Introduction to ObjectOriented Analysis and Design

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Introduction to Object-Oriented Analysis and
Design

• Chapter 2

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Learning Objectives

• 4. Explain the basic characteristics of
  object-oriented systems
  
• 5. Explain the Unified Process
• 6. Explain encapsulation, polymorphism, and
  inheritance

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Key Definitions

• Object-oriented techniques view a system as a
  collection of self-contained objects which
  include both data and processes.
  
• The Unified Modeling Language (UML)
• the object modeling standard
• adds a variety of techniques to the field of
  system development.

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THE OBJECT APPROACH AND UML
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Object Concepts/Characteristics

• An object is a person, place, event, or thing
  about which we want to capture information.
  
• Each object has properties (or attributes).
• The state of an object is defined by the value of
  its properties and relations with other objects
  at a point in time.
  
• Objects have behaviors -- things that they can do
  -- which are described by methods (or
  operations).
  
• Objects do not use primary or foreign keys,
  instead each instance is assigned a unique
  identifier (UID) when it is created.

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An Object and Object Instances
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Class

• A class is a general template we use to define
  and create specific instances or objects.

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Classes and Objects
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Class Hierarchy
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Messages

• Messages are information sent to objects to
  trigger methods

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Encapsulation

• The message is sent without considering how it
  will be implemented
  
• The object can be treated as a black-box

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Inheritance

• Classes are arranged in a hierarchy
• Superclasses or general classes are at the top
• Subclasses or specific classes are at the bottom
• Subclasses inherit attributes and methods from
  the superclasses above them
  
• Classes with instances are concrete classes
• Abstract classes only produce templates for more
  specific classes

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Inheritance
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Polymorphism

• The same message can be interpreted differently
  by different classes of objects

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Polymorphism
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Unified Modeling Language - UML
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Unified Modeling Language - UML

• Defines a set of 14 object diagramming techniques
  (we will learn only 4)
  
• 2 major groupings structure and behavior
• Diagrams are tightly integrated syntactically and
  conceptually to represent an integrated whole
  
• Application of UML can vary among organizations

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Structure Diagrams

• Class Diagrams
• Object Diagrams
• Package Diagrams
• Deployment Diagrams
• Component Diagrams
• Composite Structure Diagrams

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Behavior Diagrams

• Activity Diagrams
• Sequence Diagrams
• Communication Diagrams
• Interaction Overview Diagrams
• Timing Diagrams
• Behavior State Machines
• Protocol State Machines
• Use Case Diagrams

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Object Oriented Analysis and Design and the
Unified Process
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Object Oriented Analysis and Design

• Use Case Driven
• Use cases are the primary modeling tool
• Architecture Centric
• The software architecture drives the
  specifications, construction, and documenation
  
• Iterative and Incremental
• Continuous refinement

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Unified Process (similar to the four steps of
SDLC)

• Phases
• Inception
• Similar to Planning phase
• Elaboration
• Similar to Analysis and Ddesign phase
• Construction
• Combines end of Ddesign phase with beginning of
  Implementation
  
• Transition
• Testing and deployment of the Implementation
  phase
  

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Workflows (Engineering)

• Business modeling
• Requirements
• Analysis
• Design
• Implementation
• Test
• Deployment

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Workflows (Supporting)

• Configuration and change management
• Project management
• Environment

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Adaptation of the Phased Development Method
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