Object Oriented Programming
Basic
Visibility
| Object | SubClass | SelfClass | |
|---|---|---|---|
| public | v | v | v |
| protected | x | v | v |
| private | x | x | v |
Class
- Constructor
- Field
- variable
- constant
- Method
- Regular
- depends on object
- Static
- depends on class
- Destructor
Encapsulation
don’t operate data directly, use methods by parameters and arguments:
- Getter, Accessors
- Setter, Mutator
Inherited
- IS-A
- Is a Dog an Animal?
- HAS-A
- Dog has a Height.
Polymorphism
SubClass can override SuperClass methods, and be used when it’s declared as a SuperClass object.
Abstract Class
- It’s like “theory of Forms”(Plato) in philosophy. - Dino Lai
- use the power of Polymorphism without the work.
- all the method in abstract should be abstract.
- no abstract fields.
Interface
- It’s like contract with employee and employer. - Dino Lai
- Only declares methods to be implemented.