Singleton base class

With the so-called "late static binding" feature in PHP 5.3 and the function get_called_class() at hand we can realize a singleton base class. This will alleviate creating singleton classes -the only thing needed is to extend the base class:

  class Logger extends Singleton {
  
    public function log($arg) {
      // ...
    }
  }
  
  Logger::getInstance()->log('Hello');

Base class implementation

  abstract class Singleton {
    private static $instances= array();
    
    private final function __construct() { }
    private final function __clone() { }
    
    public static function getInstance() {
      $id= get_called_class();
      if (!isset(self::$instances[$id])) {
        self::$instances[$id]= new static();
      }
      return self::$instances[$id];
    }
  }

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