(dis)advantages to Global Data and Registry-Objects

[Goldeneye]

Trying to improve my script-architecture, I got curious about other ways to pass application-data around aside from using the$GLOBALS array. The only other way I really found was to use an object called a "Registry". I just ended up being confused regarding when which method is better than the other, let alone how to even use a registry-object in my scripts. So my questions are:

- When is it better to use a registry object in place of global data?

- how would you use a registry?

- how would a registry object get passed around, through other objects and functions?

 

Heres the registry I found...

	class registry {
	var $_cache_stack = array();

	function __construct(){
		$this->_cache_stack = array(array());
	}
	function set($key, &$item){
		$this->_cache_stack[0][$key] = &$item;
	}
	function &get($key){
		return $this->_cache_stack[0][$key];
	}
	function isEntry($key){
		return ($this->getEntry($key) !== null);
	}
	function &instance(){
		static $registry = false;
		if (!$registry) $registry = new Registry();
		return $registry;
	}
	function save(){
		array_unshift($this->_cache_stack, array());
		if (!count($this->_cache_stack)) exit('Registry lost!');
	}
	function restore(){
		array_shift($this->_cache_stack);
	}
}

 

[requinix]

$_GLOBALS is basically a Registry itself. Using a class just gives you more flexibility on what you can do.

 

A registry can have a purpose but a lot of the time it's misused. Basically just functions as a store of global variables. So the real question is not which method you should use but why you need to use one.