Notify JavaFX about Java objects changes.

Question

Good day. I'm trying to solve the problem with willions solutions. Unfortunately, I don't understand some part of them. The rest part of solutions doesn't work properly.
The idea is very simple and naive.
I have a rather complicated Java model (many Java beans live in runtime.)
This Java model is wrapped with single controller (ModelController).
ModelController is a singletone. It has several methods:
1. addObject
2. updateObject
3. removeObject
4. getObject (can't be modified, read-only mode)
5. getModel (can't be modified, read-only mode)
Also I have a JavaFX application which asks ModelController for model (*ModelController.getInstance().getModel()*) and displays this huge model.
The problem is: i would like to send a notification to JavaFX part with message:
Command{
changeType=CREATE|UPDATE|DELETE
objectId=someId
It will be an object with two fields.
So JavaFX part will go to ModelController.getInstance().getObject("someId") and repaint it.
What is the best way for establishing such link?
Is it possible to bind JavaFX to some variable of type Command.
Java-part will change this variable with new value, JavaFX part will go to controller and ask for object in response.
Please, help me.

Answer 1

JavaFX classes can extend Java classes and interfaces. So just have a listener interface that you implement in JavaFX.
class Model {
    ModelListener listener;
    public void addListener(ModelListener l) { listener = l; }
    void someFunctionThatUpdatesTheModel() {
        listener.notify();
interface ModelListener {
    void notify();
// In JavaFX...
class MyModelListener extends ModelListener {
    override function notify():Void {
        // do something useful
var model = new Model();
model.addListener(MyModelListener{});