Error UserInterFace - Users.php

<?php

namespace App\AdminBundle\Entity;

use Symfony\Component\Security\Core\User\UserInterface;
use Doctrine\Common\Collections\ArrayCollection;
use DateTime as DateTime;

use Doctrine\ORM\Mapping as ORM;

/**
 * App\AdminBundle\Entity\Users
 */
class Users implements UserInterface
{
    /**
     * @var integer $id
     */
    private $id;

    /**
     * @var string $name
     */
    private $name;

    /**
     * @var string $password
     */
    private $password;

    /**
     * @var string $salt
     */
    private $salt;

    /**
     * @var string $username
     */
    private $username;

    /**
     * @var datetime $cdate
     */
    private $cdate;

    /**
     * @var datetime $mdate
     */
    private $mdate;

    /**
     * @var App\AdminBundle\Entity\Roles
     */
    private $role;

    public function __construct()
    {
        $this->role = new \Doctrine\Common\Collections\ArrayCollection();
        $this->cdate = new \DateTime();
        $this->mdate = new \DateTime();
    }

    /**
     * Get id
     *
     * @return integer
     */
    public function getId()
    {
        return $this->id;
    }

    /**
     * Set name
     *
     * @param string $name
     */
    public function setName($name)
    {
        $this->name = $name;
    }

    /**
     * Get name
     *
     * @return string
     */
    public function getName()
    {
        return $this->name;
    }

    /**
     * Set password
     *
     * @param string $password
     */
    public function setPassword($password)
    {
        $this->password = $password;
    }

    /**
     * Get password
     *
     * @return string
     */
    public function getPassword()
    {
        return $this->password;
    }

    /**
     * Set salt
     *
     * @param string $salt
     */
    public function setSalt($salt)
    {
        $this->salt = $salt;
    }

    /**
     * Get salt
     *
     * @return string
     */
    public function getSalt()
    {
        return $this->salt;
    }

    /**
     * Set username
     *
     * @param string $username
     */
    public function setUsername($username)
    {
        $this->username = $username;
    }

    /**
     * Get username
     *
     * @return string
     */
    public function getUsername()
    {
        return $this->username;
    }

    /**
     * Set cdate
     *
     * @param datetime $cdate
     */
    public function setCdate($cdate)
    {
        $this->cdate = $cdate;
    }

    /**
     * Get cdate
     *
     * @return datetime
     */
    public function getCdate()
    {
        return $this->cdate;
    }

    /**
     * Set mdate
     *
     * @param datetime $mdate
     */
    public function setMdate($mdate)
    {
        $this->mdate = $mdate;
    }

    /**
     * Get mdate
     *
     * @return datetime
     */
    public function getMdate()
    {
        return $this->mdate;
    }

    /**
     * Add role
     *
     * @param App\AdminBundle\Entity\Roles $role
     */
    public function addRoles(\App\AdminBundle\Entity\Roles $role)
    {
        $this->role[] = $role;
    }

    /**
     * Get role
     *
     * @return Doctrine\Common\Collections\Collection
     */
    public function getRole()
    {
        return $this->role;
    }

    /**
     * Get user roles
     */
    public function getUserRoles()
    {
        return $this->getRole();
    }

    /**
     * Get roles
     *
     * @return Array
     */
    public function getRoles()
    {
        return $this->getUserRoles()->toArray();
    }

    /**
     * Erases the user credentials.
     */
    public function eraseCredentials()
    {

    }

    /**
     * Compares this user to another to determine if they are the same.
     *
     * @param UserInterface $user The user
     * @return boolean True if equal, false othwerwise.
     */
    public function equals(UserInterface $user)
    {
        if( $user->getUsername() != $this->getUsername() )
            return false;
        return true;
    }
}