OOP Concept
OOP
Encapsulate business logic into objects which have properties and behaviours
objects are instance of classes blueprint for creating object
Encapsulation
- Concept of bundling the attributes and methods into the object
- Restrict the direct access to some object's component
- Access Modified
- Need Getter and Setter
Inheritance
- to inherit the properties and behaviours of another class
- extends
Polymorphism
- object can have multiple forms achieved by method overriding and method overloading
method overriding: allow subclass to provide different implementation of a method that is already defined in. its superclass
method overloading: allow multiple methods with the same name to be defined in a clas with different parameters
- When create service for different region
- BaseServiceClass
- HKServiceClass
- SGServiceClass
Abstraction
- hiding implementation details
- Interface: methods without implementation
Abstract class cannot be instantiated
Abstract Class vs Interface
- Class can extend >1 abstract class and implements multiple interfaces
- Abstract Class: can define both abstract or non-abstract method(have implementation)
- default:
protected
- default:
- Interface: default
public abstract
| Objective | |
|---|---|
| Interface | Define specification, "behavior" and "capabilities" |
| Abstract Class | For reuse of code, provide common implementation and basic function |