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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

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]

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

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

Coupling

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

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 ?

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 ?

Coupling Component A Component B

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

Reduce coupling

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

cohesion

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

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

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

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

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

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

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

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

Reduce coupling Increase cohesion

Use these two concepts to analyze/justify design decisions.

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

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’

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)

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

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

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