JavaFX GridPane extend to create a Decimal - Hex - Binary Calculator

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.GridPane;
import javafx.stage.Stage;

public class Main extends Application {

   @Override/*from www  . jav  a  2 s  .  co  m*/
   public void start(Stage primaryStage) throws Exception {

      DecHexBinaryPane pane = new DecHexBinaryPane();

      primaryStage.setTitle("Decimal - Hex - Binary Calculator");
      primaryStage.setScene(new Scene(pane));
      primaryStage.show();
   }

   public static void main(String[] args) {
      Application.launch(args);
   }
}

class DecHexBinaryPane extends GridPane {

   Label lblDecimal = new Label("Decimal:");
   Label lblHex = new Label("Hex:");
   Label lblBinary = new Label("Binary:");

   TextField tfDecimal = new TextField();
   TextField tfHex = new TextField();
   TextField tfBinary = new TextField();

   Integer integer = 0;

   public DecHexBinaryPane() {

      setHgap(10);
      setVgap(10);
      setPadding(new Insets(10, 10, 10, 10));

      TextField[] textFields = new TextField[3];
      // row 0
      add(lblDecimal, 0, 0);
      add(tfDecimal, 1, 0);
      textFields[0] = tfDecimal;
      // row 1
      add(lblHex, 0, 1);
      add(tfHex, 1, 1);
      textFields[1] = tfHex;

      // row 2
      add(lblBinary, 0, 2);
      add(tfBinary, 1, 2);
      textFields[2] = tfBinary;

      for (int i = 0; i < textFields.length; i++) {
         textFields[i].setText("0");
         textFields[i].setAlignment(Pos.CENTER_RIGHT);
      }
      tfDecimal.setOnAction(e -> {
         integer = new Integer(tfDecimal.getText());
         update();
      });
      tfHex.setOnAction(e -> {
         integer = Integer.parseInt(tfHex.getText(), 16);
         update();
      });

      tfBinary.setOnAction(e -> {
         integer = Integer.parseInt(tfBinary.getText(), 2);
         update();
      });
   }

   private void update() {
      tfDecimal.setText(integer.toString());
      tfHex.setText(Integer.toHexString(integer));
      tfBinary.setText(Integer.toBinaryString(integer));
   }
}