Singleton in PHP

   <?php

       class Singleton
       {
           // The static instance:
           private static $instance;
           // Instance data:
           private $logEnabled;

           // Private construction:
           private final function __construct()
           {
               $this->logEnabled = false;
           }

           // Private instance getter:
           private static function GetInstance()
           {
               if(!isset(self::$instance))
               {
                   self::$instance = new Singleton();
               }
               return self::$instance;
           }

           // Public static methods for accessing the singleton class:

           // In this example, we'll be implementing a basic logging system:
           public static function EnableLogging($state)
           {
               $logger = self::GetInstance();

               $logger->logEnabled = $state;
           }

           public static function LogMessage($message)
           {
               $logger = self::GetInstance();

               if($logger->logEnabled == true)
               {
                   echo $message;
               }
           }
       }