Encapsulation
Principle of OOP
What is encapsulation?
Why it is important?
Code improvement using encapsulation
Encapsulation in Design Patern
Contents:
Inheritance
Principle of OOP
Polymorphism
Encapsulation
Abstraction
Recap
What is Inheritance ?
Without Inheritance
With Inheritance
Child class can reuse attribute and method in parent class
What is Polymorphism ?
Many Forms. The ability to take different form.
An animal at the same time can have different characteristic.
Like a cow at the same time is a sport animal, a milk animal, and is also a meat animal.
So the same animal posses different behavior in different situations. This is called polymorphism.
What is Encapsulation ?
- Reducing dependencies between objects by hiding the internal representation of an object behind specific method.
- Concept of bundling data related variables and properties with behavioral methods in one class or code unit.
Example of starting a car
The Process Flow
What User Do
Why it is important ?
- Allow use of an item through a set of simple actions. You don't need to know the internals.
- In term of code, you use item through an object method rather than through direct object attributes.
- An approach for restricting direct access to some of the data structure elements (fields, properties, methods).
Example
public class Car {
private String model;
private int year;
private double price;
Car(String model,int year,double price){
setModel(model);
setYear(year);
setPrice(price);
}
//setter
public void setModel(String model) {
this.model = model;
}
public void setYear(int year) {
this.year = year;
}
public void setPrice(double price) {
this.price = price;
}
//getter
public String getModel() {
return model;
}
public int getYear() {
return year;
}
public double getPrice() {
return price;
}
}public class Main {
public static void main(String[] args) {
Car car1 = new Car("Mustang",2021,9999.99);
car1.setModel("Corvette");
car1.setYear(2022);
car1.setPrice(5000);
System.out.println(car1.getModel());
System.out.println(car1.getYear());
System.out.println(car1.getPrice());
}
}Car Class
Main Class
Code Before and After
let baseSalary = 4000;
let overtime = 10;
let rate = 20;
function getWage(baseSalary, overtime, rate){
return baseSalary + (overtime * rate)
}let employee = {
baseSalary: 4000,
overtime: 10,
rate: 20,
getWage: function() {
return this.baseSalary + (this.overtime * this.rate)
}
};
employee.getWage();Before
After
"The best function are those with no parameters!"
Uncle Bob - Robert C Martin
Example of design patern that use encapsulation
Stratergy Patern
Encapsulation
By Syafiq bin abdul rahman
