OOP subklasse en extenden

class Site_Filter_Encrypt extends Zend_Filter_Encrypt
{
    public function __construct()
    {
        parent::__construct(Site_Filter_Encrypt::getConfiguration());
    }

    public static function getConfiguration()
    {
        return array(
            'adapter'     => 'openssl',
            'private'     => APPLICATION_PATH . '/keys/priv.pem',
            'public'      => APPLICATION_PATH . '/keys/publ.pem',
            'compression' => 'bz2'
        );
    }
}

class Site_Filter_Decrypt extends Zend_Filter_Decrypt
{
    public function __construct()
    {
        parent::__construct(Site_Filter_Encrypt::getConfiguration());
    }
}

class Site_Filter_Encrypt extends Zend_Filter_Encrypt
{
    public function __construct()
    {
        parent::__construct(Site_Filter_Encrypt::getConfiguration());
    }
 
    public static function getConfiguration()
    {
        return array(
            'adapter'     => 'openssl',
            'private'     => APPLICATION_PATH . '/keys/priv.pem',
            'public'      => APPLICATION_PATH . '/keys/publ.pem',
            'compression' => 'bz2'
        );
    }
}
 
class Site_Filter_Decrypt extends Zend_Filter_Decrypt
{
    public function __construct()
    {
        parent::__construct(Site_Filter_Encrypt::getConfiguration());
    }
}