1 / 11

Object Modeling

Object Modeling. J. Stephen Schiavo Missouri Southern State University. Object Modeling. Definition Concepts Objects, attributes, methods, encapsulation Classes, generalization, specialization Object/class relationship Messages Polymorphism Modeling process. Definition.

xantha-beck
Download Presentation

Object Modeling

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Object Modeling J. Stephen Schiavo Missouri Southern State University

  2. Object Modeling • Definition • Concepts • Objects, attributes, methods, encapsulation • Classes, generalization, specialization • Object/class relationship • Messages • Polymorphism • Modeling process

  3. Definition • Object-Oriented Analysis & Design:The application of objects to understanding existing systems, and in specifying new or improved systems • Object Modeling:Technique for identifying objects in the system and the relationships among them

  4. Concepts • Objects: Entities in the environment, capable of being seen, touched, sensed; and of experiencing events. • Attributes: characteristics of objects • Behavior(s): Things an object can do, or you can do to an object: methods • Encapsulation: packaging attributes and methods together in the object.

  5. Concepts … • Classes: set of objects with common attributes and behaviors. • Retail Stores, Students, Vehicles, … • Generalization: gathering common aspects of similar classes to form a super-type • Specialization: distinguishing one instance of a class by adding or modifying attributes or methods to create a subtype.

  6. SSN, Name, Addr, Phone; Employee:Dep, Sal, Ins Faculty:Ten, TrmDeg Students:Maj, Advr, Hrs Admin’r:Level, Vac Classes / Sub & Super Classes

  7. Concepts … • Object/class relationships:Natural relationship among classes, just as in the entity-relationship data model • Messages: How one object interacts with, i.e, how it calls or uses another object • Polymorphism: Behaviors of the same name can differ markedly with objects.“Shut” is a different action for objects door, window, suitcase, drawer, faucet, mouth.

  8. verb Modeling process What do these look like?(Figure 8.8) • Identifying objects • Use case (‘yooss’ case)modeling – scenarios • Use case: sequence of steps in a task • Actor: anything interacting with system;a user or role; internal, or external • Organizing objects and relationships • Object Association Model

  9. Identifying objects • Identify actors (people, places, & things) and use cases (transactions) • Constructing the use casemodel diagram:Which actors involved in which cases • Documenting use case course of events • Name the initiating actor • Generally describe the transaction • Step-by-step process through typical case • Pre-and-post conditions (before and after case) • Assumptions: performance, security, etc. Figure 8.9

  10. Identifying objects … • Identifying use case dependencies showing which case must follow which • Document alternative course of events for non-typical situations: an order from a credit-impaired client; booking a flight for a disabled person or for a VIP ( or for a disabled VIP!) … • Finding potential objects, selecting objects: remove duplicates (synonyms), actors outside the system, non-unique actors, etc…

  11. Organizing objects and relationships • Identify associations and multiplicity:what one object needs to know about or do to (or do with) another object • Identifying generalizations and specializations … subtypes/super-types … as in person  employee  manager • Identifying aggregation relationships(is part of …), e.g., Truck  cab & trailer • Preparing the object association model(Figure 8.16) What does this remind you of?

More Related