import java.util.*;

public class VGFeed implements newsFeed{

    ArrayList<VGSubscriber> subs;
    String lastUpdate;

    public VGFeed(){
        subs = new ArrayList<VGSubscriber>();
    }
    @Override
    public void postUpdate(String update){
        lastUpdate = update;

        notifySubscribers();
    }

    @Override
    public void notifySubscribers() {
        for(VGSubscriber sub : subs){
            sub.receiveUpdate(lastUpdate);
        }
    }

    @Override
    public void addSubscriber(VGSubscriber sub){
        subs.add(sub);
    }
}