1. Object Oriented Analysis and Design Using the UML
OOADv4.2 Instructor Notes
Object Oriented Analysis and Design Using the UML
Introduction to Object Orientation
PART 1
Module 3 - Introduction to Object Orientation

2. Objectives: Introduction to Object Orientation
OOADv4.2 Instructor Notes
Objectives: Introduction to Object Orientation
Understand the basic principles of object orientation
Understand the basic concepts and terms of object orientation and the associated UML notation
Appreciate the strengths of object orientation
Understand some basic UML modeling mechanisms
In the Best Practices module, we discussed some characteristics common to successful projects. OO facilitates the following best practices:
Develop Iteratively
Model Visually
Use Component Architecture
Defining basic OO terms and concepts allows everyone in the class to start on a level playing field.
Module 3 - Introduction to Object Orientation

3. Introduction to Object Orientation Topics
OOADv4.2 Instructor Notes
Introduction to Object Orientation Topics
Basic Principles of Object Orientation
Basic Concepts of Object Orientation
Strengths of Object Orientation
General UML Modeling Mechanisms
Module 3 - Introduction to Object Orientation

4. Basic Principles of Object Orientation
OOADv4.2 Instructor Notes
Basic Principles of Object Orientation
Object Orientation
Encapsulation
Abstraction
Hierarchy
Modularity
Module 3 - Introduction to Object Orientation

5. OOADv4.2 Instructor Notes
What is Abstraction?
Salesperson
Not saying Which salesperson – just a salesperson in general!!!
Discuss what makes a good abstraction with the students:
Concise,
Represents a single coherent concept,
etc.
Customer
Product
Manages Complexity
Module 3 - Introduction to Object Orientation

6. OOADv4.2 Instructor Notes
What is Encapsulation?
Hide implementation from clients
Clients depend on interface
Encapsulation is putting the “databits” and operations that manipulate them in the same place. Encapsulation DISALLOWS direct manipulation of things that have been encapsulated without utilising the supplied interface.
Another example - the accelerator on a car. You put your foot down and car goes faster - this works on most cars, and you don’t worry about the cables, electronics, engine, etc.
How does an object encapsulate?
What does it encapsulate?
Improves Resiliency
Module 3 - Introduction to Object Orientation

7. OOADv4.2 Instructor Notes
What is Modularity?
The breaking up of something complex into manageable pieces
Modularity supports separation of concerns.
Another example of modularity is a car, which is made up of a body, chassis, engine, wheels, etc.
Order
Entry
Order Processing System
Order
Fulfillment
Billing
Manages Complexity
Module 3 - Introduction to Object Orientation

8. OOADv4.2 Instructor Notes
What is Hierarchy?
Asset
Levels of abstraction
Hierarchy is not an organizational chart.
Hierarchy is not a functional decomposition.
Hierarchy is a taxonomic organization. The use of hierarchy makes it easy to recognize similarities and differences.
For example, in botany, plants are organized into families, chemistry uses a periodic table to organize the elements.
Another example -- telephone number, then a 0800 (free call) number, premium rate number, etc
Decreasing
abstraction
Increasing
BankAccount
Security
RealEstate
Savings
Checking
Stock
Bond
Elements at the same level of the hierarchy should be at the same level of abstraction
Module 3 - Introduction to Object Orientation

9. Introduction to Object Orientation Topics
OOADv4.2 Instructor Notes
Introduction to Object Orientation Topics
Basic Principles of Object Orientation
Basic Concepts of Object Orientation
Strengths of Object Orientation
General UML Modeling Mechanisms
Before moving on, ask the students to name the four basic principles of OO (as a review).
Module 3 - Introduction to Object Orientation

10. Basic Concepts of Object Orientation
OOADv4.2 Instructor Notes
Basic Concepts of Object Orientation
Object
Class
Attribute
Operation
Interface (Polymorphism)
Component
Package
Subsystem
Relationships
Module 3 - Introduction to Object Orientation

11. Basic Concepts of Object Orientation
OOADv4.2 Instructor Notes
Basic Concepts of Object Orientation
Object
Class
Attribute
Operation
Interface (Polymorphism)
Component
Package
Subsystem
Relationships
Module 3 - Introduction to Object Orientation

12. OOADv4.2 Instructor Notes
What is an Object?
Informally, an object represents an entity, either physical, conceptual, or software
Physical entity
Conceptual entity
Software entity
Truck
Chemical Process
Linked List
Module 3 - Introduction to Object Orientation

13. A More Formal Definition
OOADv4.2 Instructor Notes
A 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:
State
Behavior
Identity
Module 3 - Introduction to Object Orientation

14. OOADv4.2 Instructor Notes
Representing Objects
An object is represented as rectangles with underlined names
: Professor
Professor Clark
a + b = 10
ProfessorClark
Class Name Only
ProfessorClark :
Professor
Object Name Only
Class and Object Name
(stay tuned for classes)
Module 3 - Introduction to Object Orientation

15. Basic Concepts of Object Orientation
OOADv4.2 Instructor Notes
Basic Concepts of Object Orientation
Object
Class
Attribute
Operation
Interface (Polymorphism)
Component
Package
Subsystem
Relationships
Module 3 - Introduction to Object Orientation

16. OOADv4.2 Instructor Notes
What is a Class?
A class is a description of a group of objects with common properties (attributes), behavior (operations), relationships, and semantics
An object is an instance of a class
A class is an abstraction in that it:
Emphasizes relevant characteristics
Suppresses other characteristics
A class has been called a “cookie cutter” for objects.
OO Principle: Abstraction
Module 3 - Introduction to Object Orientation

17. OOADv4.2 Instructor Notes
Sample Class
Class
Course
Properties
Name
Location
Days offered
Credit hours
Start time
End time
Behavior
Add a student
Delete a student
Get course roster
Determine if it is full
a + b = 10
Module 3 - Introduction to Object Orientation

18. OOADv4.2 Instructor Notes
Representing Classes
A class is represented using a compartmented rectangle
a + b = 10
Professor
Professor Clark
Module 3 - Introduction to Object Orientation

19. OOADv4.2 Instructor Notes
Class Compartments
A class is comprised of three sections
The first section contains the class name
The second section shows the structure (attributes)
The third section shows the behavior (operations)
In Rose:
You may select which compartments are displayed via Diagram Object Properties for the diagram element.
You may select which items appear in which compartments using the Edit Compartment function for the diagram element.
Professor
name
empID
create( )
save( )
delete( )
change( )
Class Name
Attributes
Operations
Module 3 - Introduction to Object Orientation

20. OOADv4.2 Instructor Notes
Classes of Objects
How many classes do you see?
The answers you get will vary depending on the students’ perspectives on what they see, as well as the criteria they use to organize the objects shown on this slide. For example, some possible answers include:
Two classes: animals and non-animals
Two classes: Extinct and non-extinct things
Etc.
Module 3 - Introduction to Object Orientation

21. The Relationship Between Classes and Objects
OOADv4.2 Instructor Notes
The Relationship Between Classes and Objects
A class is an abstract definition of an object
It defines the structure and behavior of each object in the class
It serves as a template for creating objects
Objects are grouped into classes
This may seem repetitive with earlier slides, but it has been noted that the repetition of the discrimination between objects and classes is beneficial to “newbies”. If this does not apply to your class, you can cover this slide briefly.
Objects
Class
Professor Smith
Professor Mellon
Professor
Professor Jones
Module 3 - Introduction to Object Orientation

22. Basic Concepts of Object Orientation
OOADv4.2 Instructor Notes
Basic Concepts of Object Orientation
Object
Class
Attribute
Operation
Interface (Polymorphism)
Component
Package
Subsystem
Relationships
Module 3 - Introduction to Object Orientation

23. OOADv4.2 Instructor Notes
What is an Attribute?
Object
Class
Attribute
Attribute Value
:CourseOffering
number = 101
startTime = 900
endTime = 1100
CourseOffering
number
startTime
endTime
:CourseOffering
number = 104
startTime = 1300
endTime = 1500
Module 3 - Introduction to Object Orientation

24. Basic Concepts of Object Orientation
OOADv4.2 Instructor Notes
Basic Concepts of Object Orientation
Object
Class
Attribute
Operation
Interface (Polymorphism)
Component
Package
Subsystem
Relationships
Module 3 - Introduction to Object Orientation

25. OOADv4.2 Instructor Notes
What is an Operation?
CourseOffering
addStudent
deleteStudent
getStartTime
getEndTime
Class
Operation
Module 3 - Introduction to Object Orientation

26. Basic Concepts of Object Orientation
OOADv4.2 Instructor Notes
Basic Concepts of Object Orientation
Object
Class
Attribute
Operation
Interface (Polymorphism)
Component
Package
Subsystem
Relationships
Module 3 - Introduction to Object Orientation

27. OOADv4.2 Instructor Notes
What is Polymorphism?
The ability to hide many different implementations behind a single interface
Polymorphism will be addressed in more detail in the Class Design module.
Another example of polymorphism: There is a toddler sitting in front of some blocks and a teenager siting in front of a piano. An adult walks into the room and says “play”. The toddler plays with the blocks and the teenage plays the piano.
Another example - car accelerator on different cars.
Manufacturer A
Manufacturer B
Manufacturer C
OO Principle: Encapsulation
Module 3 - Introduction to Object Orientation

28. OOADv4.2 Instructor Notes
What is an Interface?
Interfaces formalize polymorphism
Interfaces support “plug-and-play” architectures
Interfaces are not abstract classes, as abstract classes allow you to provide default behavior for some/all of their methods. Interfaces provide no default behavior.
Tube
Shape
Draw
Move
Scale
Rotate
<<interface>>
Pyramid
Cube
Realization relationship
(stay tuned for realization relationships)
Module 3 - Introduction to Object Orientation

29. Interface Representations
OOADv4.2 Instructor Notes
Interface Representations
Tube
Elided/Iconic Representation (“lollipop”)
Pyramid
Shape
Cube
Canonical (Class/Stereotype) Representation
Tube
Shape
Draw
Move
Scale
Rotate
<<interface>>
Pyramid
Cube
(stay tuned for realization relationships)
Module 3 - Introduction to Object Orientation