//decoupling: 
//changing the inner impl of MemCache without affecting the 
//consumers...they get what they need without KNOWING or CARING about 
//the inner implementation of MemCache...
 
class MemCache extends BaseCache{
 
	//define("MEM_CACHE_SESSION_KEY", "__memcachesessionkey");	
 
	public function MemCache(){
		//some intitialization here...
	}
 
	public function get($key){
		if (!array_key_exists($key, $_SESSION[MEM_CACHE_SESSION_KEY]))
			return $_SESSION[MEM_CACHE_SESSION_KEY];
 
		//else
		echo "Huston we have a problem!";
	}
 
	public function set($key, $val){
		if (array_key_exists($key, $_SESSION[MEM_CACHE_SESSION_KEY]))
			echo "Huston...just to let you know that an override occurs here to $key with val: $val";
 
		$_SESSION[MEM_CACHE_SESSION_KEY][$key] = $val;
	}
}