Covers some of the Design patterns and some common ways to re-factor code. Also, how to make things in much better way, which writing your code.

1. <?php
Design Patterns
In PHP
Nishant Shrivastava
@n1shant

2. •It is a solution to a problem.
•Got a problem, chances are another DEV already has
solved it.
What is Design Pattern?

3. Why...?
●
Improve Readability
●
Improve Maintainability
●
Gain better understanding of code

4. Understanding Patterns..

5. Let me rephrase it!
Understanding Problem
Patterns...

6. Understanding Patterns...
●
Problem Patterns
●
Architectural patterns
●
Smell in Code

7. Solutions...
Refactoring
CONTEXT
PROBLEM
SOLUTION

8. D.R.Y
Do not repeat Yourself!

9. K.I.S.S
Keep.It.Simple.&.Stupid

10. Y.A.G.N.I
You ain't gonna need it!

11. Patterns...
●
Factory
●
Singleton
●
Delegate
●
Decorator
●
Strategy
●
Observer
●
Adaptor
●
State
●
Iterator
●
Front Controller
●
MVC
●
Active Record

12. Factory Pattern
●
Creates Objects without having to instantiate the classes
directly.
●
Factories creates Objects.
●
When...
●
Keep DRY when complex object creation
needs to be re-usable.
●
Encapsulate several Object creation in one.

13. Example : Factory
Class Factory {
public function create() {
return new Thing();
}
}
Class Thing {
public function doSomething() {
echo “Hello PHP'ers!”;
}
}
$factory = new Factory();
$thingObj =
$factory->create();
$thing->doSomething();

14. Singleton Pattern
●
Creates Objects without direct instantiation.
●
Does not allow more than one instance of self
●
Ensure only one instance of an obejct at any given time.
●
When...
●
Require only one instance of an class.
●
Need only one connection to a server.

15. Example : Singleton
Class SomeSingleton {
public static $instance;
private function __construct(){}
private function __clone(){}
public static function getInstance(){
If(!self::$instance instanceof self) {
self::$instance = new self();
}
Return self::$instance;
}
}
----------------------------------------------------------------------------------------
$someStaticInstance = SomeSingleton::getInstance();
$someInstance = new SomeSingleton();

16. Decorator Pattern
●
Decorator adds functionality to an object without changing
the Object's behavior.
●
When...
●
Add features or methods to an object, that are not
part of the Core logic.
●
Need extended functionality for specific use cases.

17. Example : Decorator
class User{
Public $firstName = '';
Public $lastName = '';
}
Class UserDecorator{
Private $user;
Public function __construct(User $user){
$this->user = $user;
}
Public function getFullName() {
Return “{$this->user->firstName} {$this->user->lastName}”;
}
}

18. Example : Decorator...
$user = new User();
$user->firstName = 'Chuck';
$user->firstName = 'Norris';
$decoratedUser = new UserDecorator($user);
echo $decoratedUser->getFullName();
// 'Chuck Norris'

19. Observer Pattern
●
Objects(Subject) register other objects (Observer) that
react to state changes of their subject.
●
In simple words, Observer looks for changes and
do something
l
When...
●
State Changes of an Object affect other objects or datasets
●
Event Handling
●
Data persistence
●
Logging

20. Example : Observer

21. ?>

22. Thank You!
Nishant Shrivastava
@n1shant