具有唯一实例的 Symfony2 服务

Question

我需要一些帮助：

我有以下服务：

services.yml 中的服务配置

服务：

xpad.producto_repository:
     class: Xpad\ProductoBundle\Entity\ProductRepository
     factory_service: doctrine.orm.clientes_entity_manager
     factory_method: getRepository
     arguments:
         - Xpad\ProductoBundle\Entity\Product


backend_cliente.producto_filters:
     class: Xpad\BackendClienteBundle\Filters\ProductFilters
     calls:
         - [setRepository, ["@xpad.producto_repository="]]
     scope: container

并且 backend_cliente.producto_filters 的类是：

namespace Xpad\BackendClienteBundle\Filters;

use Xpad\ProductoBundle\Entity\ProductRepository;

class ProductFilters
{
    private $_queryBuilder;


    public function getQueryBuilder()
    {
        return $this->_queryBuilder;
    }

    public function setQueryBuilder($queryBuilder)
    {
        $this->_queryBuilder = $queryBuilder;
    }

    public function setRepository(ProductRepository $productRepository = null)
    {
        if($this->_queryBuilder == null)
        {
            $this->_queryBuilder = $productRepository->createQueryBuilder('p');
        }
    }
}

并且我在我的一个控制器中执行了以下操作：

class ProductController extends Controller
{ 
 ............
    public function indexAction(Request $request)
    {
      //SOME CODE

       $service_filter = $this->container->get('backend_cliente.producto_filters');
       $queryBuilder = $service_filter->getQueryBuilder();

      //SOME OTHER CODE
    }

我的问题是：每当执行 indexAction 时，我都会获得 backend_cliente.producto_filters 服务的新实例，但我不知道为什么。我需要作为单例的唯一实例，因为 A 具有 $_queryBuilder 属性，并且我需要获取它的值，只需在需要时修改它的值即可；

请帮助我不知道我做错了什么。

Answer 1

您必须将类用作服务吗？

为什么不使用单例而不使用服务？像这样：

namespace Xpad\BackendClienteBundle\Filters;

use Xpad\ProductoBundle\Entity\ProductRepository;

class ProductFilters { 
    private $_queryBuilder;
    private static $reference = null;

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

    private function __construct(){}

    public function getQueryBuilder()
    {
        return $this->_queryBuilder;
    }

    public function setQueryBuilder($queryBuilder)
    {
        $this->_queryBuilder = $queryBuilder;
    }

    public function setRepository(ProductRepository $productRepository = null)
    {
        if($this->_queryBuilder == null)
        {
            $this->_queryBuilder = $productRepository->createQueryBuilder('p');
        }

    }
}

然后调用它：

...
$filter = ProductFilters::getInstance();
...