1 Introduction to Object Orientation (OO) & Related Terminology zIn a non-programming specific way, orient ourselves to the principles and related terminology.

1

Introduction to Object Orientation (OO) &

Related Terminology

In a non-programming specific way, orient ourselves to the principles and related terminology to OO development

Identify KEY OO Terms

2

GOALS...

TO understand prevailing methodology & related principles

To match relevant programming terminology to OO principles

3

Development in VB:

Given a problemStarted CodingAsked Questions on What

you were Supposed to do !!!Made Major changes to your

programsSome testing...

4

...Development in VB:

Asked for me to Grade itWhite Elephant(Major) modificationsFinally Done !!!

5

...Development in VB:

Then, the Next project followed the same paradigm with little reuse of prior code

6

VB Terms:

Variables

Events

Subroutines

7

Development in Java:

Remember how I required you to code the File I/O projects ?

Structures Separate code module

routines to open, read and write File I/O

Display data on a form To/From Structures

8


In General, we separated the Display (GUI) from the Data Gathering from the Data

Modifications

9


Furthermore, In the Code Modules we attempted to Separate the processing from the Displaying as the Code Modules should make NO reference to the controls on the form

(textboxes, labels, etc)

10


In theory, we could have taken your Code module and used it for other programs without:

Knowing or Caring how the data was processed, modified or Displayed

11

Now in Java we WILL…

Given a problem

UNDERSTAND the problem

Break the problem up into manageable pieces

12


Identify the relevant functions that each piece needs to perform

Create the variables necessary to maintain the STATE of each “piece”

13


Identify how each “piece” will communicate

Develop the main program driver that will control the process (except for event drivenProjects)

14


Test, debug and modify

Asked for me to Grade it

Done !!!

15

Java Terms:

Attributes

Events

Methods

16

In our File I/O project, we can write the following methods:

Open a file Process a file Update a file Close a file

17

In our File I/O project, we can write the following methods:

Read data from the user (console)

Send data to the user (console)

These methods will be able to be reused for any other project that requires Retrieving / Sending data

18

Old School Development:

Set up separate phone lines FOR EACH person you wish to talk to

Wasteful

Repeats 99 percent of the same functionality

19

OO Development:

Develop classes that handle the different parts of a GENERIC phone communication process

(identify who to call, place a call, engage in conversation, end the call)

20

OO Development:

Set up 1 general use phone line that can handle multiple INSTANCES of phone calls to anyone who has a phone

Creates useful and extensible components

21

OO Development:

Reuses a generic communication protocol and instantiates it with a STATE based on the person you wish to talk to (phone number, etc)

22

TPS: PERSON

Think of a generic “person” blueprint and answer the following questions:

23

What ATTRIBUTES (properties) apply to the Person Blueprint ?

24

What ATTRIBUTES (properties) apply to the Person Blueprint ?

HairVoiceSizeSkin ToneGenderRaceSSNAGE

25

What BEHAVIORS (methods) apply to the Person Blueprint ?

26

What BEHAVIORS (methods) apply to the Person Blueprint ?

Change Hair ColorChange SizeChange Gender

27

What if we disallow or encapsulate the ability for ANY user of the Person Blueprint from altering hair color ?

28

How can we use this blueprint to create other types of “Persons” ?

Teacher Person

Policeman Person

Male Person

Female Person

29

How does the use of the Generic Person Blueprint assist us in creating these “instances” of the generic Person ?

30

What about Attributes and Behaviors that are different in these instances ?

31

Answers the SAME questions for:

A Generic Car Blueprint

32

Answers the SAME questions for:

A Salary Calculation Application

33

OOP

34

We will use the LOAN class analogy

There can be many types of loans: car mortgage student

35

OOP in a Nutshell:

A program models a world of interacting objects

Objects create other objects and “send messages” to each other (in Java, call each other’s methods)

Each object belongs to a class; a class defines properties of its objects

A class implements an ADT; the data type of an object is its class

Programmers write classes (and reuse existing classes)

36

Abstraction

... relevant to the given project (with an eye to future reuse in similar projects).

Abstraction means ignoring irrelevant features, properties, or functions and emphasizing the relevant ones...

“Relevant” to what?

37

Example:

In identifying the relevant elements in building a generic blueprint for handling various loans, you can ignore adding functionality that calculates the square of all natural numbers

38

Encapsulation

Encapsulation means that all data members (fields) of a class are declared private. Some methods may be private, too.

The class interacts with other classes (called the clients of this class) only through the class’s constructors and public methods. Constructors and public methods of a class serve as the interface to class’s clients.

39

Encapsulation

The Hiding or Shielding of some of the properties and or behaviors of the class from users of the class

40

Encapsulation ensures that structural changes remain local

Changes in the code create software maintenance problems

Usually, the structure of a class (as defined by its fields) changes more often than the class’s constructors and methods

Encapsulation ensures that when fields change, no changes are needed in other classes (a principle known as “locality”)

41

Example:

In building the loan class, you would hide an attribute that holds the Prime Interest Rate as well as any intermediate calculation attributes

42

Example:

Encapsulation allows the class to restrict how the attributes can be modified

43

True or False? Abstraction and encapsulation are helpful for the following:

Team development ________

Reusable software ________

GUI programming ________

Easier program maintenance ________

44

Answer:





T

T

T

(True if you are working on system packages, such as Swing)

F

45

Inheritance

A class can extend another class, inheriting all its data members and methods while redefining some of them and/or adding its own.

Inheritance represents the is a relationship between data types. For example: a HomeLoan is a ;loan.

46

Inheritance

The Use of a BASE or Blueprint class that contains the common properties and behaviors to create a subset of the class

47

Example:

With our loan class, the calculation of the Interest Rate may be the same Regardless of the type of loan. So, you could design the Loan class so that...

48

Example:

… It does the calculation and all of the loan types can inherit and USE thatCalculation.

49

True or False? Inheritance is helpful for the following:





50

Answer:





F

T

???

T

51

Polymorphism

Polymorphism ensures that the appropriate method is called for an object of a specific type when the object is disguised as a more general type.

Good news: polymorphism is already supported in Java — all you have to do is use it properly.

52

Polymorphism

The Use of a base class to serve as an interface to the use or implementation of ANY Derived Classes

53

Called Dymanic Method Binding or Late Binding

You can create a generic blueprint class that performs methods commonto any class that inherits from it.

You only need to create a placeholder of the generic class and then fill it in as needed.

54

Example:

With the car loan, we create the generic Loan class.

This Class performs the common methods and holds common attribute STATE

55

Example:

We can create a placeholder of the Loan class and then fill it with the studentloan inherited version of the Loan class

And it will , by default, contain the same public methods as the Generic Loan class

56

TPS:

Take one of the examples of Person, Car or Salary Calculation to create a SUPER BLUEPRINT that maintains attributes and behaviors that ARE COMMON regardless of the TYPE of Person, Car or Type of Salary being calculated (inheritance)

57

TPS:

Using the previous example, what attributes or behaviors can be

Hidden ?

58

Other Characteristics of OO

Divide and Conquer Principle

Interface Principle

Information Hiding Principle

Generality Principle

59

Terms:

Inheritance

Encapsulation

Polymorphism

60

Terms:

Class

Super Class

Sub / Inherited / Derrived Class

61

Terms:

Interface

Abstract Class

62

Terms:

Public

Private

Protected

63

Terms:

Attributes

Methods

Extends

64

Terms:

Override

Object

65

TEST IS NEXT !!!

1 Introduction to Object Orientation (OO) & Related Terminology zIn a non-programming specific way, orient ourselves to the principles and related terminology.

Documents

file slide

data slide

piece slide

oop slide

functionality slide

displayed slide

za generic car blueprint

generic person blueprint