Example Symfony2 security voter

AdminBarVoter.php

<?php

namespace S2\AppBundle\Security\Voter;

use FOS\UserBundle\Model\UserInterface;
use JMS\DiExtraBundle\Annotation as DI;
use Symfony\Component\Security\Core\Authentication\Token\TokenInterface;
use Symfony\Component\Security\Core\Authorization\Voter\VoterInterface;

/**
 * @DI\Service("s2.security.admin_bar_voter")
 * @DI\Tag("security.voter")
 */
class AdminBarVoter implements VoterInterface
{
    public function supportsAttribute($attribute)
    {
        return $attribute == 'VIEW_ADMIN_BAR';
    }

    public function supportsClass($class)
    {
        return true;
    }

    public function vote(TokenInterface $token, $object, array $attributes)
    {
        $user = $token->getUser();
        if (!$user instanceof UserInterface) {
            return VoterInterface::ACCESS_DENIED;
        }

        foreach ($attributes as $attribute) {
            if (!$this->supportsAttribute($attribute)) {
                continue;
            }

            foreach ($user->getRoles() as $role) {
                if (stripos($role, '_ADMIN') !== false) {
                    return VoterInterface::ACCESS_GRANTED;
                }
            }
        }

        return VoterInterface::ACCESS_ABSTAIN;
    }
}