Object Oriented Analysis and Design Using the UML Version 4.2

1、Introduction to Object OrientationObjectives: Introduction to Object OrientationUnderstand the basic principles of object orientation Understand the basic concepts and terms of object orientation and the associated UML notationAppreciate the strengths of object orientation Understand some basic UML

2、modeling mechanismsIntroduction to Object Orientation TopicsBasic Principles of Object OrientationBasic Concepts of Object OrientationStrengths of Object OrientationGeneral UML Modeling MechanismsObject OrientationEncapsulationAbstractionHierarchyModularityBasic Principles of Object OrientationSales

3、personNot saying Which salesperson just a salesperson in general!CustomerProductManages ComplexityWhat is Abstraction?Improves ResiliencyWhat is Encapsulation?Hide implementation from clientsClients depend on interfaceHow does an object encapsulate?What does it encapsulate?Order Processing SystemBil

4、lingOrderEntryOrderFulfillmentManages ComplexityWhat is Modularity?The breaking up of something complex into manageable piecesDecreasing abstractionIncreasing abstractionAssetRealEstateSavingsBankAccountCheckingStockSecurityBondElements at the same level of the hierarchy should be at the same level

5、of abstractionWhat is Hierarchy? Levels of abstractionIntroduction to Object Orientation TopicsBasic Principles of Object OrientationBasic Concepts of Object OrientationStrengths of Object OrientationGeneral UML Modeling MechanismsBasic Concepts of Object OrientationObjectClassAttributeOperationInte

6、rface (Polymorphism)ComponentPackageSubsystemRelationshipsBasic Concepts of Object OrientationObjectClassAttributeOperationInterface (Polymorphism)ComponentPackageSubsystemRelationshipsTruckChemical ProcessLinked ListWhat is an Object?Informally, an object represents an entity, either physical, conc

7、eptual, or softwarePhysical entityConceptual entitySoftware entityA More Formal Definition An object is a concept, abstraction, or thing with sharp boundaries and meaning for an application An object is something that has:StateBehaviorIdentity: ProfessorProfessor Clarka + b = 10ProfessorClark : Prof

8、essorProfessorClarkClass Name OnlyObject Name OnlyClass and Object Name(stay tuned for classes)Representing ObjectsAn object is represented as rectangles with underlined namesBasic Concepts of Object OrientationObjectClassAttributeOperationInterface (Polymorphism)ComponentPackageSubsystemRelationshi

9、psOO Principle: AbstractionWhat is a Class?A class is a description of a group of objects with common properties (attributes), behavior (operations), relationships, and semanticsAn object is an instance of a classA class is an abstraction in that it:Emphasizes relevant characteristicsSuppresses othe

10、r characteristicsa + b = 10ClassCoursePropertiesNameLocationDays offeredCredit hoursStart timeEnd timeBehaviorAdd a studentDelete a studentGet course rosterDetermine if it is fullSample ClassProfessorProfessor Clarka + b = 10Representing ClassesA class is represented using a compartmented rectangleP

11、rofessornameempIDcreate( )save( )delete( )change( )Class NameAttributesOperationsClass CompartmentsA class is comprised of three sectionsThe first section contains the class nameThe second section shows the structure (attributes)The third section shows the behavior (operations)Classes of ObjectsHow

12、many classes do you see?ObjectsClassProfessor SmithProfessor JonesProfessor MellonProfessorThe Relationship Between Classes and ObjectsA class is an abstract definition of an objectIt defines the structure and behavior of each object in the classIt serves as a template for creating objects Objects a

13、re grouped into classesBasic Concepts of Object OrientationObjectClassAttributeOperationInterface (Polymorphism)ComponentPackageSubsystemRelationships:CourseOfferingnumber = 101startTime = 900endTime = 1100:CourseOfferingnumber = 104startTime = 1300endTime = 1500CourseOfferingnumberstartTime endTime

14、ClassAttributeObjectAttribute ValueWhat is an Attribute?Basic Concepts of Object OrientationObjectClassAttributeOperationInterface (Polymorphism)ComponentPackageSubsystem RelationshipsCourseOfferingaddStudent deleteStudentgetStartTimegetEndTimeClassOperationWhat is an Operation?Basic Concepts of Obj

15、ect OrientationObjectClassAttributeOperationInterface (Polymorphism)ComponentPackageSubsystem RelationshipsManufacturer AManufacturer BManufacturer COO Principle:EncapsulationWhat is Polymorphism?The ability to hide many different implementations behind a single interfaceTubePyramidCubeShapeDrawMove

16、ScaleRotateRealization relationship(stay tuned for realization relationships)What is an Interface?Interfaces formalize polymorphismInterfaces support “plug-and-play architecturesTubePyramidCubeShapeDrawMoveScaleRotateTubePyramidCubeShapeElided/Iconic Representation(“lollipop)Canonical (Class/Stereot

17、ype) Representation(stay tuned for realization relationships)Interface RepresentationsBasic Concepts of Object OrientationObjectClassAttributeOperationInterface (Polymorphism)ComponentPackageSubsystem RelationshipsSource FileNameExecutableNameOO Principle:EncapsulationWhat is a Component?A non-trivi

18、al, nearly independent, and replaceable part of a system that fulfills a clear function in the context of a well-defined architecture A component may be A source code componentA run time components orAn executable componentComponentNameComponent InterfaceBasic Concepts of Object OrientationObjectCla

19、ssAttributeOperationInterface (Polymorphism)ComponentPackageSubsystem RelationshipsPackage NameOO Principle:ModularityWhat is a Package?A package is a general purpose mechanism for organizing elements into groupsA model element which can contain other model elementsUsesOrganize the model under devel

20、opmentA unit of configuration managementBasic Concepts of Object OrientationObjectClassAttributeOperationInterface (Polymorphism)ComponentPackageSubsystem RelationshipsOO Principles: Encapsulation and ModularitySubsystem NameInterfaceInterfaceRealizationSubsystem(stay tuned for realization relations

21、hip)What is a Subsystem?A combination of a package (can contain other model elements) and a class (has behavior)Realizes one or more interfaces which define its behaviorComponentNameDesign ModelImplementation ModelComponent NameComponent InterfaceComponent InterfaceOO Principles: Encapsulation and M

22、odularitySubsystems and ComponentsComponents are the physical realization of an abstraction in the designSubsystems can be used to represent the component in the designBasic Concepts of Object OrientationObjectClassAttributeOperationInterface (Polymorphism)ComponentPackageSubsystem RelationshipsRela

23、tionshipsAssociationAggregationCompositionDependencyGeneralizationRealizationProfessorUniversityWorks forClassAssociationAssociation NameProfessorUniversityEmployerEmployeeRole NamesRelationships: AssociationModels a semantic connection among classesStudentScheduleWholeAggregationPartRelationships:

24、AggregationA special form of association that models a whole-part relationship between an aggregate (the whole) and its partsStudentScheduleWholeAggregationPartRelationships: CompositionA form of aggregation with strong ownership and coincident lifetimesThe parts cannot survive the whole/aggregate A

25、ssociation: Multiplicity and NavigationMultiplicity defines how many objects participate in a relationshipsThe number of instances of one class related to ONE instance of the other classSpecified for each end of the associationAssociations and aggregations are bi-directional by default, but it is of

26、ten desirable to restrict navigation to one directionIf navigation is restricted, an arrowhead is added to indicate the direction of the navigationAssociation: Multiplicity2.40.11.*0.*1*UnspecifiedExactly oneZero or more (many, unlimited)One or moreZero or oneSpecified rangeMultiple, disjoint ranges

27、2, 4.6StudentSchedule10.*MultiplicityNavigationExample: Multiplicity and NavigationClientSupplierPackageClientPackageSupplierPackageClientSupplierClassDependency relationshipDependency relationshipComponentRelationships: DependencyA relationship between two model elements where a change in one may c

28、ause a change in the otherNon-structural, “using relationshipRelationships: GeneralizationA relationship among classes where one class shares the structure and/or behavior of one or more classesDefines a hierarchy of abstractions in which a subclass inherits from one or more superclassesSingle inher

29、itanceMultiple inheritanceGeneralization is an “is-a-kind of relationshipAccountbalancenamenumberWithdraw()CreateStatement()CheckingWithdraw()SavingsGetInterest()Withdraw()Superclass (parent)SubclassesGeneralization RelationshipAncestorDescendentsExample: Single InheritanceOne class inherits from an

30、otherAirplaneHelicopterWolfHorseFlyingThingAnimalBirdmultipleinheritanceUse multiple inheritance only when needed, and always with caution !Example: Multiple InheritanceA class can inherit from several other classesInheritance leverages the similarities among classesWhat Gets Inherited?A subclass in

31、herits its parents attributes, operations, and relationshipsA subclass may:Add additional attributes, operations, relationshipsRedefine inherited operations (use caution!)Common attributes, operations, and/or relationships are shown at the highest applicable level in the hierarchyTrucktonnageGroundV

32、ehicleweightlicenseNumberCarownerregister( )getTax( )Person0.*Trailer1Superclass (parent)SubclassgeneralizationsizeExample: What Gets InheritedComponentInterfaceUse CaseUse-Case RealizationElided formClassInterfaceSubsystemInterfaceCanonical formRelationships: RealizationOne classifier serves as the

33、 contract that the other classifier agrees to carry outFound between:Interfaces and the classifiers that realize themUse cases and the collaborations that realize themInBasic Principles of Object OrientationBasic Concepts of Object OrientationStrengths of Object OrientationGeneral UML Modeling Mecha

34、nismsStrengths of Object OrientationA single paradigmFacilitates architectural and code reuseModels more closely reflect the real worldMore accurately describe corporate data and processesDecomposed based on natural partitioningEasier to understand and maintainStabilityA small change in requirements

35、 does not mean massive changes in the system under developmentClass Diagram for the Sales ExampleSalespersonProductSaleCorporateCustomerIndividualTruckVehicleTrainsellerbuyeritem soldshipping mechanismEffect of Requirements ChangeSuppose you need a new type of shipping vehicle .SalespersonProductSal

36、eCorporateCustomerIndividualTruckVehicleTrainsellerbuyeritem soldshipping mechanismChange involves adding a new subclassAirplaneIntroduction to Object Orientation TopicsBasic Principles of Object OrientationBasic Concepts of Object OrientationStrengths of Object OrientationGeneral UML Modeling Mecha

37、nismsMyBoundaryClassMyBoundaryClassStereotypesClassify and extend the UML notational elementsDefine a new model element in terms of another model elementMay be applied to all modeling elementsRepresented with name in guillemets or as a different icon Processor #1DesignClassProcessor #1Example: Stere

38、otypesSample boundary class (stereotype)Stereotype of dependency relationStereotype of These create new symbols using accustomed graphics.There can be up to one MaintainScheduleForm per user session.MaintainScheduleFormNotesA note can be added to any UML elementNotes may be added to add more information to the diagram It is a dog eared rectangle The note may be anchored to an element with a dashed linePersistentClasspersistenceanObject : ClassAlocation=serverTagged