Discuss Figure 7.26 with regard to the user’s interaction; the screen’s interaction; and the system’s interaction (process).
Answer: The user sees the Registration Screen for the Spring 2012, using the drop box “All Courses” they would select a course and click the button “Add Course”.
The screen would show the representation seen at the top of Figure 7.26 initially. This screen would react to the user’s usage of the drop box (showing a scrollable list of the available courses and showing the course selected). When the user has selected a course and clicked “Add Course” the screen would send the information to the registrationGUI and when the RegistrationGUI returns success it would show the second screen in Figure 7.26.
The system’s interaction shown in Figure 7.26 begins with the RegistrationGUI object passing the registration information to the aSection object. This aSection object needs to check if the student has the prerequisites for the course. If the boolean returned is True then the message Add(aStudent) is sent to students object. Note: another sequence diagram would represent Boolean = False.