How to develop KNIME node with JavaFX

JavaFXDialog.java

package it.pkg;

import java.awt.BorderLayout;
import java.util.concurrent.Callable;
import java.util.concurrent.Semaphore;
import java.util.concurrent.atomic.AtomicReference;

import javax.swing.JPanel;

import org.knime.core.node.InvalidSettingsException;
import org.knime.core.node.NodeDialogPane;
import org.knime.core.node.NodeSettingsRO;
import org.knime.core.node.NodeSettingsWO;
import org.knime.core.node.NotConfigurableException;
import org.knime.core.node.port.PortObjectSpec;

import javafx.application.Platform;
import javafx.embed.swing.JFXPanel;
import javafx.scene.Scene;
import javafx.scene.control.TextField;
import javafx.scene.layout.VBox;

/**
 * Node extension with JavaFX example.
 * 
 * <p>
 * To make this class work, you need to append following settings to Knime.ini.
 * 
 * <pre>
 * -Dosgi.framework.extensions=org.eclipse.fx.osgi
 * -Dorg.osgi.framework.bundle.parent=ext
 * </pre>
 * </p>
 * 
 * @author uphy.jp
 */
public class JavaFXDialog extends NodeDialogPane {

  private TextField count;

  protected JavaFXDialog() {
    super();

    final JPanel panel = new JPanel(new BorderLayout());
    final JFXPanel fxpanel = new JFXPanel();

    runOnJavaFXThread(() -> {
      final VBox vbox = new VBox();
      count = new TextField();
      vbox.getChildren().add(count);
      final Scene scene = new Scene(vbox);
      fxpanel.setScene(scene);
      Platform.setImplicitExit(false);
    });

    panel.add(fxpanel, BorderLayout.CENTER);
    addTab("Options", panel);
  }

  @Override
  protected void saveSettingsTo(NodeSettingsWO settings) throws InvalidSettingsException {
    settings.addInt(TestModel.CFGKEY_COUNT, runOnJavaFXThread(() -> Integer.parseInt(count.getText())));
  }

  @Override
  protected void loadSettingsFrom(NodeSettingsRO settings, PortObjectSpec[] specs) throws NotConfigurableException {
    final int countInt = settings.getInt(TestModel.CFGKEY_COUNT, 100);
    runOnJavaFXThread(() -> count.setText(String.valueOf(countInt)));
  }

  private void runOnJavaFXThread(Runnable task) {
    runOnJavaFXThread(() -> {
      task.run();
      return null;
    });
  }

  private <V> V runOnJavaFXThread(Callable<V> task) {
    Semaphore s = new Semaphore(0);
    AtomicReference<V> ref = new AtomicReference<>();
    Platform.runLater(() -> {
      try {
        V result = task.call();
        ref.set(result);
      } catch (Throwable e) {
        e.printStackTrace();
      }
      s.release();
    });
    try {
      s.acquire();
    } catch (InterruptedException e) {
      e.printStackTrace();
    }
    return ref.get();
  }
}