How to send event from child class to parent class

I want to know about sending event from child to parent.
I wrote this code, and if choosing a directory, I can see a first picture in a directory on ImageView.

After pushing a button and selecting a directory, I want to send path to ParentController.
But, now I cannot send because getCurrentPath() is called when creating a window.

ParentController
<!-- language: lang-java -->

@FXML private Button openDirButton;
@FXML private ImageView mainImageView;

@FXML
public void initialize(URL location, ResourceBundle resources) {

    // Choosing Directory Button
    OpenDirectoryButton ODB = new OpenDirectoryButton();
    ODB.getDirSetImageSetListView(openDirButton, mainImageView);
    String currentPath = ODB.getCurrentPath();
    System.out.println(currentPath); // null

ChildController
<!-- language: lang-java -->

public class OpenDirectoryButton {

    public static String path;
    public Button getDirSetImageSetListView(Button button, ImageView imageView) {
        button.setOnAction(actionEvent -> {
            // This is a class I made
            DirectoryChoose DC = new DirectoryChoose();
            // Get a Directory Path
            path = DC.getPath();
            // Get a list of path of images
            imageList = DC.getImageList(path);
            image = new Image("file:///" + path + File.separator + imageList.get(0));
            imageView.setImage(image);
        });
        return button;
    }
    public String getCurrentPath() {
        return path;
    }
}

For using with Events there is several ways.

1)https://github.com/AlmasB/FXEventBus. You could integrate it into your project then might to use to manipulate with events.

2. You could declare your class like static field and send to your child and from child class you will use your fields Not good example to use.

ParentController

in field of class

public static ParentConrtroller instance; // Not good declare field in public
    
    ***
    public void inititalize(URL location, ResourceBundle resources){
     instance = this;
}

Child Controller

ParentController.instance //and every public method of Parent is available for your 

Pass a consumer to getDirSetIgmageSetListView

ParentController

ODB.getDirSetImageSetListView(openDirButton, mainImageView, path->{
    System.out.println(path);
});

ChildController

public Button getDirSetImageSetListView(Button button, ImageView imageView, Consumer<String> pathConsumer) {
    button.setOnAction(actionEvent -> {
        // This is a class I made
        DirectoryChoose DC = new DirectoryChoose();
        // Get a Directory Path
        path = DC.getPath();
        // Get a list of path of images
        imageList = DC.getImageList(path);
        image = new Image("file:///" + path + File.separator + imageList.get(0));
        imageView.setImage(image);
        imageConsumer.accept(path); //execute consumer with your path variable
    });
    return button;
}