KUFAHAMU PHP DESIGN PATTERNS KWA PROJECTS

Design Patterns ni solutions reusable kwa common problems katika software design:

Improve code organization

Increase reusability

Facilitate maintenance

Standardize best practices

Goal: Write clean, maintainable, and scalable code.

⚙️ 2. Common PHP Design Patterns
a) Singleton Pattern

Ensure only one instance of a class exists:

<?php
class Database {
private static $instance = null;
private $pdo;

private function __construct(){
$this->pdo = new PDO("mysql:host=localhost;dbname=mvc_db;charset=utf8mb4","root","");
$this->pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}

public static function getInstance(){
if(self::$instance === null){
self::$instance = new Database();
}
return self::$instance;
}

public function getConnection(){
return $this->pdo;
}
}

// Usage
$db = Database::getInstance()->getConnection();

b) Factory Pattern

Create objects dynamically without specifying exact class:

<?php
interface Shape {
public function draw();
}

class Circle implements Shape {
public function draw(){ echo "Drawing Circle"; }
}

class Square implements Shape {
public function draw(){ echo "Drawing Square"; }
}

class ShapeFactory {
public static function create($type){
if($type === 'circle') return new Circle();
if($type === 'square') return new Square();
}
}

// Usage
$shape = ShapeFactory::create('circle');
$shape->draw(); // Output: Drawing Circle

c) Observer Pattern

Notify multiple objects of a state change:

<?php
class Event {
private $observers = [];

public function attach($observer){ $this->observers[] = $observer; }
public function notify(){
foreach($this->observers as $observer){
$observer->update();
}
}
}

class UserObserver {
public function update(){ echo "User updated!\n"; }
}

$event = new Event();
$event->attach(new UserObserver());
$event->notify();

d) MVC Pattern (Architectural Pattern)

Separate Model, View, Controller for maintainable PHP applications:

project_root/
│
├── app/
│ ├── controllers/
│ ├── models/
│ └── views/
├── core/
├── public/
└── config/


Model: handles database

View: handles presentation

Controller: handles business logic

🔑 3. Best Practices

Understand problem first – pick the right pattern for the situation

Keep patterns consistent across project

Combine patterns when needed – e.g., Singleton DB + MVC + Factory

Document your design choices for team collaboration

Use namespaces & autoloading – organize patterns cleanly

✅ 4. Hitimisho

PHP design patterns improve code quality, maintainability, and scalability

Essential for medium to large projects

Combine with MVC, namespaces, Composer, and secure coding practices for robust applications

🔗 Tembelea:

👉 https://www.faulink.com/

Kwa mafunzo zaidi ya PHP, design patterns, na best practices za professional development.