public function initialize()
    {
        if (true === $this->hasBeenInitialized) {
            return;
        }

        $this->hasBeenInitialized = true;

        foreach ($this->service as $service) {
            list($serviceClassName, $serviceOptions) = $this->manageServiceData($service);

            $this->serviceInstances[$serviceClassName] = $this->getServiceInstance($serviceClassName, $serviceOptions);
        }
    }