Re: Traits and static methods

Am 16.11.2010 18:46, schrieb Simas Toleikis: > p.s. a Singleton-Trait implementation could look like: > > trait Singleton { > public static function getInstance() { ... } > } > > class Child extends Parent { > use Singleton; > } > > Child::getInstance(); This is not really a good example as the getInstance() method alone is not sufficient for a reusable implementation of the Singleton pattern. A trait for a reusable implementation of the Singleton pattern should look more like trait Singleton { private static $uniqueInstance = NULL; protected function __construct() {} private final function __clone() {} public static function getInstance() { if (self::$uniqueInstance === NULL) { self::$uniqueInstance = new Singleton; } return self::$uniqueInstance; } } which of course does not work as traits are stateless and class MySingleton { use Singleton; } MySingleton::getInstance(); results in Access to undeclared static property: MySingleton::$uniqueInstance And rightfully so. Nobody should need a mechanism to make it as easy as pie to clutter the code base with singletons ;-) -- Sebastian Bergmann Co-Founder and Principal Consultant http://sebastian-bergmann.de/ http://thePHP.cc/