must be available though buttons on the screen. The input characters
required in the use cases are all decimal digits. Thus the graphical interface
shall have a section with buttons corresponding to the numbers, plus a
comma and a delete button.
The initial screen that allows connection to the server should look like
Figure 14.6 (top). After connection, the layout of the screen is reconfigured
to support the operations performed during the acquisition use case. The
screen should appear as in Figure 14.6 (bottom).
The second non-functional requirement is the presence of a bar code
reader. It can read both product codes and customer codes. The prototype
we develop will emulate the bar code reader in a separate window, shown in
Figure 14.7. The pressure on a button simulates the scanning of a bar code
from the reader.
The design of the interface is very simple. It consists of two main classes that
represent the two windows identified in the analysis above: the counter
terminal interface and the bar code reader emulation window.
Figure 14.7 Bar code reader window. Copyright © 2005 Sun Microsystems, Inc. All rights
reserved. Reproduced by permission of Sun Microsystems, Inc.