Restore previously serialized JFrame-object, how?

Question

Hi all. I have managed to serialize my very basic GUI-object containing a JTextArea and a few buttons to a file 'test.ser'.

Now, I would like to completely restore the previously saved state from 'test.ser', but seem to have a misconception of how to properly deserialize an objects state.

The class MyFrame creates the JFrame and serializes it.

public class MyFrame extends JFrame implements ActionListener {


 // Fields
 JTextArea textArea;
 String title;
 static MyFrame gui = new MyFrame();
 private static final long serialVersionUID = 1125762532137824262L;


 /**
  * @param args
  */
 public static void main(String[] args) {
  // TODO Auto-generated method stub
  gui.run();
 }

 // parameterless default contructor
 public MyFrame() {

 }

 // constructor with title
 public MyFrame(String title) {

 }

 // creates Frame and its Layout
 public void run() {

  JFrame frame = new JFrame(title);
  JPanel panel_01 = new JPanel();
  JPanel panel_02 = new JPanel();

  JTextArea textArea = new JTextArea(20, 22);
  textArea.setLineWrap(true);

  JScrollPane scrollPane = new JScrollPane(textArea);

  scrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED);

  panel_01.add(scrollPane);



  // Buttons
  JButton saveButton = new JButton("Save");
  saveButton.addActionListener(this);
  JButton loadButton = new JButton("Load");
  loadButton.addActionListener(this);


  panel_02.add(loadButton);
  panel_02.add(saveButton);
  // Layout
  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  frame.getContentPane().add(BorderLayout.CENTER, panel_01);
  frame.getContentPane().add(BorderLayout.SOUTH, panel_02);

  frame.setSize(300, 400);
  frame.setVisible(true);
 }

 /*
  * 
  */
 public void serialize() {

  try {
   ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("test.ser"));
   oos.writeObject(gui);
   oos.close();
  } catch (Exception e) {
   // TODO: handle exception
   e.printStackTrace();
  }
 }


 public void actionPerformed(ActionEvent ev) {
  System.out.println("Action received!");
  gui.serialize();
 }

}

Here I try to do the deserialization:

public class Deserialize {
 static Deserialize ds;
 static MyFrame frame;



 public static void main(String[] args) {
  try {
   ObjectInputStream ois = new ObjectInputStream(new FileInputStream("test.ser"));
    frame = (MyFrame) ois.readObject();
    ois.close();
  } catch (FileNotFoundException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (ClassNotFoundException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }

Maybe somebody could point me into the direction where my misconception is? Thx in advance!

Answer 1

What happens? Are you getting an exception? From the looks of the code ds is never initialised. I believe, once deserialised, you will need to show the frame with frame.setVisible(true);. As always, Swing (and in fact AWT) should be used only on the AWT Event Dispatch Thread (EDT) - use java.awt.EventQueue.invokeLater.

Generally using statics is not a good idea. Nor is serialising GUI components. final is good, and will, for the most part, make sure instance and static fields are initialised.

Answer 2

Hm, maybe I should rephrase my inital question:

How would you guys write a class, which deserializes and restores the previously serialized gui-elements to their previously serialized state? The way I am doing it right now seems to have more than one flaw in its concept, right?

Answer 3

As says in every javadoc swing component, the preferred way to serialize JFrame, and others JFoo is the XMLEncoder.

The classic serialization works in some little GUI applications, but not with long life GUI components applications.