This simple Singleton PHP-Class enables an easy *encapsulating of class attributes and methods* with the benefit of standard Singleton "features" (no need of an instance). The only clue: encapsulating! That enables to hide attributes and even methods for the user of your class (which extends the simple Singleton class). On this way you are able …

Singleton.class.php

class Singleton {
   protected static $inst = null;
   protected static function getInstance($c2i) {
      if(self::$inst === null)
         self::$inst = new $c2i;
      return self::$inst;
   }
}
 

UsageDemoClass-AnySingletonClass.class.php

/**
* This demonstrates the the Singleton Class purpose 
*/
class AnySingletonClass extends Singleton {
 
   private $foo = "bar"; // this is private an can not be accessed via AnySingletonClass::$bar but via the getter and setter AnySingletonClass::setFoo(<nuVal>)
 
   /**
    * @return AnySingletonClass
    */
   private static function i() {
      return self::getInstance(AnySingletonClass);
   }
 
   public static function setFoo($val) {
      self::i()->foo = $val;
   }
 
   public static function getFoo() {
      return self::i()->foo;
   }
 
}