This document discusses the SOLID principles of object-oriented design, beginning with an explanation of the Dependency Inversion Principle (DIP). DIP states that high-level modules should not depend on low-level modules, both should depend on abstractions. The document then explains the Open-Closed Principle (OCP), which states that software entities should be open for extension but closed for modification. Examples are given to illustrate each principle. The document aims to provide an introduction to SOLID and its benefits for maintainable object-oriented software design.

1. Week1. SOLID
Section 1.
11 1
Covenant Ko
2021. 05. 26(Wed)

2. - Name. Covenant.
- Company. 11번가
- Github 용감한친구들 Organization Founder & Maintainer. https://github.com/brave-people
- Github. https://github.com/KoEonYack
- Tech Blog. https://covenant.tistory.com/ (누적 방문 41만)

3. EJB Spring

4. Spring

5. Spring
5 (SOLID)
? ?
SOLID vs

6. Week1. SOLID
Section 1.

7. Week1. SOLID
Section 1.
SOLID (go !!)

8. 1. DIP(Dependency Inversion Principle)
One might question why I use the word “inversion”. Frankly, it is because
more traditional software development methods, such as Structured
Analysis and Design, tend to create software structures in which high
level modules depend upon low level modules, and in which abstractions
depend upon details. Indeed one of the goals of these methods is to
define the subprogram hierarchy that describes how the high level
modules make calls to the low level modules. ... Thus, the dependency
structure of a well designed object oriented program is “inverted” with
respect to the dependency structure that normally results from
traditional procedural methods.
Robert C Martin's

9. 1. DIP(Dependency Inversion Principle)
One might question why I use the word “inversion”. Frankly, it is because
more traditional software development methods, such as Structured
Analysis and Design, tend to create software structures in which high
level modules depend upon low level modules, and in which abstractions
depend upon details. Indeed one of the goals of these methods is to
define the subprogram hierarchy that describes how the high level
modules make calls to the low level modules. ... Thus, the dependency
structure of a well designed object oriented program is “inverted” with
respect to the dependency structure that normally results from
traditional procedural methods.
Robert C Martin's

10. 1. DIP(Dependency Inversion Principle)
1. .
2. . .

11. 1. DIP(Dependency Inversion Principle)
…

12. 1. DIP(Dependency Inversion Principle)
•
•

13. 1. DIP(Dependency Inversion Principle)
Order PaymentService
BankPaymentService
( )
ImportService

14. 1. DIP(Dependency Inversion Principle)
Order PaymentService
pay()
BankPaymentService
pay()
? ? .
( ) . ( …)
.
.
Clean Code 194p
ImportService
pay()

15. 1. DIP(Dependency Inversion Principle)
? ? .
( ) . ( …)
.
.
Clean Code 194p
…
…
.
Bus factor(lotto factor)

16. 1. DIP(Dependency Inversion Principle)
Order PaymentService
BankPaymentService
SEPERATED INTERFACE PATTERN
ImportService

17. 1. DIP(Dependency Inversion Principle)
•
• .(B2B …) ➔ ➔ ..
➔ ➔ ( …)
• ➔ ➔ ? ➔ ? ➔
➔ . !

18. 1. DIP(Dependency Inversion Principle)
Go

19. 1. DIP(Dependency Inversion Principle)
fields{RegionSvc: &mockRegionService{}} , -
. .
. Worker
,
! ( …)
. Go
. ( …)
#
# SOLID

20. Note that Dependency Injection (DI) is ONE of the possible implementations to achieve the
Dependency Inversion Principle (DIP)
1. DIP(Dependency Inversion Principle)
Stack overflow: What is meant by 'Inversion' in Dependency inversion

21. 2. OCP(Open-Closed Principle)
( ) 251p
Magic????

22. 2. OCP(Open-Closed Principle)
운전자 마티즈
창문_수동_개방()
기어_수동_조작()
운전자 소나타
창문_자동_개방()
기어_수동_조작()

23. 2. OCP(Open-Closed Principle)
운전자 자동차
창문_개방()
기어_조작()
마티즈
창문_개방()
기어_조작()
소나타
창문_개방()
기어_조작()

24. _
2. OCP(Open-Closed Principle)
• , ( ..)
• Util or hotfix
•

25. Week1. SOLID END.