1: <?php
 2: 
 3: namespace ModHelper;
 4: 
 5: /**
 6:  * @package ModHelper
 7:  * @since 1.0
 8:  */
 9: trait SingletonTrait
10: {
11:     /**
12:      * Create Singleton instance.
13:      *
14:      * @return Singleton instance
15:      */
16:     final public static function getInstance()
17:     {
18:         static $instance = null;
19: 
20:         if ($instance === null) {
21:             $instance = new static();
22:         }
23: 
24:         return $instance;
25:     }
26: 
27:     /**
28:      * Prevent creating Singleton instance by "new" keyword.
29:      */
30:     final private function __construct()
31:     {
32:     }
33:     
34:     protected function init() 
35:     {
36:     }
37: 
38:     /**
39:      * Prevent cloning Singleton instance.
40:      */
41:     final private function __clone()
42:     {
43:     }
44: 
45:     /**
46:      * Prevent unserializing Singleton instance.
47:      */
48:     final private function __wakeup()
49:     {
50:     }
51: }
52: