DRY：如何在 Symfony2 项目的多个实体中使用此代码？特质？

Question

我有这段重复的代码，将在我的 Symfony2 项目中的多个实体中使用，所以如果可能的话，当然可以应用某种 DRY，我正在考虑 PHP Traits。

private static $preDeletedEntities;// static array that will contain entities due to deletion.
private static $deletedEntities;// static array that will contain entities that were deleted (well, at least the SQL was thrown).

/**
 * This callback will be called on the preRemove event
 * @ORM\PreRemove
 */
public function entityDueToDeletion()
{
    // This entity is due to be deleted though not deleted yet.
    self::$preDeletedEntities[] = $this->getId();
}

/**
 * This callback will be called in the postRemove event
 * @ORM\PostRemove
 */
public function entityDeleted()
{
    // The SQL to delete the entity has been issued. Could fail and trigger the rollback in which case the id doesn't get stored in the array.
    self::$deletedEntities[] = $this->getId();
}

public static function getDeletedEntities()
{
    return array_slice(self::$preDeletedEntities, 0, count(self::$deletedEntities));
}

public static function getNotDeletedEntities()
{
    return array_slice(self::$preDeletedEntities, count(self::$deletedEntities)+1, count(self::$preDeletedEntities));
}

public static function getFailedToDeleteEntity()
{
    if(count(self::$preDeletedEntities) == count(self::$deletedEntities)) {
        return NULL; // Everything went ok
    }

    return self::$preDeletedEntities[count(self::$deletedEntities)]; // We return the id of the entity that failed.
}

public static function prepareArrays()
{
    self::$preDeletedEntities = array();
    self::$deletedEntities = array();
}

这是我想到的代码：

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\HasLifecycleCallbacks()
 */
trait DeleteLifeCycleCallbacksTrait
{
    // write things here
}

但是注释会应用于实体吗？可以吗？你会怎么做才能避免重复代码？

编辑：试图找到最佳方法

从 @Cerad 用户那里得到一些想法，因为正如文档所说，生命周期事件侦听器比简单的生命周期回调更强大，那么我将开始使用它们。

所以，首先，Lifecycle Callbacks|Listener|Suscribers 的目的是存储每个持久对象的 ID，以便我可以通过某种方式获取它并从控制器发送回视图。作为一个简单的视觉示例，假设我从视图向控制器发送了这个值数组(1, 2, 3, 4, 5)，并且由于某种 X 原因，只有 1 ,4 和 5 被持久化（意味着从 DB 中完全删除）到 DB，对吗？

还可以说，我将在Producto 实体中使用事件侦听器。因此，无需测试并仅从示例中获取代码，Listener 的代码应该是这样的：

use Doctrine\ORM\Event\LifecycleEventArgs;
use Entity\Producto;

class StoreDeletedIds
{
    private $deletedItems = []; 

    public function postDelete(LifecycleEventArgs $args)
    {
        $entity = $args->getEntity();
        $entityManager = $args->getEntityManager();

        if ($entity instanceof Producto) {
            array_push($deletedItems, $entity->getId());
        }
    }
}

我的问题|对此的疑问是：

• 上面的代码好还是不好？
• 每次 Doctrine 调用侦听器时是否都会清理 $deletedItems？
• 如何返回 $deletedItems 以便在控制器上捕获它并发送回视图？
• 我是否也需要定义订阅者？为什么？

这对我来说是新话题，所以我需要一些建议

Answer 1

以下@PeterPopelyshko评论这是我自带的解决方案，只需定义一个抽象类Model\DeleteLifeCycleCallbacks.php并将代码放入：

use Doctrine\ORM\Mapping as ORM; // not so sure if this is need here

abstract class DeleteLifeCycleCallbacks
{
    private static $preDeletedEntities;// static array that will contain entities due to deletion.
    private static $deletedEntities;// static array that will contain entities that were deleted (well, at least the SQL was thrown).

    /**
     * This callback will be called on the preRemove event
     * @ORM\PreRemove
     */
    public function entityDueToDeletion()
    {
        // This entity is due to be deleted though not deleted yet.
        self::$preDeletedEntities[] = $this->getId();
    }

    /**
     * This callback will be called in the postRemove event
     * @ORM\PostRemove
     */
    public function entityDeleted()
    {
        // The SQL to delete the entity has been issued. Could fail and trigger the rollback in which case the id doesn't get stored in the array.
        self::$deletedEntities[] = $this->getId();
    }

    public static function getDeletedEntities()
    {
        return array_slice(self::$preDeletedEntities, 0, count(self::$deletedEntities));
    }

    public static function getNotDeletedEntities()
    {
        return array_slice(self::$preDeletedEntities, count(self::$deletedEntities)+1, count(self::$preDeletedEntities));
    }

    public static function getFailedToDeleteEntity()
    {
        if(count(self::$preDeletedEntities) == count(self::$deletedEntities)) {
            return NULL; // Everything went ok
        }

        return self::$preDeletedEntities[count(self::$deletedEntities)]; // We return the id of the entity that failed.
    }

    public static function prepareArrays()
    {
        self::$preDeletedEntities = array();
        self::$deletedEntities = array();
    }
}

然后按如下方式使用：

/**
 * @ORM\Entity
 * @ORM\HasLifecycleCallbacks()
 */
class Producto extends Model\DeleteLifeCycleCallbacks
{
    // entity methods and properties here
}

Answer 2

不要

业务逻辑不属于实体。

Traits 也无济于事，因为虽然复制代码是一件坏事，但滥用 Traits imo 更糟糕。

我曾经想知道我是否应该使用特征并在 codereview (https://codereview.stackexchange.com/a/74195/56686) 上发布了一个问题。我还没有在我的应用程序中偶然发现一个有效的特征用例。

提供服务

我建议您提供服务并将您的逻辑放在那里。 文档：http://symfony.com/doc/current/book/service_container.html

因为你不能从学说生命周期回调中调用 symfony 服务，你必须放弃那些。

您可能不想启动您选择的搜索引擎来寻找分步教程。