Factory

<?php
class Factory {
    private $_store  = array();
    function __construct(){
    }
    public function get($key) {
        if(isset($this->_store[$key])) {
            return $this->_store[$key];
        }
        return null;
    }
    public function set($key, $value = null) {
        if($key){
            $this->_store[$key] = $value;
        }
    }
}


$f1 = new Factory();
$f2 = new Factory();
$f1->set('f1','f1');
$f2->set('f2','f2');
var_dump($f1,$f2,$f1===$f2);