package testjavafx;

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;

/**
 *
 * @author scott
 */
public class FxMain extends Application {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        launch(args);
    }
    
    @Override
    public void start(Stage primaryStage) {
        primaryStage.setTitle("Java FX UI Tester - Mneumonic leak");

		HBox root = new HBox();
		ButtonMneumonicTest.replaceButton(root);
		root.getChildren().add(new Label(" <-- Press the button multiple times.  The button is replaced each time, but JavaFX is holding a reference to the old ones."));
        primaryStage.setScene(new Scene(root));
        primaryStage.show();
    }
}

class ButtonMneumonicTest {
	static boolean leakyVersion = true; // change to see how Mneumonics affect object retention
	static int number;
	HBox parent;
	byte [] data = new byte [0x1000000];
	Button b;

	private ButtonMneumonicTest(HBox parent) {
		this.parent = parent;
		number++;
		b = new Button();

		// this is the workaround
		//b.setMnemonicParsing(false);

		if (leakyVersion) {
			// Using this text it leaks
			b.setText("Has_Underscore "+number);
		} else {
			// But with this text it doesn't leak
			b.setText("No Underscore "+number);
		}

		b.setUserData(this);
		b.setOnAction(new EventHandler<ActionEvent>() {

			public void handle(ActionEvent t) {
				Button oldButton = (Button) t.getSource();
				ButtonMneumonicTest oldBigObj = (ButtonMneumonicTest) oldButton.getUserData();
				System.err.println("Done with \"" + oldButton.getText() + "\". Replacing with a new one.");
				// pressing the button makes a new large object that is only reachable via the button itself
				HBox oldParent = oldBigObj.parent;
				replaceButton(oldParent);
			}
		});
	}

	static void replaceButton(HBox parent) {
		ButtonMneumonicTest bigObj = new ButtonMneumonicTest(parent);
		parent.getChildren().setAll(bigObj.b);
	}

}