private function validateUser(UserInterface $user)
    {
        return $user->isValid($this->username, $this->password, $this->realm);
    }
private function validateUser(UserInterface $user)
    {
        return $user->isValid($this->username, $this->password, $this->realm);
    }
private function validateUser ( UserInterface $ user ) { return $ user -> isValid ( $ this -> username , $ this -> password , $ this -> realm ) ; }
Checks for valid user

@param  User $user
@return bool
Checks for valid user