I am reading about Patterns in OOP and came across this code for the singleton pattern:
class Singleton
{
/**
* @var Singleton reference to singleton instance
*/
private static $instance;
/**
* gets the instance via lazy initialization (created on first usage)
*
* @return self
*/
public static function getInstance()
{
if (null === static::$instance) {
static::$instance = new static;
}
return static::$instance;
}
/**
* is not allowed to call from outside: private!
*
*/
private function __construct()
{
}
/**
* prevent the instance from being cloned
*
* @return void
*/
private function __clone()
{
}
/**
* prevent from being unserialized
*
* @return void
*/
private function __wakeup()
{
}
}
The part in question is static::$instance = new static;
. What exactly does new static
do or how does this example work. I am familiar with your average new Object
but not new static
. Any references to php documentation would help greatly.