1. Holub on Patterns
Remove extends
charsyam@naver.com

2. Why
Removes
Extends?

3. Extends is not Bad.

4. Just.
Using Concrete Class
is Bad

5. Use Interface!

6. How to Remove Extens?

10. Use Abstract Factory!

11. Using 1

12. Factory
<<interface>> EmployeeFactory
Employee
<<Employee>>+create()
Peon
<<void>>+youAreFired()

13. Using 2

14. Using 3

15. Use Abstract Factory!

16. 2 Patterns
Singleton
Abstract Factory

17. Pass Singleton Pattern
Threading Issue
Don’t Use Double-Checked Locking

18. Abstract Factory Pattern
NOT Factory Method Pattern
Factory is changable

19. Abstract Factory Pattern

21. Abstraction 1
Employee.Factory.create();

22. Abstraction 2
Employee.Factory.create();
Employee.create();

23. Java Example
HttpURLConnection
FtpURLConnection

24. 2 Patterns
Command
Strategy

25. Pass Command Pattern
Default Pattern

26. Strategy Example

27. Thank You!