There is an I in SOLID

Presentation focuses on the "interface seggregation" principle of the SOLID patterns

Transcript

1. THERE IS AN I IN SOLID
2. Waddis SOLID? Efkes over de I Voorbeeldjes Nog bitje meer over de I
3. Waddis SOLID? Efkes over de I Voorbeeldjes Nog bitje meer over de I
4. WADDIS SOLID? Acroniem
5. ACRONIEM? “Een letterwoord” “Woord gevormd door de eerste letters van andere woorden”
6. TAFKAP “The Artist Formerly Known As Prince”
7. LOL “Laughing Out Loud”
8. RTFM “Read The Fucking Manual”
9. YAGNI “You Ain't Gonna Need It”
10. DRY “Don't Repeat Yourself”
11. S Single Responsability Principle O Open/Closed Principle L Liskov Substitution Principle I Interface Segregation Principle D Dependency Inversion Principle
12. SOLID - BETEKENIS? 5 design principes Uncle Bob Martin Doel Code flexibeler, begrijpbaarder, onderhoudbaar(der..)
13. THROWBACK
14. THROWBACK
15. Waddis SOLID? Efkes over de I Voorbeeldjes Nog bitje meer over de I
16. INTERFACE SEGREGATION PRINCIPLE
17. INTERFACE
18. “Definitie van [public] methods die objecten moeten implementeren”
19. “Afspraak / Contract dat toelaat om 2 objecten met elkaar te laten communiceren”
20. “Creëert een verwachting waaraan moet voldaan worden”
21. SEGREGATION “SCHEIDING”
22. INTERFACE SEGREGATION
23. “No object should be forced to depend on methods it doesn't use”
24. “Opsplitsen van [grote] interfaces in kleinere, meer specifieke”
25. Herbruikbaarheid++ Specifiekere dependencies
26. Waddis SOLID? Efkes over de I Voorbeeldjes Nog bitje meer over de I
27. SETUP - BLOGPOST CLASS class BlogPost implements BlogPostInterface { public function getTitle() { /* ... */ } public function getContent() { /* ... */ } public function getAuthor() { /* ... */ } public function getSlug() { /* ... */ } }
28. SETUP - BLOGPOST INTERFACE interface BlogPostInterface { public function getTitle(); public function getContent(); public function getAuthor(); public function getSlug(); }
29. SETUP - USAGE $blog = new BlogPost($title, $content, $author); $blog->setSlug( $slugifier->createSlug($blog) ); /* ... */
30. SETUP - SLUGIFIER class Slugifier { /* ... */ public function createSlug(BlogPostInterface $blog) { $content = $blog->getSlugableContent(); /* ... do some magic ... */ return $slug; } /* ... */ }
31. UITBREIDING - BLOGPOSTINTERFACE interface BlogPostInterface { public function getTitle(); public function getContent(); public function getAuthor(); public function getSlug(); public function getSlugableContent(); }
32. UITBREIDING - AUTHOR CLASS class Author implements AuthorInterface { public function getFirstname() { /* ... */ } public function getLastname() { /* ... */ } public function getFullname() { /* ... */ } public function getSlug() { /* ... */ } public function getSlugableContent() { /* ... */ } }
33. UITBREIDING - AUTHOR INTERFACE interface AuthorInterface { public function getFirstname(); public function getLastname(); public function getFullname(); public function getSlug(); public function getSlugableContent(); }
34. SLUGIFIER - PROBLEEM! class Slugifier { /* ... */ public function createSlug(BlogPostInterface $blog) { $content = $blog->getSlugableContent(); /* ... do some magic ... */ return $slug; } /* ... */ }
35. SLUGIFIER - PROBLEEM! (PART 2) class Slugifier { /* ... */ public function createSlug($item) { $content = $item->getSlugableContent(); /* ... do some magic ... */ return $slug; } /* ... */ }
37. THEORETISCH... $item = Weather(); $slug = $slugifier->createSlug($weather); /* ... */
38. OPLOSSING: INTERFACE SEGREGATION
39. SUGGABLE - INTERFACE interface Slugable { public function getSlugableContent(); public function getSlug(); }
40. SLUGABLE - SLUGIFIER class Slugifier { /* ... */ public function createSlug(Slugable $item) { $content = $item->getSlugableContent(); /* ... do some magic ... */ return $slug; } /* ... */ }
41. OPLOSSING - BLOGPOST class BlogPost implements BlogPostInterface, Slugable { public function getTitle() { /* ... */ } public function getContent() { /* ... */ } public function getAuthor() { /* ... */ } public function getSlug() { /* ... */ } public function getSlugableContent() { /* ... */ } }
42. OPLOSSING - BLOGPOST INTERFACE interface BlogPostInterface { public function getTitle(); public function getContent(); public function getAuthor(); }
43. DONE!
44. NOT
45. UITBREIDING - URL'S // /2017/09/this-is-my-title $blogUrl = $urlGenerator->generateBlogUrl($blog); // /auhtor/tom-van-herreweghe $authorUrl = $urlGenerator->generateAuthorUrl($author);
46. UITBREIDING - URL'S // /2017/09/{slug} $blogUrl = $urlGenerator->generateBlogUrl($blog); // /auhtor/{slug} $authorUrl = $urlGenerator->generateAuthorUrl($author);
47. UITBREIDING - URLGENERATOR class UrlGenerator { public function generateBlogUrl(??? $item) { /* ... do some magic ... */ } }
48. PROBLEEM! Welke Visual Debt constraint toevoegen? public function generateBlogUrl(BlogPostInterface $item) public function generateBlogUrl(Slugable $item)
49. PROBLEEM! Ofwel geen zekerheid over slug-functionaliteit Ofwel geen zekerheid over Blog-item
50. OORZAAK class BlogPost implements BlogPostInterface, Slugable { public function getTitle() { /* ... */ } public function getContent() { /* ... */ } public function getAuthor() { /* ... */ } public function getSlug() { /* ... */ } public function getSlugableContent() { /* ... */ } }
51. OPLOSSING??? Komt sebiet!
52. Waddis SOLID? Efkes over de I Voorbeeldjes Nog bitje meer over de I
53. INHERITANCE Overerving
54. OBJECT CONTEXT class Circle extends Shape { /* ... */ }
55. QUIZ - KAN DIT? class Circle extends Shape, Oval { /* ... */ }
56. MULTIPLE INHERITANCE Kan niet in PHP
57. QUIZ - KAN DIT? interface Circle extends Shape { /* ... */ }
58. QUIZ - KAN DIT? interface Circle extends Shape, Oval { /* ... */ }
59. MULTIPLE INHERITANCE Kan niet in PHP in object context Kan wel in PHP: Multiple Interface Inheritance
60. class BlogPost implements BlogPostInterface { /* ... */ } interface BlogPostInterface extends Slugable { /* ... */ }
61. class UrlGenerator { public function generateBlogUrl(BlogPostInterface $item) { /* ... do some magic ... */ } }
63. PROBLEEM? NOPE!
64. INTERFACE SEGREGATION PRINCIPLE Opsplitsen interfaces in meer specifiekere Dependen op specifiekste interface Meerdere interfaces implementeren = een oplossing Multiple interface inheritance = betere oplossing
65. VRAGEN?
66. HTTPS://JOIND.IN/TALK/22707