JavaFX メッセージボックスの作成

//write your package name
package com.mycompany.javafx_messagebox;

//import required libraries
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Alert;
import javafx.scene.control.Alert.AlertType;
import javafx.scene.control.Button;
import javafx.scene.layout.TilePane;
import javafx.stage.Stage;

/**
 * JavaFX App
 */
public class App extends Application {

    @Override
    public void start(Stage stage) {

        // create a tile pane
        TilePane r = new TilePane();
        //add padding
        r.setPadding(new Insets(10, 10, 10, 10));

        // an array of button names
        String[] buttonNames = {"Confirmation MessageBox",
                                "Error MessageBox",
                                "Information MessageBox",
                                "Warning MessageBox"};

        //Show no alert at the startup of the program
        Alert alert = new Alert(AlertType.NONE);


        /*
        a loop to create buttons, define actions when
        they are pressed and add them to the tile pane
        */
        for (String s : buttonNames) {
            Button button = new Button(s);

            button.setOnAction((ActionEvent event) -> {
                if (null != button.getText()) {
                    switch (button.getText()) {
                        case "Confirmation MessageBox":
                            // set alert type, title, content text and then show it
                            alert.setAlertType(AlertType.CONFIRMATION);
                            alert.setTitle("Confirmation MessageBox");
                            alert.setContentText("This is a CONFIRMATION "+
                                                 "message for you!");
                            alert.show();
                            break;
                        case "Error MessageBox":
                            // set alert type, title, content text and then show it
                            alert.setAlertType(AlertType.ERROR);
                            alert.setTitle("Error MessageBox");
                            alert.setContentText("This is an ERROR message for you!");
                            alert.show();
                            break;
                        case "Information MessageBox":
                            // set alert type, title, content text and then show it
                            alert.setAlertType(AlertType.INFORMATION);
                            alert.setTitle("Information MessageBox");
                            alert.setContentText("This is a INFORMATION "+
                                                 "message for you!");
                            alert.show();
                            break;
                        case "Warning MessageBox":
                            // set alert type, title, content text and then show it
                            alert.setAlertType(AlertType.WARNING);
                            alert.setTitle("Warning MessageBox");
                            alert.setContentText("This is a WARNING message for you!");
                            alert.show();
                            break;
                        default:
                            break;
                    }
                }
            });

            //add button
            r.getChildren().add(button);

        }

        // create a scene
        Scene sc = new Scene(r, 640, 50);

        // set the scene
        stage.setScene(sc);

        //show the stage
        stage.show();

    }//end start method

    //main method
    public static void main(String[] args) {
        launch(args);
    }//end main

}//end App class