Factory Methods

Factory methods in PHP classes are static methods responsible for creating and returning new instances of the class. They encapsulate the object creation process, often involving additional logic such as object caching, validation, or configuration. Factory methods are commonly used to provide a centralized and controlled way of creating objects, offering flexibility and customization options. Here are some common use cases and examples of factory methods:

Object Initialization

Factory methods can be used to create and initialize objects with predefined settings, abstracting away complex instantiation logic.

class Car {
private $model;

private function __construct($model) {
$this->model = $model;
}

public static function create($model) {
// Perform any initialization logic here
return new self($model);
}
}

$car = Car::create("Toyota"); // Creates a new Car instance with the model "Toyota"

Singleton Pattern

Factory methods can enforce the singleton pattern, ensuring that only one instance of a class exists throughout the application.

class Singleton {
private static $instance;

private function __construct() {
// Private constructor to prevent direct instantiation
}

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

$singletonInstance = Singleton::getInstance(); // Returns the singleton instance

Object Pooling

Factory methods can manage a pool of reusable object instances, improving performance by avoiding the overhead of object creation and destruction.

class ConnectionPool {
private static $connections = [];

public static function getConnection() {
if (empty(self::$connections)) {
// Create a new connection if the pool is empty
return new Connection();
} else {
// Return a connection from the pool
return array_pop(self::$connections);
}
}

public static function releaseConnection($connection) {
// Release the connection back to the pool
self::$connections[] = $connection;
}
}

$connection1 = ConnectionPool::getConnection(); // Gets a connection from the pool
// Use the connection...
ConnectionPool::releaseConnection($connection1); // Releases the connection back to the pool

Factory methods provide a flexible and controlled way of creating objects, allowing for customization and optimization of the object creation process. They are particularly useful in scenarios where object creation involves complex logic or needs to be centralized for consistency and maintainability.