<?php
/**
* Multiton class implementing Iterator interface thanks to Tom Schaefer
*/
class Multiton implements Iterator
{
/**
* The list of instances of this class
* @var object
*/
private static $instances = array();
/**
* Returns only one instance of this class per id
* @param string $id
* @return object
*/
public static function GetInstance($id)
{
if (!empty($id))
{
if (!isset(self::$instances[$id]) || !self::$instances[$id] instanceof self)
self::$instances[$id] = new self();
return self::$instances[$id];
}
trigger_error("Empty ID!", E_USER_ERROR);
}
/**
* Removes the instance.
* @param string $id
*/
public function UnsetInstance($id)
{
if (!empty($id))
{
if (isset(self::$instances[$id]) && self::$instances[$id] instanceof self)
unset(self::$instances[$id]);
return true;
}
trigger_error("Empty ID!", E_USER_ERROR);
}
/**
* Private constructor
*/
private function __construct()
{
}
/**
* No serialization allowed
*/
public function __sleep()
{
trigger_error("No serialization allowed!", E_USER_ERROR);
}
/**
* No cloning allowed
*/
public function __clone()
{
trigger_error("No cloning allowed!", E_USER_ERROR);
}
/**
* Implementing Iterator
*/
public function current()
{
return current(self::$instances);
}
public function key()
{
return key(self::$instances);
}
public function next()
{
return next(self::$instances);
}
public function rewind()
{
reset(self::$instances);
}
public function valid()
{
return current(self::$instances) !== false;
}
}
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