Slide 1 Systems Analysis and Design With UML 2.0 An Object-Oriented Approach, Second Edition Chapter 2: Introduction to Object-Oriented Systems Analysis and Design with the Unified Modeling Language, Version 2.0 Alan Dennis, Barbara Wixom, and David Tegarden © 2005 John Wiley & Sons, Inc.

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Slide 3 Unified Modeling Language, Version 2.0 Chapter 2

Slide 4 Objectives Understand the basic characteristics of object- oriented systems. Be familiar with the basic concepts of the Unified Modeling Language (UML), Version 2.0. Be familiar with the process.

Slide 5 Basic Characteristics of Object Oriented Systems Classes and Objects Methods and Messages Encapsulation and Information Hiding Inheritance Polymorphism and Dynamic Binding

Slide 6 Classes and Objects Class – Template to define specific instances or objects Object – Instantiation of a class Attributes – Describes the object Behaviors – specify what object can do

Slide 7 Classes and Objects

Slide 8 Methods and Messages Methods implement an object’s behavior Analogous to a function or procedure Messages are sent to trigger methods Procedure call from one object to the next

Slide 9 Messages and Methods

Slide 10 Encapsulation and Information Hiding Encapsulation combination of data and process into an entity Information Hiding Only the information required to use a software module is published to the user Reusability Key Use an object by calling methods

Slide 11 Inheritance Superclasses or general classes are at the top of a hierarchy of classes Subclasses or specific classes are at the bottom Subclasses inherit attributes and methods from classes higher in the hierarchy

Slide 12 Class Hierarchy

Slide 13 Inheritance

Slide 14 Polymorphism and Dynamic Binding Polymorphism A message can be interpreted differently by different classes of objects Dynamic Binding Sometimes called late binding Delays typing or choosing a method for an object until run-time Static Binding Type of object determined at compile time

Slide 15 Polymorphish & Encapsulation

Slide 16 The Unified Modeling Language, Version 2.0 In this class we will use UML to describe three viewpoints of the current system and the new system. You will model these viewpoints with Use Cases and Use Case Diagrams Structure Diagrams Behavior Diagrams

Slide 17 Use Cases Use Case Descriptions and Use Case Diagrams are used to describe an external, functional viewpoint of the system. They model the business processes of the current and the new system. The principal question to ask is what information do users of the system give to the system and what information do they receive from it.

Slide 18 Use Case Diagrams Capture Business requirements Illustrate interaction between a system and its environment Includes end user Any external system that interacts with its information system The purpose of the Use Cases is to documents and clarify requirements of the system being modeled Think of Use Cases as the contract between you and the client organization

Slide 19 Structural Modeling Structure Diagrams are used to describe an internal, structural viewpoint of the system Structural Diagrams describe the all the classes, data and methods of the system that will store, process and deliver the information described by the use cases

Slide 20 Behavioral Modeling Behavioral Diagrams are used to describe the internal behavior of the system. The questions to ask is what are the steps required to produce information to the users and how do the objects have to interact in order to deliver it.

Slide 21 Object Oriented Systems Analysis and Design is Use-case driven Architecture Centric An Iterative and Incremental Process

Slide 22 Distribution of Effort Over Planning, Analysis, Design and Implementation Phases

Slide 23 Supporting Workflows

Slide 24 Benefits of the Object Approach

Slide 25 MOOSAD Approach