Functionality of a system.

20. DynamicModelling– Wherearewe?