Symfony2 using security.contex in login listener

LoginListener.php

<?php

// option 1: to replace/extend DefaultAuthenticationSuccessHandler
// http://www.reecefowell.com/2011/10/26/redirecting-on-loginlogout-in-symfony2-using-loginhandlers/
// http://stackoverflow.com/questions/15918617/symfony2-extending-defaultauthenticationsuccesshandler
//
// option 2: to use 2 listeners, 1 for checking admin and second to observer response event and change it
// http://forum.symfony-project.org/viewtopic.php?t=37383

namespace My\UserBundle\EventListener;

use Symfony\Component\Security\Core\Event\AuthenticationEvent;
use Symfony\Component\Security\Core\SecurityContext;
use Symfony\Component\HttpFoundation\RedirectResponse;
use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
use Symfony\Bundle\FrameworkBundle\Routing\Router;

class LoginListener
{
    /**
     * @var string
     */
    protected $redirect;

    /**
     * Router
     *
     * @var Router
     */
    protected $router;

    /**
     * @var SecurityContext
     */
    protected $securityContext;

    /**
     * @param SecurityContext $securityContext
     * @param Router $router The router
     */
    public function __construct(SecurityContext $securityContext, Router $router)
    {
        $this->securityContext = $securityContext;
        $this->router = $router;
    }

    public function handle(AuthenticationEvent $event)
    {
        $token = $event->getAuthenticationToken();
        $this->securityContext->setToken($token);

        if ($this->securityContext->isGranted(array('ROLE_ADMIN'))) {
            $this->redirect = 'admin';
        }

        $this->securityContext->setToken(null);
    }

    public function onKernelResponse(FilterResponseEvent $event)
    {
        if (null !== $this->redirect) {
            $url = $this->router->generate($this->redirect);
            $event->setResponse(new RedirectResponse($url));
        }
    }
}

security.yml

security:
    encoders:
        FOS\UserBundle\Model\UserInterface: sha512

    role_hierarchy:
        ROLE_ADMIN:       ROLE_USER
        ROLE_SUPER_ADMIN: ROLE_ADMIN

    providers:
        fos_userbundle:
            id: fos_user.user_provider.username_email

    firewalls:
        main:
            pattern: ^/
            form_login:
                default_target_path: /
                always_use_default_target_path: true
                provider: fos_userbundle
                csrf_provider: form.csrf_provider
            logout:       true
            anonymous:    true

    access_control:
        - { path: /_wdt/.*, role: IS_AUTHENTICATED_ANONYMOUSLY }
        - { path: /_profiler/.*, role: IS_AUTHENTICATED_ANONYMOUSLY }
        - { path: ^/login$, role: IS_AUTHENTICATED_ANONYMOUSLY }
        - { path: ^/register, role: IS_AUTHENTICATED_ANONYMOUSLY }
        - { path: ^/resetting, role: IS_AUTHENTICATED_ANONYMOUSLY }
        - { path: ^/admin, role: ROLE_ADMIN }
        - { path: ^/, role: ROLE_USER }

services.yml

services:
    my.login:
        class: My\UserBundle\EventListener\LoginListener
        arguments: [@security.context, @router]
        tags:
            - { name: kernel.event_listener, event: security.authentication.success, method: handle }
            - { name: kernel.event_listener, event: kernel.response, method: onKernelResponse }