SM.php

class ServiceManager
{
    protected $cache = array();
    
    protected $factories = array();
    
    public function create($name)
    {
        if (isset($this->factories[$name]) && !isset($this->cache[$name])) {
            $this->cache[$name] = $this->factories[$name]->createService($this);
        }
        
        return $this->cache[$name];
    }
}