What are the potential pitfalls of using the Singleton pattern in PHP for managing class instances?

One potential pitfall of using the Singleton pattern in PHP for managing class instances is that it can lead to tightly coupled code, making it difficult to test and maintain. To solve this issue, you can use dependency injection to pass instances of the Singleton class where they are needed instead of directly accessing them. 

class Singleton {
    private static $instance;

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

class SomeClass {
    private $singletonInstance;

    public function __construct(Singleton $singletonInstance) {
        $this->singletonInstance = $singletonInstance;
    }
}

$singleton = Singleton::getInstance();
$someClass = new SomeClass($singleton);

Keywords

Singleton pattern PHP class instances design pattern object-oriented programming

Related Questions