Re-implement JavaFX showAndWait [closed] - multithreading

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I want to achieve the functionality of Stage.showAndWait() without using the method itself.
I have an application and I need a way of displaying something within the same stage and block the thread displaying the content until a button is pressed.
The thread displaying the content naturally needs to be tha JavaFX application thread - which of course won't handle the buttons as long as it is blocked.
Stage.showAndWait describes its inner workings as "This method temporarily blocks processing of the current event, and starts a nested event loop to handle other events." I see that the method calls "Toolkit.getToolkit().enterNestedEventLoop(this)", which is pretty implementation specific. Are there any other options? Is functionality like this exposed anywhere in the API?
Edit:
Since my question was misleading, I try to rephrase it more to the point from my current perspective:
Is there a public API for Toolkit.getToolkit().enterNestedEventLoop() and Toolkit.getToolkit().exitNestedEventLoop() ?

Answer 1

For my rephrased question:
Is there a public API for Toolkit.getToolkit().enterNestedEventLoop() and Toolkit.getToolkit().exitNestedEventLoop() ?
Since then the API has been made public in:
javafx.application.Platform.enterNestedEventLoop()

Answer 2

It isn't really clear what you are trying to do, but it sounds like you have some long running process that is building up some kind of data, and then you want the user to control how that built up data is delivered to the screen. In that case, then you need to run a background task to build the data, transfer that data to some element that is available to the FXAT, and then use the action event of a button to move the data onto the screen. Something like this:
public class LongTask extends Application {
StringProperty results = new SimpleStringProperty("");
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) {
primaryStage.setTitle("Hello World!");
TextArea textArea = new TextArea();
BorderPane root = new BorderPane();
root.setCenter(textArea);
Button button = new Button("More Data");
root.setBottom(button);
button.setOnAction(evt -> textArea.setText(results.get()));
primaryStage.setScene(new Scene(root, 300, 250));
primaryStage.show();
Task<Void> sleeper = new Task<Void>() {
#Override
protected Void call() throws Exception {
for (int iteration = 0; iteration < 1000; iteration++) {
try {
Thread.sleep(5000);
int i = iteration;
Platform.runLater(() -> results.set(results.get() + "\nIteration " + i));
} catch (InterruptedException e) {
}
}
return null;
}
};
new Thread(sleeper).start();
}
}
Technically, you don't need to make "results" a property, nor do you need to update it through Platform.runlater(). Using Platform.runlater() guarantees that you won't have concurrency issues with results. Also, if you bind "results" to anything, then you'll need to use Platform.runlater() to modify it.