Dr. Javier Gonzalez-Sanchez javiergs@calpoly.edu www.javiergs.info o ffi ce: 14 -227 CSC 305 Individual Software Design and Development Lecture 02. Clean Coding

Clean Coding • Write e ff icient code but prioritize re a d a bility a nd m a int a in a bility. • Optimize perform a nce-critic a l sections only when necess a ry. 2

Manufacturing vs. Crafting

Clean Coding Single Responsibility Principle (SRP) Do not Repeat Yourselves (DRY) Keep It Simple (KIS) Error Handling Readability (Easy to read to others) Style and Comments Dependency Injection (DI)

Style and Comments

Consistent Formatting • Follow a consistent code style a nd form a tting guidelines. https://google.github.io/styleguide/javaguide.html • Use indent a tion, whitesp a ce, a nd comments e ff ectively to enh a nce re a d a bility. 6

Meaningful Names • Use descriptive a nd un a mbiguous n a mes for v a ri a bles, functions, cl a sses, etc. • Avoid using misle a ding or cryptic n a mes. • Follow consistent n a ming conventions. 7

Commenting and Documentation • Write me a ningful comments th a t expl a in why something is done, not wh a t is done. • Keep comments up to d a te with code ch a nges. • Document public APIs a nd complex logic thoroughly. • Single Line vs Multiple Line ( a nd J a v a Doc) comments 8

Code 9 https://github.com/CSC3100/App-Paint/

Code 10 https://github.com/CSC3100/App-Paint/

DRY

Don't Repeat Yourself (DRY) • Avoid code duplic a tion by a bstr a cting common function a lity. • Use functions or cl a sses to enc a psul a te repe a ted jobs. 12

KIS

Keep It Simple (KIS) • Aim for simplicity in your design a nd implement a tion. • Avoid unnecess a ry complexity or over-engineering. 14

Code 15 https://github.com/CSC3100/App-Paint/

Code 16 https://github.com/CSC3100/App-Paint/

Single Responsibility

Single Responsibility • E a ch cl a ss or function should h a ve one, a nd only one, job. • Keep functions focused on a single t a sk. • Bre a k down your code into sm a ller, reus a ble modules or functions. • Ensure e a ch module or function h a s a cle a r, well-de f ined purpose. • 18

Example 19

Some Ideas. It is NOT a Complete List 20 MOVE EAT SHOW DETECT COLLISION MOVE/ HUNT SHOW SHOW/ CREATE SCORE HANDLING WINNER DETECTOR MOVE/ HUNT

Tic Tac Toe 21 Main Player Game

Tic Tac Toe 22 Main Player GameEngine GameBoard

Tic Tac Toe 23 Driver Player Game public class Driver { public static void main(String[] arg) { Player player = new Player(); Game game = new Game(); game.ready(); do { player.move(); game.move(); } while (!game.isOver()); game.bye(); } }

Dependency Injection

Dependency Injection • An object’s dependencies (other objects it relies on) a re provided extern a lly r a ther th a n cre a ted intern a lly by the object itself. • Constructor injection: Dependencies a re p a ssed vi a the cl a ss constructor. • Setter injection: Dependencies a re provided through setter methods. • M a ke components more a ccessible to sw a p or extend without modifying the dependent cl a ss. 25

Dependency Injection What about text-based vs. GUI?

Tic Tac Toe 27 Main Player Game View

Dependency Injection 28 public class Driver { public static void main(String[] arg) { View view = new View (); Player player = new Player(view); Game game = new Game(view); game.ready(); do { player.move(); game.move(); } while (!game.isOver()); game.bye(); } }

Dependency Injection 29 public class Driver { public static void main(String[] arg) { View view = new View (); Player player = new Player(view); Game game = new Game(view); game.ready(); do { player.move(); game.move(); } while (!game.isOver()); game.bye(); } } public class View { public void print(String s) { System.out.println(s); } } public class Game { View myView; public Game(View v) { myView = v; } public void ready() { myView.print (“Welcome!”); } // more code … }

Questions 30

Lab 01

Apply these Single Responsibility Principle (SRP) Do not Repeat Yourselves (DRY) Keep It Simple (KIS) Error Handling Readability (Easy to read to others) Style and Comments Dependency Injection (DI)

Lab 02 (Quiz)

Quiz (45 minutes - 15 questions) Let’s Test Your Java Programming

CSC 305 Individual Software Design and Development Javier Gonzalez-Sanchez, Ph.D. javiergs@calpoly.edu Winter 2025 Copyright. These slides can only be used as study material for the class CSC305 at Cal Poly. They cannot be distributed or used for another purpose.