package horstmann.ch05_invoice;
/**
   This interface describes the tasks that an invoice
   formatter needs to carry out.
 */
public interface InvoiceFormatter
{
	/**
      Formats the header of the invoice.
      @return the invoice header
	 */
	String formatHeader();

	/**
      Formats a line item of the invoice.
      @return the formatted line item
	 */
	String formatLineItem(LineItem item);

	/**
      Formats the footer of the invoice.
      @return the invoice footer
	 */
	String formatFooter();
}