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2. Which is the better Minesweeper design and why?
Logic
Minefield
Storage
Logic
Minefield
Storage
:Logic
m:Minefield
:Storage
:Logic
m:Minefield
:Storage
mark
mark
mark
mark
update(m)
update(m)
get info
get info

3. CS2103/T, Lecture 7, Part 1, [Oct 2, 2015]
To Tighten or Loosen:
What Makes a Good Component.
CS2103/T, Lecture 7, Part 1, [Oct 2, 2015]

4. What Makes a Good Component.
To Tighten or Loosen:
What Makes a Good Component.
Coupling
Cohesion

5. What Makes a Good Component.
To Tighten or Loosen:
What Makes a Good Component.
Coupling
Cohesion

6. Coupling

7. If I change B , will it require a change in A ? NO WAY It might
Dependency ==
Coupling
(Class/method/…)
Component A
Component B
If I change B , will it require a change in A ?
NO WAY
It might

8. If I change B , will it require a change in A ?
Coupling
Component A
Component B
If I change B , will it require a change in A ?

9. If I change B , will it require a change in A ?
Coupling
Component A
Component B
If I change B , will it require a change in A ?

10. Coupling
Component A
Component B

11. If I change B, will it require a change in A? Yes, It might
Component A
Component B
If I change B, will it require a change in A? Yes, It might
Reduce coupling

12. Reduce coupling

13. Good Component design Reduce coupling cohesion Parser Logic
Unnecessary coupling example: Chef keeps his/her cash in the cash register? Does Parser has any business being coupled to Logic?
cohesion

15. cohesion

16. Does one thing and does it all
cohesion
Does one thing and does it all
Component A
Component B
Component C

17. Does one thing and does it all
cohesion
Does one thing and does it all
Window 1
Component A
Window 2
Window 3

18. Does one thing and does it all
cohesion
Does one thing and does it all
Component A
Component B
Component C

19. Does one thing and does it all
cohesion
Does one thing and does it all
Component A
Component B
Component C

20. Does one thing and does it all
cohesion
Does one thing and does it all
Component A
Component B
Component C

21. Does one thing and does it all
cohesion
Does one thing and does it all
Component A
Component B
Component C
Increase cohesion

22. Does one thing and does it all
cohesion
Does one thing and does it all
Component A
Component B
Component C
Increase cohesion

23. Good Component design Reduce coupling Increase cohesion Parser Logic
The chef takes care of all things related to cooking  cohesion

24. Reduce coupling
Increase cohesion

25. Use these two concepts to analyze/justify design decisions.

26. Which is the better design and why?
Logic
Minefield
Storage
Logic
Minefield
Storage

27. Which is the better design and why?
Logic
Minefield
Storage
Logic
Minefield
Storage
Refer to Coupling and Cohesion when analyzing designs
How does this application of SRP change C & C?
TextUi
Formatter
Use the right terms, give a sensible explanation, including assumptions, instead of ‘b looks messy’ or ‘a is prettier’

28. Dependency Inversion Principle
High-level class coupled to low-level class
Low-level class coupled to high-level class
Logic
Minefield
Logic
Minefield
Logic
{abstract} Field
Minefield
Logic
<<interface>> Field
Minefield
Dependency Inversion Principle
High-level modules should not depend on low-level modules. Both should depend on abstractions
(should  sometimes, preferred not to)

29. Dependency Inversion Principle
High-level class coupled to low-level class
Logic
Minefield
Farmfield
Logic
<<interface>> Field
Minefield
Dependency Inversion Principle
High-level modules should not depend on low-level modules. Both should depend on abstractions

30. Open-Closed Principle
A class should be open for extensions but closed for modifications
{abstract} Timer
FixedTimer
Random Timer
Farmfield
Main
Logic
<<interface>> Field
Minefield
Chess Main
Chessboard
SinglePlayer Logic
SP Main

31. S O L I D Single Responsibility Principle Open-Closed Principle
Liskov Substitution Principle
Interface Segregation Principle
Dependency Inversion Principle