PHP中从方法返回值动态实例化类并传递构造函数参数

// 示例：具体的邮件处理类
class ProductMail {
    private $data;

    public function __construct($data) {
        $this->data = $data;
        echo "ProductMail instantiated with data: " . json_encode($this->data) . "\n";
    }

    public function to($email) {
        echo "Sending mail to: " . $email . "\n";
        return $this;
    }

    public function send() {
        echo "Mail sent!\n";
    }
}

// 示例：具体的通知类
class ProductNotification {
    public function mail(): string {
        return ProductMail::class; // 返回类名字符串
    }
}

// 错误的尝试：直接调用方法进行实例化
class BaseNotification {
    public function toMail($data, $email) {
        // 这种方式是错误的，因为 $this->mail() 返回的是一个字符串，
        // 而不是一个可直接实例化的“属性”或“类型”
        // return (new $this->mail())->to($email)->send(); // 编译错误或运行时错误
        // 如何传递 $data 给构造函数也是一个问题
    }
}

// 示例：具体的邮件处理类 (与上面相同)
class ProductMail {
    private $data;

    public function __construct($data) {
        $this->data = $data;
        echo "ProductMail instantiated with data: " . json_encode($this->data) . "\n";
    }

    public function to($email) {
        echo "Sending mail to: " . $email . "\n";
        return $this;
    }

    public function send() {
        echo "Mail sent!\n";
    }
}

class OrderMail {
    private $data;

    public function __construct($data) {
        $this->data = $data;
        echo "OrderMail instantiated with data: " . json_encode($this->data) . "\n";
    }

    public function to($email) {
        echo "Sending mail to: " . $email . "\n";
        return $this;
    }

    public function send() {
        echo "Mail sent!\n";
    }
}

// 示例：具体的通知类 (与上面相同)
class ProductNotification extends BaseNotification {
    public function mail(): string {
        return ProductMail::class;
    }
}

class OrderNotification extends BaseNotification {
    public function mail(): string {
        return OrderMail::class;
    }
}

// 修正后的 BaseNotification 类
abstract class BaseNotification {
    // 抽象方法，强制子类实现 mail()
    abstract public function mail(): string;

    public function toMail($data, $email) {
        // 1. 调用 mail() 方法获取具体的类名字符串
        $mail_class = $this->mail();

        // 2. 使用获取到的类名字符串动态实例化，并传递数据给构造函数
        $mail_instance = new $mail_class($data);

        // 3. 继续链式调用其他方法
        return $mail_instance->to($email)->send();
    }
}

// 使用示例
echo "--- Product Notification ---\n";
$productNotification = new ProductNotification();
$productData = ['product_id' => 123, 'name' => 'Laptop'];
$productNotification->toMail($productData, 'user@example.com');

echo "\n--- Order Notification ---\n";
$orderNotification = new OrderNotification();
$orderData = ['order_id' => 456, 'amount' => 99.99];
$orderNotification->toMail($orderData, 'admin@example.com');