Param converter sans annotations

MonParamConverter.php

<?php

namespace MonVendor\MonBundle\Controller;

use MonVendor\MonBundle\Gestion\DemandeHelper;
use MonVendor\MonBundle\Gestion\Entity\Aide;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\ParamConverter;
use Sensio\Bundle\FrameworkExtraBundle\Request\ParamConverter\ParamConverterInterface;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;

/**
 * Param converter for misc. business entities
 */
class MonParamConverter implements ParamConverterInterface
{
    private $helper;

    /**
     * Default constructor
     *
     * @param Service $service
     */
    public function __construct(DemandeHelper $helper)
    {
        $this->helper = $helper;
    }

    /**
     * {@inheritdoc}
     */
    public function apply(Request $request, ParamConverter $configuration)
    {
        $param = $configuration->getName();

        if (!$request->attributes->has($param)) {
            return false;
        }

        $id = $request->attributes->get($param);
        $object = null;

        if (!$id && $configuration->isOptional()) {
            return false;
        }

        try {
            switch ($configuration->getClass()) {

                case Aide::class:
                    if (!$this->helper->aideExists($id)) {
                        throw new \InvalidArgumentException();
                    }
                    $object = $this->helper->getAide($id, true);
                    break;
            }
        } catch (\InvalidArgumentException $e) {
            throw new NotFoundHttpException('Not Found.', $e);
        }

        $request->attributes->set($param, $object);

        return true;
    }

    /**
     * {@inheritdoc}
     */
    public function supports(ParamConverter $configuration)
    {
        switch ($configuration->getClass()) {

            case Aide::class:
                return true;
        }

        return false;
    }
}

services.yml

services:
      mon_appli.mon_param_converter:
            # Pas besoin qu'il soit publique
            public: false
            class: MonVendor\MonBundle\Controller\MonParamConverter
            # Tes arguments, c'est un service
            arguments: ['...']
            # Le tag magique qui fait que ça marche
            tags: [{name: request.param_converter, priority: 1024, converter: mon_appli.mon_param_converter}]