// ActionExample.java
// An application that shows the Action class in, well, action.
//

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

public class ActionExample extends JFrame {

  public static final int MIN_CHANNEL = 2;
  public static final int MAX_CHANNEL = 13;

  private int currentChannel = MIN_CHANNEL;
  private int favoriteChannel = 9;
  private JLabel channelLabel = new JLabel();

  private Action upAction = new UpAction();
  private Action downAction = new DownAction();
  private GotoFavoriteAction gotoFavoriteAction = new GotoFavoriteAction();
  private Action setFavoriteAction = new SetFavoriteAction();

  public class UpAction extends AbstractAction {
    public UpAction() {
      putValue(NAME, "Channel Up");
      putValue(SMALL_ICON, new ImageIcon("images/up.gif"));
      putValue(SHORT_DESCRIPTION, "Increment the channel number");
      putValue(MNEMONIC_KEY, new Integer(KeyEvent.VK_U));
    }
    public void actionPerformed(ActionEvent ae) {
      setChannel(currentChannel+1);
    }
  }

  public class DownAction extends AbstractAction {
    public DownAction() {
      putValue(NAME, "Channel Down");
      putValue(SMALL_ICON, new ImageIcon("images/down.gif"));
      putValue(SHORT_DESCRIPTION, "Decrement the channel number");
      putValue(MNEMONIC_KEY, new Integer(KeyEvent.VK_D));
    }
    public void actionPerformed(ActionEvent ae) {
      setChannel(currentChannel-1);
    }
  }

  public class GotoFavoriteAction extends AbstractAction {
    public GotoFavoriteAction() {
      putValue(SMALL_ICON, new ImageIcon("images/fav.gif"));
      putValue(MNEMONIC_KEY, new Integer(KeyEvent.VK_G));
      updateProperties();
    }
    public void updateProperties() {
      putValue(NAME, "Go to channel "+favoriteChannel);
      putValue(SHORT_DESCRIPTION, "Change the channel to "+favoriteChannel);
    }
    public void actionPerformed(ActionEvent ae) {
      setChannel(favoriteChannel);
    }
  }

  public class SetFavoriteAction extends AbstractAction {
    public SetFavoriteAction() {
      putValue(NAME, "Set 'Go to' channel");
      putValue(SMALL_ICON, new ImageIcon("images/set.gif"));
      putValue(SHORT_DESCRIPTION,
               "Make current channel the Favorite channel");
      putValue(MNEMONIC_KEY, new Integer(KeyEvent.VK_S));
    }
    public void actionPerformed(ActionEvent ae) {
      favoriteChannel = currentChannel;
      gotoFavoriteAction.updateProperties();
      setEnabled(false);
      gotoFavoriteAction.setEnabled(false);
    }
  }

  public ActionExample() {
    super("ActionExample");  
  
    setChannel(currentChannel); // enable/disable the Actions as appropriate

    channelLabel.setHorizontalAlignment(JLabel.CENTER);
    channelLabel.setFont(new Font("Serif", Font.PLAIN, 32));

    getContentPane().add(channelLabel, BorderLayout.NORTH);

    JPanel buttonPanel = new JPanel(new GridLayout(2, 2, 16, 6));
    buttonPanel.setBorder(BorderFactory.createEmptyBorder(6, 16, 16, 16));
    getContentPane().add(buttonPanel, BorderLayout.CENTER);
    buttonPanel.add(new JButton(upAction));
    buttonPanel.add(new JButton(gotoFavoriteAction));
    buttonPanel.add(new JButton(downAction));
    buttonPanel.add(new JButton(setFavoriteAction));

    JMenuBar mb = new JMenuBar();
    JMenu menu = new JMenu("Channel");
    menu.add(new JMenuItem(upAction));
    menu.add(new JMenuItem(downAction));
    menu.addSeparator();
    menu.add(new JMenuItem(gotoFavoriteAction));
    menu.add(new JMenuItem(setFavoriteAction));
    mb.add(menu);
    setJMenuBar(mb);
  }

  public void setChannel(int chan) {
    currentChannel = chan;
    channelLabel.setText("Now tuned to channel: "+currentChannel);
    // enable/disable the Actions as appropriate
    downAction.setEnabled(currentChannel > MIN_CHANNEL);
    upAction.setEnabled(currentChannel < MAX_CHANNEL);
    gotoFavoriteAction.setEnabled(currentChannel != favoriteChannel);  
    setFavoriteAction.setEnabled(currentChannel != favoriteChannel);  
  }

  public static void main(String argv[]) {
    JFrame f = new ActionExample();
    f.setSize(400, 180);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.setVisible(true);
  }
}