PHP7 Singleton

Creational/Singleton/Singleton.php

@@ -2,22 +2,17 @@
 
 namespace DesignPatterns\Creational\Singleton;
 
-/**
- * class Singleton.
- */
 class Singleton
 {
     /**
-     * @var Singleton reference to singleton instance
+     * @var Singleton
      */
     private static $instance;
 
     /**
-     * gets the instance via lazy initialization (created on first usage).
-     *
-     * @return self
+     * gets the instance via lazy initialization (created on first usage)
      */
-    public static function getInstance()
+    public static function getInstance(): Singleton
     {
         if (null === static::$instance) {
             static::$instance = new static();
@@ -27,33 +22,30 @@ class Singleton
     }
 
     /**
-     * is not allowed to call from outside: private!
+     * is not allowed to call from outside to prevent from creating multiple instances,
+     * to use the singleton, you have to obtain the instance from Singleton::getInstance() instead
      */
     private function __construct()
     {
     }
 
     /**
-     * prevent the instance from being cloned.
+     * prevent the instance from being cloned (which would create a second instance of it)
      *
      * @throws SingletonPatternViolationException
-     *
-     * @return void
      */
     final public function __clone()
     {
-        throw new SingletonPatternViolationException('This is a Singleton. Clone is forbidden');
+        throw new \Exception('This is a Singleton. __clone is forbidden');
     }
 
     /**
-     * prevent from being unserialized.
+     * prevent from being unserialized (which would create a second instance of it)
      *
      * @throws SingletonPatternViolationException
-     *
-     * @return void
      */
     final public function __wakeup()
     {
-        throw new SingletonPatternViolationException('This is a Singleton. __wakeup usage is forbidden');
+        throw new \Exception('This is a Singleton. __wakeup is forbidden');
     }
 }