class User
{
    private $name;

    public function getName()
    {
        return $this->name;
    }

    public function setName($newName)
    {
        if($this->validateName($newName))
            $this->name = $newName;
        else
            throw new \Exception('Invalid name');
    }

    private function validateName($name)
    {
        return preg_match('#[a-z]*#iu', $name);
    }
}