PHP enumerated string value

class PageSpecial extends AStringEnum
{
    static final function conditions()
    {
        return self::get(__FUNCTION__);
    }

    static final function home()
    {
        return self::get(__FUNCTION__);
    }

    static final function HOMEPAGE()
    {
        return self::home();
    }

    static final function DOMOV()
    {
        return self::get('home');
    }
}

abstract class AStringEnum
{
    private static $instances, $list;
    private $value;

    private function __construct($value)
    {
        $this->value = (string) $value;
    }

    final function __toString()
    {
        return $this->value;
    }

    static final function getList()
    {
        if (is_null(self::$list)) {
            $class = get_called_class();
            $c = new \ReflectionClass($class);
            self::$list = array();

            foreach ($c->getMethods() as $m) {
                $name = strtoupper($m->getName());

                if ($m->isFinal() && $m->isStatic() && !in_array($name, array(
                    'GET', 'GETLIST'
                ))) {
                    self::$list[$name] = (string) $class::$name();
                }
            }
        }

        return self::$list;
    }

    protected static final function get($value)
    {
        $value = (string) $value;

        if (empty(self::$instances[$value])) {
            $class = get_called_class();
            self::$instances[$value] = new $class($value);
        }

        return self::$instances[$value];
    }
}

var_dump(
    PageSpecial::HOME() === PageSpecial::HOMEPAGE() &&
    PageSpecial::HOMEPAGE() === PageSpecial::DOMOV()
);
print_r(PageSpecial::getList());