Extending singletons in PHP

Question

I\'m working in a web app framework, and part of it consists of a number of services, all implemented as singletons. They all extend a Service class, where the singleton behavio

Answer 1

Had I paid more attention in 5.3 class, I would have known how to solve this myself. Using the new late static binding feature of PHP 5.3, I believe Coronatus' proposition can be simplified into this:

class Singleton {
    protected static $instance;

    protected function __construct() { }

    final public static function getInstance() {
        if (!isset(static::$instance)) {
            static::$instance = new static();
        }

        return static::$instance;
    }

    final private function __clone() { }
}

I tried it out, and it works like a charm. Pre 5.3 is still a whole different story, though.