Accessing same HashMap from MainGUI (jDialog) into another jDialog class

Question

Main GUI(jDialog) - creates an instance of a class which has a HashMap (Lets call this HashMapClass) within this GUI. Able to access the methods to return the HashMap inside this class.

Secondary GUI(jDialog) - Wanting to access the same instance of the class which has the HashMap, not create a new instance inside this jDialog. (want to access the same HashMap with the same data inside)

This is what i've tried so far. This is a button from the Main GUI to open up the Secondary GUI.

Main GUI

private HashMapClass hashMapClassNo;

jButton1.addActionListener(new ActionListener() {

    public void actionPerformed(ActionEvent evt) {
        SecondaryGUI sec = new SecondaryGUI(null);
        sec.setModal(true);
        sec.setLocationRelativeTo(null);
        sec.setVisible(true);
    }

    private ActionListener init(HashMapClass hashMapClass) {
         hashMapClass = hashMapClassNo;
         return this;
    }

}.init(hashMapClassNo));

This compiles, but I still cannot access the methods using external method calls, or the HashMaps inside the SecondaryGUI.

How do i access the methods from one jDialog, into another?

Answer 1

You're adding a new method to an anonymous inner class, and that will never work. I'm not even sure what you're trying to achieve with the init() method. Myself, if I want another class to have direct access to an object, I'd pass that object into the other class via a constructor parameter or a setter method.

eg,

jButton1.addActionListener(new ActionListener() {

    public void actionPerformed(ActionEvent evt) {
        SecondaryGUI sec = new SecondaryGUI(hashMapClassNo); // pass it in
        sec.setModal(true);
        sec.setLocationRelativeTo(null);
        sec.setVisible(true);
    }
};

A better solution is to use an MVC design pattern, but that will require more up-front work on your part, but is worth it if this is a large complex program and thus you absolutely need to create highly cohesive low-coupling testable classes.