An Introduction... ...to Object­Oriented Programming, Design Patterns, and Test­Driven Development By Jack Lenox ( WordPress.com VIP ) 

Slides are available at: github.com/jacklenox/introduction­to­oop 

Introducing the introduction What is Object­Oriented Programming? 

"Object­oriented programming (OOP) is a programming paradigm based on the concept of "objects", which may contain data, in the form of fields, often known as attributes; and code, in the form of procedures, often known as methods." Wikipedia 

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C++ Delphi Objective­C Java C# .NET Ruby 

PHP 5 (July 2006) 

WordPress Est. 2003 

So, what is not OOP? 

"Normal" PHP tends to come under the banner of Procedural Programming 

Procedural Programming Linear Written in the order it's executed Not necessarily modular 

Procedural Form Submission < ? p h p i f ( i s s e t ( $ _ P O S T [ ' n a m e ' ] ) ) { $ n a m e = s a n i t i z e _ t e x t _ f i e l d ( $ _ P O S T [ ' n a m e ' ] ) ; i f ( s t r l e n ( $ n a m e ) < 6 ) { e c h o ' N a m e n o t l o n g e n o u g h ' ; e x i t ; } } ? > / / F o r m i n p u t e t c . 

Object­Oriented Programming Non­linear Series of self­contained objects that can work together Modular by design 

Benefits Reduced possibility of naming clashes Modularity Reusability 

Why and when to OOP? 

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Car Attributes: Colour: Yellow Doors: 2 Luggage rack: true Methods: Accelerate Brake Steer 

Blog post Attributes: Title: My awesome blog post! Date: 2016­09­06 Sticky: false Methods: Update Publish Delete 

How to OOP? 

Language Classes Attributes Methods p r i v a t e , p r o t e c t e d , p u b l i c 

Class c l a s s C a r { / / C l a s s b o d y } 

A class is a blueprint for the objects that we want to produce 

Attributes c l a s s C a r { p u b l i c $ c o l o r ; p u b l i c $ d o o r s ; p u b l i c $ l u g g a g e _ r a c k ; } 

Methods c l a s s C a r { f u n c t i o n a c c e l e r a t e ( ) { e c h o ' T y r e s q u e a l ! ' ; } f u n c t i o n b r a k e ( ) { e c h o ' S c r e e c h ' ; } f u n c t i o n s t e e r ( $ d e g r e e ) { e c h o " S t e e r b y $ d e g r e e d e g r e e s " ; } } 

Car Factory c l a s s C a r { p u b l i c $ c o l o r = ' w h i t e ' ; p u b l i c $ d o o r s = 2 ; p u b l i c $ l u g g a g e _ r a c k = f a l s e ; f u n c t i o n a c c e l e r a t e ( ) { e c h o ' T y r e s q u e a l ! ' ; } f u n c t i o n b r a k e ( ) { e c h o ' S c r e e c h ' ; } f u n c t i o n s t e e r ( $ d e g r e e ) { e c h o " S t e e r b y $ d e g r e e d e g r e e s " ; } } 

Build a Car $ n e w _ c a r = n e w C a r ( ) ; 

Build a Yellow Car with Two Doors $ y e l l o w _ c a r = n e w C a r ( ) ; $ y e l l o w _ c a r ­ > c o l o r = " y e l l o w " ; $ y e l l o w _ c a r ­ > d o o r s = 4 ; 

Could Do Better? 

Introducing _ _ c o n s t r u c t c l a s s C a r { p u b l i c $ c o l o r ; p u b l i c $ d o o r s ; p u b l i c $ l u g g a g e _ r a c k ; f u n c t i o n _ _ c o n s t r u c t ( $ c o l o r , $ d o o r s , $ l u g g a g e _ r a c k ) { $ t h i s ­ > c o l o r = $ c o l o r ; $ t h i s ­ > d o o r s = $ d o o r s ; $ t h i s ­ > l u g g a g e _ r a c k = $ l u g g a g e _ r a c k ; } / / M e t h o d s g o h e r e } 

Build a Purple Car with Four Doors and a Luggage Rack $ p u r p l e _ c a r = n e w C a r ( ' p u r p l e ' , 4 , t r u e ) ; 

Documentation Say hello to phpDocumentor 

Documenting Classes / * * * D e f i n e s c a r f a c t o r y . * T h e c a r c l a s s p r o d u c e s c a r s * * @ p a c k a g e c a r * @ a u t h o r J a c k L e n o x * @ c o p y r i g h t 2 0 1 6 A u t o m a t t i c I n c . * / c l a s s C a r { / / C l a s s b o d y } 

Documenting Properties c l a s s C a r { / * * * T h e c a r c o l o r . * U s e d b y t h e m a n u f a c t u r i n g p r o c e s s * @ v a r s t r i n g * / p u b l i c $ c o l o r ; / * * * T h e n u m b e r o f d o o r s . * A l s o u s e d b y t h e m a n u f a c t u r i n g p r o c e s s * @ v a r i n t e g e r * / p u b l i c $ d o o r s ; / * * * W h e t h e r o r n o t t h e c a r h a s a l u g g a g e r u c k . * Y o u ' v e g u e s s e d i t , a l s o f o r m a n u f a c t u r i n g * @ v a r b o o l * / p u b l i c $ l u g g a g e _ r a c k ; / / . . . 

Documenting Methods / / . . . / * * * A c c e l e r a t e t o m o v e t h e c a r f o r w a r d s . * A c c e l e r a t i o n i s c u r r e n t l y n o t v a r i a b l e s o t h i s * m e t h o d w i l l r e t u r n a s q u e a l f r o m t h e t y r e s a s * t h e w h e e l s s p i n . * @ r e t u r n s t r i n g * / f u n c t i o n a c c e l e r a t e ( ) { r e t u r n ' T y r e s q u e a l ! ' ; } / / . . . 

Unit Testing and Test­Driven Development Say hello to PHPUnit 

A Basic Test u s e P H P U n i t \ F r a m e w o r k \ T e s t C a s e ; r e q u i r e _ o n c e ( ' c l a s s ­ c a r . p h p ' ) ; c l a s s C a r T e s t e x t e n d s T e s t C a s e { p r i v a t e $ c a r ; p u b l i c f u n c t i o n s e t U p ( ) { $ t h i s ­ > c a r = n e w C a r ( ' y e l l o w ' , 4 , t r u e ) ; } p u b l i c f u n c t i o n t e a r D o w n ( ) { } p u b l i c f u n c t i o n t e s t G e t C a r ( ) { $ t h i s ­ > a s s e r t E q u a l s ( $ t h i s ­ > c a r ­ > c o l o r , ' y e l l o w ' ) ; $ t h i s ­ > a s s e r t E q u a l s ( $ t h i s ­ > c a r ­ > d o o r s , 4 ) ; $ t h i s ­ > a s s e r t T r u e ( $ t h i s ­ > c a r ­ > l u g g a g e _ r a c k ) ; } } 

Run the Test $ p h p u n i t ­ ­ v e r b o s e t e s t s P H P U n i t 5 . 5 . 4 b y S e b a s t i a n B e r g m a n n a n d c o n t r i b u t o r s . R u n t i m e : P H P 7 . 0 . 8 ­ 0 u b u n t u 0 . 1 6 . 0 4 . 2 . 1 / 1 ( 1 0 0 % ) T i m e : 1 0 5 m s , M e m o r y : 8 . 0 0 M B O K ( 1 t e s t , 3 a s s e r t i o n s ) 

Design Patterns 

Singletons and Inheritance 

OOP and WP in Practice Widgets API The Walker Class WP_Rewrite 

Widgets API c l a s s M y _ W i d g e t e x t e n d s W P _ W i d g e t { / * * * S e t s u p t h e w i d g e t s n a m e e t c * / p u b l i c f u n c t i o n _ _ c o n s t r u c t ( ) { $ w i d g e t _ o p s = a r r a y ( ' c l a s s n a m e ' = > ' m y _ w i d g e t ' , ' d e s c r i p t i o n ' = > ' M y W i d g e t i s a w e s o m e ' , ) ; p a r e n t : : _ _ c o n s t r u c t ( ' m y _ w i d g e t ' , ' M y W i d g e t ' , $ w i d g e t _ o p s ) ; } / / / C o n t i n u e s . . . 

/ * * * O u t p u t s t h e c o n t e n t o f t h e w i d g e t * * @ p a r a m a r r a y $ a r g s * @ p a r a m a r r a y $ i n s t a n c e * / p u b l i c f u n c t i o n w i d g e t ( $ a r g s , $ i n s t a n c e ) { / / o u t p u t s t h e c o n t e n t o f t h e w i d g e t } / * * * O u t p u t s t h e o p t i o n s f o r m o n a d m i n * * @ p a r a m a r r a y $ i n s t a n c e T h e w i d g e t o p t i o n s * / p u b l i c f u n c t i o n f o r m ( $ i n s t a n c e ) { / / o u t p u t s t h e o p t i o n s f o r m o n a d m i n } 

/ * * * P r o c e s s i n g w i d g e t o p t i o n s o n s a v e * * @ p a r a m a r r a y $ n e w _ i n s t a n c e T h e n e w * o p t i o n s * @ p a r a m a r r a y $ o l d _ i n s t a n c e T h e p r e v i o u s * o p t i o n s * / p u b l i c f u n c t i o n u p d a t e ( $ n e w _ i n s t a n c e , $ o l d _ i n s t a n c e ) { / / p r o c e s s e s w i d g e t o p t i o n s t o b e s a v e d } } 

The Walker Class ( code.tutsplus.com/tutorials/understanding­ the­walker­class­­wp­25401 ) 

Conclusion 

WPPB ( wppb.me ) Tom McFarlin's Tuts+ Series ( tommcfarlin.com/object­oriented­ programming­in­wordpress/ ) 

When not to OOP? 

Trouser­Oriented Clothing, Noun­ Oriented Language etc. 

Functional Programming? Execution in the Kingdom of Nouns ( steve­yegge.blogspot.sg/2006/03/execution­in­ kingdom­of­nouns.html ) 

OOP is not necessarily the "right way" 

But it's much better than this! 

Thank you github.com/jacklenox/introduction­to­oop automattic.com/work­with­us/