import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.io.*;
import java.beans.*;

/*
Demo modified from Walrath and Campione's ListDemo.java in
The JFC Swing Tutorial:  Java 2 Platform, Addison Wesley 1999
that has an initially empty list.

This example also demonstrates persistence with XML encoder / decoder
using file "list.xml"

There is probably a simpler way, but I haven't found it.  This version
takes the DefaultListModel and converts to an Object[] and XMLencodes
it.  The complement is to XMLdecode the Object[], add the Objects to a
new DefaultListModel, and set the list's model.

You must first populate the list and then use the XML | Save menu
option to create a file "list.xml" before you can use the menu XML |
Load option to populate an empty list from the persistent store
list.xml.


Mike Barnes
9/16/05
*/

public class XMLListDemo extends JFrame 
                      implements ListSelectionListener {
  public JList list;
  public DefaultListModel listModel;

  private JPanel panel;

  private JButton todoButton, doneButton, editButton;
  private JMenu xmlMenu;
  private JMenuItem load, save;
  private JMenuBar menuBar;
  private JTextField textValue;

  public XMLListDemo() {
    super("XML List Demo");
    listModel = new DefaultListModel();

    //Create the list and put it in a scroll pane
    list = new JList(listModel);
    list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    list.addListSelectionListener(this);
    JScrollPane listScrollPane = new JScrollPane(list);

    todoButton = new JButton("To do");
    todoButton.addActionListener(new ToDoListener());

    doneButton = new JButton("Done");
    doneButton.setEnabled(false);
    doneButton.addActionListener(new DoneListener());

    editButton = new JButton("Edit");
    editButton.setEnabled(false);
    editButton.addActionListener(new EditListener());


    // menu
    xmlMenu = new JMenu("XML");
    save = new JMenuItem("Save");
    save.addActionListener(new XMLSaveListener());
    load = new JMenuItem("Load");
    load.addActionListener(new XMLLoadListener());
    menuBar = new JMenuBar();
    xmlMenu.add(load);
    xmlMenu.add(save);
    menuBar.add(xmlMenu);
    setJMenuBar(menuBar);
    
    textValue = new JTextField(10);
    textValue.addActionListener(new ToDoListener());
    textValue.setText("");

    //Create a panel that uses FlowLayout (the default).
    JPanel buttonPane = new JPanel();
    buttonPane.add(textValue);
    buttonPane.add(todoButton);
    buttonPane.add(doneButton);
    buttonPane.add(editButton);

    Container contentPane = getContentPane();
    contentPane.setLayout(new BorderLayout());
    listScrollPane.setPreferredSize(new Dimension(300, 200));
    contentPane.add(listScrollPane, BorderLayout.CENTER);
    contentPane.add(buttonPane, BorderLayout.SOUTH);
    System.out.println("selected position is" +
      Integer.toString(list.getSelectedIndex()));
    }

  class XMLLoadListener implements ActionListener {
    public void actionPerformed (ActionEvent e) {
      XMLDecoder fin = null;
      Object[] elements;
      try {
        fin = new XMLDecoder (
              new BufferedInputStream (new FileInputStream("list.xml")));
        elements = (Object[]) fin.readObject();
        listModel = new DefaultListModel();
        for(int i = 0; i < elements.length; i++)  
          listModel.addElement(elements[i]);
        list.setModel(listModel);
        }
      catch (FileNotFoundException fnfe) {} 
      fin.close();
      System.out.println("XMLDecoder"); 
      }
    }

  class XMLSaveListener implements ActionListener {
    public void actionPerformed (ActionEvent e) {
      XMLEncoder fout = null;
      Object[] elements;
      try {
        fout = new XMLEncoder (
                new BufferedOutputStream (new FileOutputStream("list.xml")));
        elements = new Object[list.getModel().getSize()];
        elements = ((DefaultListModel) list.getModel()).toArray();
        fout.writeObject(elements);
        }
      catch (FileNotFoundException fnfe) {} 
      fout.close();
      System.out.println("XMLEncoder"); }
    }

  class EditListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      int index = list.getSelectedIndex();
      listModel.insertElementAt(textValue.getText(), index);
      listModel.remove(index +1);
      list.setSelectedIndex(index);
      }
    }

  class DoneListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      //This method can be called only if
      //there's a valid selection
      //so go ahead and remove whatever's selected.
      int index = list.getSelectedIndex();
      System.out.println("remove position is" +
      Integer.toString(list.getSelectedIndex()));
      listModel.remove(index);

      int size = listModel.getSize();

      if (size == 0) {
          //Nobody's left, disable firing.
          doneButton.setEnabled(false);
          editButton.setEnabled(false); } 
        else {
          //Adjust the selection.
          if (index == listModel.getSize())//removed item in last position
          index--;
         list.setSelectedIndex(index); }   //otherwise select same index
        }
    }

  //This listener is shared by the text field and the ToDo button
  class ToDoListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      //User didn't type in a name...
      if (textValue.getText().equals("")) {
        Toolkit.getDefaultToolkit().beep();
        return;
        }

      int index = list.getSelectedIndex();
      int size = listModel.getSize();

      //If no selection or if item in last position is selected,
      //add the new hire to end of list, and select new hire.
      if (index == -1 || (index+1 == size)) {
          listModel.addElement(textValue.getText());
          list.setSelectedIndex(size); }
        //Otherwise insert the new hire after the current selection,
        //and select new hire.
        else {
          listModel.insertElementAt(textValue.getText(), index+1);
          list.setSelectedIndex(index+1);
          }
      System.out.println("added position is" +
         Integer.toString(list.getSelectedIndex()));
      }
    }

  public void valueChanged(ListSelectionEvent e) {
    if (e.getValueIsAdjusting() == false) {
      if (list.getSelectedIndex() == -1) {
          //No selection, disable fire button.
          doneButton.setEnabled(false);
          editButton.setEnabled(false);
          textValue.setText(""); } 
        else {
          //Selection, update text field.
          editButton.setEnabled(true);
          doneButton.setEnabled(true);
          String name = list.getSelectedValue().toString();
          textValue.setText(name); }
        }
    }

  public static void main(String s[]) {
    JFrame frame = new XMLListDemo();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.pack();
    frame.setVisible(true);
    }
    }