note 74455 deleted from language.oop5.patterns by colder

Note Submitter: edunreal at gmail dot com Reason: simply wrong ---- I found that using intanceof to check whether the static variable is set, doesn't work. Consider the following example: <?php class Example{ private static $_instance = NULL public static function getInstance(){ if(!self::$_instance instanceof self){ echo "creating new Object"; self::$_instance = new self; } return self::$_instance; } } // Let's initiate an Example object: $obj = Example::getInstance(); // outputs: "creating new Object" // let's try to grab an instance of the Example object $obj = Example::getInstance(); // here we expect nothing to show up, instead, "creating new Object" appears ?> The solution is very simple, use isset instead of instanceof. Probably everyone knew this allready, but i didn't. cheers