Question

Just a really quick question about something small. The following is part of a programming assignment for my programming 2 class. It focuses on inheritance and multiple classes. I’ve answered the question but want to consolidate the classes into a main function and actually build something rather than just submitting the bare minimum.

My question is the section of code below. The user runs the program, is presented with a dialog asking him as to what he’s like to add (a CD or a Movie, they’re both separate classes).

What I would like though, is for the user to actually name the specific instance of the class while the program is running. So, the user will click Movie for example, be prompt to enter a name and then next line to use the constructor in the movie class to create a new instance class with the name the user entered? Is this possible? I tried using a simple string x = JOptionpane and then naming the class x also, but it didn’t work. I’m thinking there might be some method that will refer to the string? like contents.x maybe?

thanks in advance!

import javax.swing.JOptionPane;
public class Main 
{

    public static void main (String args [])
    {
    Object[] options = {"Movie",
                "CD",
                "Cancel"};
            int n = JOptionPane.showOptionDialog(null, "Would you like to add an item?","Product",
                        JOptionPane.YES_NO_CANCEL_OPTION,
                            JOptionPane.QUESTION_MESSAGE,
                                null,
                                    options,
                                        options[2]);

    switch(n)
    {
    case 0: 
    String moviet = JOptionPane.showInputDialog("Title:");
    int movieID = Integer.parseInt(JOptionPane.showInputDialog("ID:"));
    Movie moviett = new Movie(moviet, movieID);


    }


    }

}

Answer 1

If it’s not too far beyond your class’ content, you could use a Map<String, Media>¹ to store instances identified by a runtime-specified string.

Map<String, Media> instances = new HashMap<>();
// snip...
String moviet = JOptionPane.showInputDialog("Title:");
int movieID = Integer.parseInt(JOptionPane.showInputDialog("ID:"));
Movie moviett = new Movie(moviet, movieID);
instances.put("some user-provided string", moviett);

---

_{¹Assuming that Movie and CD both extend/implement Media.}