在 PHP Symfony 4.4 中编写一个类，使用设计模式 Factory Method 来实例化 Service 类

Question

使用激活自动装配的 Symfony 4.4，我想使用设计模式 FactoryMethod 实例化一个类。

实例化的类是一个将自动装配的参数传递给构造函数的服务。

如果在工厂方法内部实例化每种类型的类的构造函数都相同，则效果很好。

但是，每个要实例化的服务都必须自动装配一些特定的服务才能工作。

我发现我们可以使用“setter 依赖注入”。描述它的文章：

• https://symfonycasts.com/screencast/symfony-fundamentals/logger-trait
• https://symfony.com/doc/4.4/service_container/injection_types.html#setter-injection

我试图实现setter依赖注入，但里面的代码从未执行过。

考虑到文章，我们应该在调用 __construct 方法后立即使用 PHPDoc“@required”输入设置器（据我了解）。

它不适用于我的代码（见下文）。

我的实现是否正确？

有没有更好的方法？

我的代码如下：

// Controller
/**
 *@Route("/my_action/{param}")
 */
public function my_action (ThingManagerFactory $thingManagerFactory, $param)
{
    $thingManager = $thingManagerFactory->get($param);
    $thingManager->doSomething();
}


// ThingManagerFactory

class ThingManagerFactory
{
    private $firstManager;
    private $secondManager;
    private $thirdManager;

    public function __construct(FirstManager $firstManager, SecondManager $secondManager, ThirdManager $thirdManager)
    {
        $this->firstManager = $firstManager;
        $this->secondManager = $secondManager;
        $this->thirdManager = $thirdManager;
    }

    public function get($param): ThingManagerInterface
    {
        if($param == 1) {
            return new Thing1Manager(
                $this->firstManager,
                $this->secondManager,
                $this->thirdManager,
            );
        } elseif($param == 2) {
            return new Thing2Manager(
                $this->firstManager,
                $this->secondManager,
                $this->thirdManager,
            );
        }

        throw new \InvalidArgumentException("...");
    }
}


// ThingManagerInterface
interface ThingManagerInterface
{
    public function __construct(
            $this->firstManager,
            $this->secondManager,
            $this->thirdManager,
        );
    public function doSomething();
}


// Thing1Manager
class Thing1Manager implements ThingManagerInterface
{
    (...)
    private $spec1Manager;

    public function __construct(
            $this->firstManager,
            $this->secondManager,
            $this->thirdManager,
        )
    {
        (...)
    }

    /**
     * @required
     */
    public function setSpecificManager(Spec1Manager $spec1Manager)
    {
        // this code is never called
        $this->spec1Manager = $spec1Manager;
    }

    public function doSomething()
    {
        // we pass here before going into setSpecificManager
        (...)
    }
}


// Thing2Manager class
// is similar to Thing1Manager with multiple other specific managers.

感谢您的帮助。

Answer 1

为了在 Symfony 中使用设计模式工厂方法，请使用服务定位器在控制器外部提供自动装配。 重构代码如下：

// Controller
/**
 *@Route("/my_action/{param}")
 */
public function my_action (ThingManagerFactory $thingManagerFactory, $param)
{
    $thingManager = $thingManagerFactory->get($param);
    $thingManager->doSomething();
}


// ThingManagerFactory
use App\Locator\ThingLocator;
class ThingManagerFactory
{
    private $locator;

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

    public function get($param): ThingManagerInterface
    {
        if($param == 1) {
            return $this->locator->get(Thing1Manager::class);
        } elseif($param == 2) {
            return $this->locator->get(Thing2Manager::class);
        }

        throw new \InvalidArgumentException("...");
    }
}


// ServiceLocatorInterface
interface ServiceLocatorInterface
{
    public function get(string $id);
}


// ThingLocator
class ThingLocator implements ServiceLocatorInterface, ServiceSubscriberInterface
{
    private $locator;

    public function __ construct(ContainerInterface $locator)
    {
        $this->locator = $locator;
    }

    public function get(string $id)
    {
        if (!$this->locator->has($id)) {
            throw new \Exception("The entry for the given '$id' identifier was not found.");
        }

        try {
            return $this->locator->get($id);
        } catch (ContainerExceptionInterface $e) {
            throw new \Exception("Failed to fetch the entry for the given '$id' identifier.");
        }
    }

    public static function getSubscribedServices()
    {
        return [
            Thing1Manager::class,
            Thing2Manager::class,
        ];
    }
}


// ThingManagerInterface
interface ThingManagerInterface
{
    public function doSomething();
}


// Thing1Manager
class Thing1Manager implements ThingManagerInterface
{
    // ...
    private $spec1Manager;

    public function __construct($firstManager, $secondManager, $thirdManager, $spec1Manager)
    {
        // ...
    }

    // This setter is no more needed. This manager can be added to the constructor method.
    // **
    // * @required
    // */
    //public function setSpecificManager(Spec1Manager $spec1Manager)
    //{
        // if not commented, this code would be called thanks to the Service Locator (which is a Symfony Service Container)
    //    $this->spec1Manager = $spec1Manager;
    //}

    public function doSomething()
    {
        // ...
    }
}