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Object Oriented Paradigm
Programming Paradigms
En Mohd Norafizal A.Aziz
Contents
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Definition of object oriented
Basic concepts
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Objects
Classes
Messages
Encapsulation
Inheritances
Abstract classes and Interfaces
Polymorphism
Sample of code
Conclusion
Blind man and Elephant
What is Object Oriented
Allows programmers to write computer
programs by representing elements of a
real-world problem in the form of so-called
objects.
 Objects are represent both: behaviors of
real world objects as well as their
characteristics.
 All work in this concepts are using
messages.
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Advantages of Object Oriented
OOP provides a clear modular structure
for programs.
 OOP is easy to maintain.
 OOP provides a good framework for code
libraries.
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Objects
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Objects are the physical and conceptual things
we find in the universe around us.
Hardware, software, documents, human beings,
and even concepts are all examples of objects.
Objects are thought of as having state. The
state of an object is the condition of the object,
or a set of circumstances describing the object.
However, it is possible for some objects to
change their own state. If an object is capable of
spontaneously changing its own state, we refer
to it as an “object with life”.
Objects is …
An objects has a state, exhibits
some well defined behavior and
has a unique identity.
Generally, OOP approach may be seen as
manipulation with multiple objects.
 Programmers can :
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Create new objects
 Send message to existing objects
 Collect responses in a form of objects to
which other messages may be sent.
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Sample of coding
BankAccount myAccount = new BankAccount ();
String myname = new String (‘Fizal’);
Employee meAsemployee = new Employee
(myname, myAccount);
Consists of three fundamentals part :
Variable declaration – Instantiation -- Initialization
Classes
A class represent a set of objects that
share common structure and a common
behavior.
 Example: CAR
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State ( gear, speed, etc)
 Behavior (change gear, accelerate etc)
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Classes is …
Is a prototype that defines
variables and methods that are
common to all objects of the
same kind.
Sample of coding
Public class Employee
{
// variables
private String Name;
private BankAccount B_Account;
// methods
public String salary (int sum)
{
// method body
}
}
Public class Name
{
private String nama;
public Name () // default constructor
{}
public Name (String nama)
{ this.nama = nama; }
String getNama()
{ return nama; }
void setNama(String Nama)
{ this.nama = nama;
}
public String toString()
{ return nama
}
}
class
{ int
int
int
Bicycle
cadence = 0;
speed = 0;
gear = 1;
void changeCadence(int newValue)
{ cadence = newValue; }
void changeGear(int newValue)
{ gear = newValue; }
void speedUp(int increment)
{ speed = speed + increment; }
void applyBrakes(int decrement)
{ speed = speed - decrement; }
void printStates()
{ System.out.println("cadence:"+cadence+"
speed:"+speed+" gear:"+gear); }
}
Import java.io;
Public class hello
{
public static void main (String args [])
{
System.out.pritnln(“Hello…World”);
}
}
Messages
Single objects are not very useful. Instead,
an object usually appears as just one
object of an object-oriented program that
contains many objects.
 In such program all works is done by
interaction between these objects.
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Sample of messages
Employee meAsemployee = new Employee(myname,
myAccount);
meAsemployee.salary(1000);
References
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Java Tutorials:
http://java.sun.com/docs/books/tutorial/java/concepts/
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Wikipedia:
http://en.wikipedia.org/wiki/Object-oriented_programming
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Keywords:
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object oriented concepts in java with examples.
Object Oriented concepts