Code Quality Series- 1 Understanding OOPs concepts

Slides of PHP Reboot meetup on 'Understanding OOPs concepts' under 'Code Quality' meetup series.

Code discussed during meetup can be found at https://github.com/phpreboot/OOPsMeetupCode

Meet up video is also uploaded to PHPReboot youtube channel (Check slide 3).

Transcript

1. PHPReboot.com KapilSharma.info Code Quality Series 1 1. Understanding OOPs concepts
2. PHPReboot.com KapilSharma.info About me • Kapil Sharma • VP Technology at DJ Alexander • Working in web application development since 13+ years. • Twitter: @kapilsharmainfo • Facebook: /kapilsharmainfo • Linked in: kapilsharmainfo • Website: kapilsharma.info • Slides: speakerdeck.com/kapilsharma 2
3. PHPReboot.com KapilSharma.info About PHP Reboot • Developers’ community in Pune, India. • Conducts regular meet ups • meetup.com/phpreboot • phpreboot.com • Twitter: @phpreboot • Facebook: /PHReboot • Slack: phpreboot.signup.team • Youtube: www.youtube.com/channel/ UCbLir8nYAFJ5YpcbjEFzjVw 3 Please subscribe, so that we can get custom Channel URL like youtube.com/phpreboot (Need 100 subscribers to get custom URL) Sponsored by JetBrains (IDE License) DJ Alexander (Space and snacks) Ansh Systems (Space and snacks)
4. PHPReboot.com KapilSharma.info Why we are here? 4 1. Understanding OOPs concepts Code Quality Series
5. PHPReboot.com KapilSharma.info What is quality code? • Easy to read. 5 • Easy to extend.
6. PHPReboot.com KapilSharma.info Easy to read 6
7. PHPReboot.com KapilSharma.info – Martin Fowler “Any fool can write code that Computer can understand. Good programmers write code that Humans can understand.”
8. PHPReboot.com KapilSharma.info – Edsger W. Dijkstra “Simplicity is prerequisite for reliability” “Simple is better”
9. PHPReboot.com KapilSharma.info Easy to extend 9 O of SOLID Open Close Principle Our code must be Open for Extension But Close for Modification
10. PHPReboot.com KapilSharma.info How to achieve? • Readable: Less time to understand what code is doing. • Simple - KISS • Single responsibility (SOLID) • Small class/methods • Consistent standards • Commonly agreed Naming convention 10 Easy to read Easy to extend • Extendability: Easy to meet new requirements without breaking existing code • DRY • Open-Close (SOLID) • Small class/method • Moduler • Continuous refactoring (consider TDD)
11. PHPReboot.com KapilSharma.info Code Quality Series 11 1. Understanding OOPs concepts
12. PHPReboot.com KapilSharma.info – Kapil Sharma “OOPS Follow it or feel it”
13. PHPReboot.com KapilSharma.info Object Oriented Programming (OOPs) 13 Class and objects
14. PHPReboot.com KapilSharma.info Object Oriented Programming (OOPs) • Encapsulation • Abstraction • Inheritance • Polymorphism 14 Class and objects • Class • Class • Interface/Abstract class/ parent/child class • Overloading/Overriding How the hell they are going to help in code quality?
15. PHPReboot.com KapilSharma.info Object Oriented Programming (OOPs) • Encapsulation • Abstraction • Inheritance • Polymorphism 15 Class and objects • Class • Class • Interface/Abstract class/ parent/child class • Overloading/Overriding How the hell they are going to help in code quality?
16. PHPReboot.com KapilSharma.info Interface / Abstract class • Interface - Declare methods • Abstract - Declare & Define methods 16 Coding for an interface Dependency Injection
17. PHPReboot.com KapilSharma.info Coding for an interface 17 Slides from Laravel meetup: https://speakerdeck.com/kapilsharma/laravel
18. PHPReboot.com KapilSharma.info Coding for an interface 18 Slides from Laravel meetup: https://speakerdeck.com/kapilsharma/laravel
19. PHPReboot.com KapilSharma.info Coding for an interface 19 Slides from Laravel meetup: https://speakerdeck.com/kapilsharma/laravel
20. PHPReboot.com KapilSharma.info Coding for an interface 20 Slides from Laravel meetup: https://speakerdeck.com/kapilsharma/laravel
21. PHPReboot.com KapilSharma.info Coding for an interface 21 Slides from Laravel meetup: https://speakerdeck.com/kapilsharma/laravel
22. PHPReboot.com KapilSharma.info Coding for an interface 22 Slides from Laravel meetup: https://speakerdeck.com/kapilsharma/laravel
23. PHPReboot.com KapilSharma.info Code example - Problem statement • We want to build a calculator that receives two numbers and does an operation. 23 • We do not know which kind of operations we want to do yet, we will get them in the future (future business requirements) and this calculator may have really complex operations. • Currently planned operations are: • Sum • VAT (amount, VAT rate) • Different team will be adding parallel operations to this calculator so it must be easily extendable and using dependency injection.
24. PHPReboot.com KapilSharma.info Solution 24 Img source: https://pixabay.com/en/businesswoman-solution-conflict-617128/ https:// github.com/ phpreboot/ OOPsMeetupCode
25. PHPReboot.com KapilSharma.info Solution • Since we do not know future operations: 25 • We must define solution using Open-Close principle • Open for extension (Can add new operation) • Close for modification (We must not edit existing operation, until there is change request.
26. PHPReboot.com KapilSharma.info Contract (Interface) • Contract - Will guide future operations. 26
27. PHPReboot.com KapilSharma.info Defining operation • Why separate class for each operation • Help adding future requirement, without impacting current operations. • Since one operation have one class, it follows ‘Single Responsibility Model’ and KISS (Keep It Simple and Stupid) principle. 27
28. PHPReboot.com KapilSharma.info Example Operation - Addition 28
29. PHPReboot.com KapilSharma.info Getting operation instance • We have different class for different operation • Creating instance for proper operation, is separate business logic, and must reside in different class. • This is called Factory Pattern - OperationFactory 29
30. PHPReboot.com KapilSharma.info OperationFactory 30
31. PHPReboot.com KapilSharma.info Operation Command • Now main business logic, will remain unchanged. It simple get instance from factory and run execute method. • In example git repository, we used Symfony/console component to make executable console application. • Symfony/Console is easy symfony component, check its documentation for details. 31
32. PHPReboot.com KapilSharma.info Console command 32
33. PHPReboot.com KapilSharma.info Output 33 git clone https://github.com/phpreboot/OOPsMeetupCode.git composer install cd OOPsMeetupCode
34. PHPReboot.com KapilSharma.info How to achieve? • Readable: Less time to understand what code is doing. • Simple - KISS • Single responsibility (SOLID) • Small class/methods • Consistent standards • Commonly agreed Naming convention 34 Easy to read Easy to extend • Extendability: Easy to meet new requirements without breaking existing code • DRY • Open-Close (SOLID) • Small class/method • Moduler • Continuous refactoring (consider TDD)
35. PHPReboot.com KapilSharma.info Thanks! Questions? 35