How to realize singleton pattern

What this article shares with you is about how to realize the singleton model. The editor thinks it is very practical, so I share it with you. I hope you can get something after reading this article. Let's take a look at it with the editor.

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/ / final modifier class, then Single class cannot be inherited by subclass

Final class Single {

/ / declare private static variables

Private static $instance

/ / the constructor private function _ _ construct () {} / / gets the singleton object function static public function getInstance () {if (! is_null (self::$instance)) {return self::$instance;} else {return self::$instance = new Single ();}} / / disables the cloning of objects. The private function _ clone () {} is reported when the clone keyword is used.

}

$obj1 = Single::getInstance ()

Var_dump ($obj1)

$obj2 = Single::getInstance ()

Var_dump ($obj2)

/ / an error will be reported here

$obj3 = clone $obj2

Var_dump ($obj3)

The above is how to achieve the singleton model, the editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.