    01: /**
    02:    A line item in an invoice.
    03: */
    04: public interface LineItem
    05: {
    06:    /**
    07:       Gets the price of this line item.
    08:       @return the price
    09:    */
    10:    double getPrice();
    11:    /**
    12:       Gets the description of this line item.
    13:       @return the description
    14:    */
    15:    String toString();
    16: }