디자인 패턴을 사용하여 PHP 기능의 아키텍처와 성능을 최적화하는 방법은 무엇입니까?

class Database {
    private static $instance;

    private function __construct() {
        // 连接数据库
    }

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

        return self::$instance;
    }
}

class EventManager {
    private $subscribers = [];

    public function subscribe($subscriber) {
        $this->subscribers[] = $subscriber;
    }

    public function unsubscribe($subscriber) {
        unset($this->subscribers[$subscriber]);
    }

    public function notify($event) {
        foreach ($this->subscribers as $subscriber) {
            $subscriber->update($event);
        }
    }
}

class ShapeFactory {
    public function createShape($type) {
        switch ($type) {
            case 'square':
                return new Square();
            case 'circle':
                return new Circle();
            default:
                throw new Exception('Invalid shape type');
        }
    }
}

function multiplyArray($array, $factor) {
    foreach ($array as $key => $value) {
        $array[$key] = $value * $factor;
    }

    return $array;
}

class ArrayMultiplyObserver {
    private $array;

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

    public function update($factor) {
        foreach ($this->array as $key => $value) {
            $this->array[$key] *= $factor;
        }
    }
}

function multiplyArrayOptimized($array, $factor) {
    $observer = new ArrayMultiplyObserver($array);
    EventManager::getInstance()->subscribe($observer);

    foreach ($array as $key => $value) {
        EventManager::getInstance()->notify($factor);
    }

    return $observer->getArray();
}