Switch while loop

Question

I have a basic method that implements controlling of application menu using switch

 public void applicationMenu(String input) {
    switch (input) {
        case "1":
            findGroups();
            break;
        case "2":
            findStudentsByCourseName();
            break;
        case "3":
            addNewStudent();
            break;
        case "4":
            deleteStudentById();
            break;
        case "5":
            addStudentToCourse();
            break;
        case "6":
            removeStudentCourse();
            break;
        default:
            printDefault();
            break;
    }
}

I use this method with a while loop to call my application menu

public void callMenu() {
        boolean exit = false;
        while (!exit) {
            viewProvider.printMainMenu();
            String input = viewProvider.readString();
            if (input.equals("7")) {
                exit = true;
            }
            applicationMenu(input);
        }
    }

How can I trigger exit from switch case but keep the structure of two methods at the same time?

I'm not sure it's a good idea but if you really have to keep this structure, maybe you could add a case "7" in your switch that throws an Exception. Then, in your callMenu() method, you exit when you catch the Exception — samdouble
– samdouble, Commented Apr 29, 2020 at 1:31

cybersam · Accepted Answer · 2020-04-29 01:34:09Z

This should work:

public boolean applicationMenu(String input) {
    boolean shouldContinue = true;
    switch (input) {
        case "1":
            findGroups();
            break;
        case "2":
            findStudentsByCourseName();
            break;
        case "3":
            addNewStudent();
            break;
        case "4":
            deleteStudentById();
            break;
        case "5":
            addStudentToCourse();
            break;
        case "6":
            removeStudentCourse();
            break;
        case "7":
            shouldContinue = false;
            break;
        default:
            printDefault();
            break;
    }
    return shouldContinue;
}

...

public void callMenu() {
    while (true) {
        viewProvider.printMainMenu();
        String input = viewProvider.readString();
        if (!applicationMenu(input)) {
            break;
        }
    }
}

pczeus · Accepted Answer · 2020-04-29 01:41:09Z

As stated in comments, you could throw an Exception, but I typically don't like to do that if i'm not in an actual error state. It makes more sense to me to use a return value and evaluate the result to determine if the program should terminate:

    public void callMenu() {
        boolean exit = false;
        while (!exit) {
            viewProvider.printMainMenu();
            exit = applicationMenu(viewProvider.readString());
        }
    }



     public boolean applicationMenu(String input) {
        switch (input) {
            case "1":
                findGroups();
                return false;
            case "2":
                findStudentsByCourseName();
                return false;
            case "3":
                addNewStudent();
                return false;
            case "4":
                deleteStudentById();
                return false;
            case "5":
                addStudentToCourse();
                return false;
            case "6":
                removeStudentCourse();
                return false;
            case "7":
                return true;
            default:
                printDefault();
        }
        return false;
    }

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