public void broadcast(String broadcastMessage){
        Iterator<DCBroadcastReceiver> it = dCBroadcasterSubscribers.iterator();
        while(it.hasNext()) {
            DCBroadcastReceiver subscriber = it.next();
            if (subscriber==null) {
                it.remove();
            } else {
                subscriber.onReceive(broadcastMessage);
            }
        }
    }