合肥工业大学：《软件工程》课程教学资源（PPT课件讲稿）OO实例

What is object-Oriented? Object orientation is an approach to software development that organizes both the problem and its solution as a collection of discrete objects It is a kind of representation that describe objects data structure and behavior It is a kind of modeling technology

What is Object-Oriented? • Object orientation is an approach to software development that organizes both the problem and its solution as a collection of discrete objects; • It is a kind of representation that describe object’s data structure and behavior. • It is a kind of modeling technology

Characteristics of oo representation Identity--name, reference, handle abstraction Classificatio Encapsulation Inheritance Polymorphism Persistence

Characteristics of OO Representation • Identity—name, reference, handle • Abstraction • Classification • Encapsulation • Inheritance • Polymorphism • Persistence

The oo development process be consistency of terminology and of The problem and the solution were described in same terms: classes, objects methods, attributes, and behaviors Be consistency of perspective Static views Dynamic views -Restrictions

The OO Development Process • Be consistency of terminology and of –The problem and the solution were described in same terms : classes, objects methods, attributes, and behaviors. • Be consistency of perspective –Static views –Dynamic views –Restrictions

Tendency for Change when Using OO Paradigm (Jacobson et al. 1995) Characteristic of software product/project Probability for change Objects derived from the application Long -lived information structures LOw Passive object's attribute Medium Sequences of behavior Medium Interface with the outside world H 1gh Functionality High

Tendency for Change when Using OO Paradigm (Jacobson et al. 1995) Characteristic of software product/project Probability for change Objects derived from the application Low Long-lived information structures Low Passive object’s attribute Medium Sequences of behavior Medium Interface with the outside world High Functionality High

Oo Requirements OO requirements analysis is usually done in the users language Oo requirements analysis discusses the concepts and scenarios likely in application domain The concepts include information, service, and responsibilities Domain knowledge enables both developers and users to understand the problems The requirements definition can be independent of Implement

OO Requirements • OO requirements analysis is usually done in the user’s language. • OO requirements analysis discusses the concepts and scenarios likely in application domain. – The concepts include information, service, and responsibilities. – Domain knowledge enables both developers and users to understand the problems. • The requirements definition can be independent of implement

OO Design Requirement specification the first steps of design To represent a system design First, to identify and represent classes and objects Second to identify the interactions and relationships among objects and classes associations · Compositions Aggregations Inheritance To provide the details in program design Insert computational features in the models Insert some class library details Consider nonfunctional requirements

OO Design • Requirement specification, the first steps of design. • To represent a system design – First, to identify and represent classes and objects. – Second, to identify the interactions and relationships among objects and classes. • Associations • Compositions • Aggregations • Inheritance • To provide the details in program design. – Insert computational features in the models – Insert some class library details – Consider nonfunctional requirements

Use cases(用例) Describe particular functionality to exhibit how a user, external system, and other entity dialog with the system Scenario场景 Script脚本

Use Cases (用例） • Describe particular functionality to exhibit how a user, external system, and other entity dialog with the system. • Scenario 场景 • Script 脚本

Use case diagrams(用例图) Actor(角色) a entity interacting with the system Or a role that an entity plays with respect of the system User · Device · Another systen Cases(用例) a depiction of some aspect of functionality Extensions To extend a use case to illustrate a different or deeper perspective Uses Actually a reuse of an already-defined use case

Use case diagrams（用例图） • Actor（角色） – A entity interacting with the system – Or a role that an entity plays with respect of the system • User • Device • Another system • Cases（用例） – A depiction of some aspect of functionality • Extensions – To extend a use case to illustrate a different or deeper perspective. • Uses – Actually a reuse of an already-defined use case

Overview of royal service station a actor Stand for a case Billing Services Customer Refueling g Parking)Maintenance

Overview of royal service station Billing Services Refueling Parking Maintenance Customer Stand for a case A actor

First extension to include preventive maintenance Pa arkin Refueling Customer Ma anager Maintenance extends Preventive Maintenanc

First extension to include preventive maintenance Preventive Maintenance Maintenance Parking Refueling Customer Manager extends