note 90360 added to language.oop5.patterns

Here's my singleton class for php 5.3.0: <?php class Singleton { // this must be in every inherited singleton! protected static $_instance; // get the instance final public static function instance() { // create the instance if we don't have one if (empty(static::$_instance)) { $class = get_called_class(); // php 5.3.0 static::$_instance = new $class; } return static::$_instance; } // must protect the constructor protected function __construct() { } // overload __clone final public function __clone() { throw new Exception('Cannot duplicate a singleton.'); } } // a sample extension class Extension extends Singleton { // has to be here, sadly... if only statics were inherited protected static $_instance; protected function __construct() { ... } public function foo() { echo 'foo\n'; } } // example $extension = Extension::instance(); $extension->foo(); // echo's 'foo\n' as expected ?> Having to add "protected static $_instance" to every singleton is somewhat annoying. I tried the obvious alternative and stored all the instances within an array in the Singleton class. I ran Extension::getInstance() 1,000,000 over 10 runs to see which method was faster: Array of $_instances: 3.47s average Individual $_instance: 1.75s average Considering the array of instances only had 1 key to search through, it's reasonable to assume that method would get slower as singletons are added, whereas the method above will always stay the same speed. The difference was enough for me to suffer the minor inconvenience. ---- Server IP: 209.41.74.194 Probable Submitter: 208.107.102.174 ---- Manual Page -- http://www.php.net/manual/en/language.oop5.patterns.php Edit -- https://master.php.net/note/edit/90360 Del: integrated -- https://master.php.net/note/delete/90360/integrated Del: useless -- https://master.php.net/note/delete/90360/useless Del: bad code -- https://master.php.net/note/delete/90360/bad+code Del: spam -- https://master.php.net/note/delete/90360/spam Del: non-english -- https://master.php.net/note/delete/90360/non-english Del: in docs -- https://master.php.net/note/delete/90360/in+docs Del: other reasons-- https://master.php.net/note/delete/90360 Reject -- https://master.php.net/note/reject/90360 Search -- https://master.php.net/manage/user-notes.php