import java.awt.Color;
import java.awt.BorderLayout;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
import javax.script.*;

class FileIO extends JFrame implements ActionListener {
   JLabel text;
   JButton button;
   JPanel panel;
   JTextField textField;
   private boolean _clickMeMode = true;

   FileIO() { //Begin Constructor
     text = new JLabel("Text to save to file:");
     button = new JButton("Click Me");
     button.addActionListener(this);
     textField = new JTextField(30);
     panel = new JPanel();
     panel.setLayout(new BorderLayout());
     panel.setBackground(Color.white);
     getContentPane().add(panel);
     panel.add(BorderLayout.NORTH, text);
     panel.add(BorderLayout.CENTER, textField);
     panel.add(BorderLayout.SOUTH, button);
   } //End Constructor

   public void actionPerformed(ActionEvent event){
     ScriptEngineManager manager = new ScriptEngineManager();
     ScriptEngine engine = manager.getEngineByName("jruby");
//Enable the JRuby script engine to invoke a script in a file
     Invocable inv = (Invocable) engine;
     Object obj = null;
     try {
//Open a file reader on the external JRuby script file
       FileReader f = new FileReader("connectivity.rb");
//Evaluate (execute) the script
       engine.eval(f);
//This error is thrown when there is a problem in the script
     } catch (javax.script.ScriptException e) {
       System.out.println("Script Exception");
     } catch(java.io.FileNotFoundException e) {
       System.out.println("Cannot write to text.txt");
       e.printStackTrace();
     }
     Object source = event.getSource();
     if (source == button) {
       if (_clickMeMode){
         try {
//Get application data
          Object text = textField.getText();
//Invoke write function with text parameter
          inv.invokeFunction("write", text);
//Invoke read function and get the return value
          obj = inv.invokeFunction("read");
          }  catch (javax.script.ScriptException e) {
             System.out.println("Script Exception");
             String mess = e.getMessage();
             System.out.println(mess);
          }  catch (java.lang.NoSuchMethodException e) {
             System.out.println("No such method");
             e.printStackTrace();
         }
//Clear text field
          textField.setText("");
//Display data returned from function
          text.setText("Text retrieved from file:");
          if(obj.toString() == null) {
             String empty = null;
             textField.setText(empty);
          } else {
            String s = obj.toString();
            textField.setText(s);
          }
          button.setText("Click Again");
          _clickMeMode = false;
        } else {
          text.setText("Text to save to file:");
          textField.setText("");
          button.setText("Click Me");
          _clickMeMode = true;
        }
    }
 }

 public static void main(String[] args){
   FileIO frame = new FileIO();
   frame.setTitle("Example");
   WindowListener l = new WindowAdapter() {
     public void windowClosing(WindowEvent e) {
       System.exit(0);
     }
   };
   frame.addWindowListener(l);
   frame.pack();
   frame.setVisible(true);
 }
}