private void handleDisplay()
    {
        //prompt user
        System.out.println("\n--Display Course Sections--");
        if (dataModel.isEmpty())
        {
            System.out.println("No courses stored. Nothing to display.");
            return;
        }
        System.out.println("Stored courses:");
        for (String str : dataModel.getCourseSet())
        {
            System.out.println(str);
        }
        System.out.println();
        System.out.println("Specify which course to display, or enter \"ALL\"");
        String input = getUserInput();  //TODO: Sanitize
        if (input.equalsIgnoreCase("ALL"))
        {
            for (String str : dataModel.getCourseSet())
                printSections(dataModel.getSections(str));
        }
        else
        {
            printSections(dataModel.getSections(input));
        }
    }