*/ if ( ! class_exists( '\Cmb2Grid\DesignPatterns\Singleton' ) ) { abstract class Singleton { abstract protected function __construct(); /** * Returns the *Singleton* instance of this class. * * @staticvar Singleton $instance The *Singleton* instances of this class. * * @return Current_Class_Name */ public static function getInstance() { static $instance = null; if ( null === $instance ) { $instance = new static(); } return $instance; } } }