//dealing with encapsulation....
class MemCache{
 
	private $mem;
 
	public function MemCache(){
		//some intitialization here...
		$this->mem = array();
	}
 
	public function get($key){
		if (!array_key_exists($key, $this->mem))
			return $this->mem[$key];
 
		//else
		echo "Huston we have a problem!";
	}
 
	public function set($key, $val){
		if (array_key_exists($key, $this->mem))
			echo "Huston...just to let you know that an override occurs here to $key with val: $val";
 
		$this->mem[$key] = $val;
	}
}