// Interface for the main product - ConcertTicket
interface ConcertTicket {
    String getDescription();
    double getCost();
}


// A ConcertTicket implementation
class BasicConcertTicket implements ConcertTicket {
    @Override
    public String getDescription() {
        return "Concert ticket";
    }


    @Override
    public double getCost() {
         return 450.0;
    }
}


// The ConcertTicket decorator
abstract class ConcertTicketDecorator implements ConcertTicket {
    private final ConcertTicket decoratedTicket;


    public ConcertTicketDecorator(ConcertTicket decoratedTicket){
        this.decoratedTicket = decoratedTicket;
    }


    public String getDescription() {
        return decoratedTicket.getDescription();
    }


    public double getCost() {
        return decoratedTicket.getCost();
    }
}




// A specific ConcertTicket decorator - VIPSpot
class VIPSpot extends ConcertTicketDecorator {
    public VIPSpot(ConcertTicket decoratedTicket) {
        super(decoratedTicket);
    }


    @Override
    public String getDescription() {
        return super.getDescription() + ", VIP spot";
    }


    @Override
    public double getCost() {
        return super.getCost() + 300.0;
    }
}