1. Chapter 10 Thinking in Objects

2. Principle of OOP Inheritance Abstraction Encapsulation Polymorphism
Also know as (APIE)

3. Inheritance and Composition
A class can extend another class.
Inheritance implements the “ IS a” relationship between objects
A class can implements interface, methods members from its parent class.

4. Inheritance and Composition
Is- A and Has –A
Inheritance VS Composition
Favor Composition
Polymorphism
Interfaces

5. Is-A and Has-A relationship
Classes depend on another class
Classes are related via Is –A or Has –A relationship
Cat-> Animal = IS-A
Car->Wheel, Engine =Has -A
Train->Wheel,Engine=Has -A
Car,Truck-> Vehicle= Is-A
HAS-A=Composition (compose)
IS-A=Inheritance(subtype)
Reuse code

6. Inheritance (Is-A) Animal Cat
Animal is a base class cat class inheritances from animal
Animal
Cat

7. Inheritance Syntax Java Supports only public inheritance
A is a Superclass and B is a Subclass

8. Inheritance Syntax In order to call the constructor of
superclass(A) the keyword super is used

9. Composition (Has-A) car wheel Engine
Something is made up of other parts
Car contains wheel and engine
It is also called aggregation
car
wheel
Engine

10. Composition (Has-A):aggregation
Composition(HAS-A) simply mean use of instance variables that are references to other objects. For example: Maruti has Engine, or House has Bathroom

11. Composition (Has-A):aggregation

12. Aggregation Lab

13. Inheritance Lab
Follow the instructions provided on Lab9