/*
    $Id: EscEnterListener.java,v 1.4 2005/03/29 16:26:45 mch Exp $
    */
   
   package org.astrogrid.ui;
   
   import java.awt.Window;
   import java.awt.Component;
   import java.awt.Container;
  import java.awt.Font;
  import java.awt.event.*;
  import javax.swing.JButton;
  
  /***
   * This is an adapter for catching esc & enter keypresses in, eg, a
   * dialog, so that it calls the default button or cancel button.
   * Further catches can be made by subclassing. Also ties windows
   * close button to cancel button.  Should be created and registered
   * after the dialog and its child components have been created and
   * assembled, so that it can add itself ot all the subcomponents.
   * <P>
   * To use, add the following line <B>after</B> the components have been assembled:
   * <pre>
   *    new EscEnterListener(dialog box, default button, cancel button)
   * </pre>
   * It works by registering itself as a keypress listener for all the child
   * components of the dialog box, trapping all [Esc] or [Enter] keypresses.
   * <p>
   * Scope for improvement: If
   * changes are made to the componen tree after constructing the instance as
   * above, keypresses in the new components will not be trapped.  This class
   * could also register itself as a ComponentListener to track such changes if
   * necessary.  At the moment the method RegisterThis(root container) can be
   * used 'manually' to register it with new components.
   *
   * @author M Hill
   */
  /* Change history:
      11/2/2002 - MCH - fix for passing in null default button (don't set font)
      15/2/2002 - MCH - added disposeOnCancel which disposes of window if cancel pressed
   */
  
  public class EscEnterListener extends KeyAdapter
  {
     JButton defaultBtn = null;
     JButton cancelBtn = null;
     Window window = null;
  
     /*** Standard constructor - close presses the cancel button but the window itself
      * must listen out for the button events
      */
     public EscEnterListener(Window aWindow, JButton aDefault, JButton aCancel)
     {
        this(aWindow, aDefault, aCancel, false);
     }
  
     /***
      * Constructor providing a disposeOnCancel argument which will close &
      * dispose the display if cancel (or, therefore, the close icon) is
      * pressed
      */
     public EscEnterListener(Window aWindow, JButton aDefault, JButton aCancel, boolean disposeOnCancel)
     {
        window = aWindow;
        setDefaultBtn(aDefault);
        setCancelBtn(aCancel);
        registerWith(window);
  
        // Add standard window close listener - this presses the cancel button
        // but nothing else (in case cancel fails).
        window.addWindowListener(
              new WindowAdapter()
              {
                 public void windowClosing(WindowEvent e)
                 {
                    if (cancelBtn == null)
                    {
                       //no cancel button, so do standard
                       window.setVisible(false);
                    }
                    else if (cancelBtn.isEnabled())
                    {
                       cancelBtn.doClick();
                    }
                 }
              }
           );
  
        if ((disposeOnCancel) && (cancelBtn != null))
        {
           //add standard dispose-window to cancel button
           cancelBtn.addActionListener(
              new ActionListener()
              {
                 public void actionPerformed(ActionEvent e)
                 {
                    window.hide();
                 }
              }
          );
       }
    }
 
    /*** Sets the button that will close the dialog box when [Esc] is pressed
     */
    public void setCancelBtn(JButton b)
    {
       cancelBtn = b;
    }
 
    /*** Sets the default button. Also sets the button's font to bold
     * to show which one is default.  This button will be activated
     * by the [Enter] key. */
    public void setDefaultBtn(JButton b)
    {
       defaultBtn = b;
       if (defaultBtn != null)
          defaultBtn.setFont(defaultBtn.getFont().deriveFont(Font.BOLD));
    }
 
    /***
     * Registers this listener with all the components in the tree given
     * by comp.  Call this with the root dialog frame and all components
     * will be recursively called down the container tree.  It does not
     * (yet :-) handle later changes to component trees - a subclass could
     * register as a container listener too.. */
    public void registerWith(Component comp)
    {
       //first remove so we don/t get any duplications
       comp.removeKeyListener(this);
 
       //go through all component's children, and add key listener
       comp.addKeyListener(this);
       if (comp instanceof Container)
       {
          Component[] children = ((Container) comp).getComponents();
          for (int i=0;i<children.length;i++)
          {
             registerWith(children[i]);
          }
       }
    }
 
    /*** Check for ESC or ENTER being pressed.  If so, and the relevent
     * button is enabled, click it */
    public void keyPressed(KeyEvent ke)
    {
       if ((ke.getKeyCode() == ke.VK_ENTER) && (defaultBtn != null) && (defaultBtn.isEnabled()))
       {
          defaultBtn.doClick();
       }
       if ((ke.getKeyCode() == ke.VK_ESCAPE) && (cancelBtn != null) && (cancelBtn.isEnabled()))
       {
          cancelBtn.doClick();
       }
       if ((ke.getKeyCode() == ke.VK_ESCAPE) && (cancelBtn == null))
       {
          window.hide();
       }
    }
 
 }
 
 /***
  $Log: EscEnterListener.java,v $
  Revision 1.4  2005/03/29 16:26:45  mch
  Fix in case of null cancel button
 
  Revision 1.3  2004/04/15 16:34:53  mch
  Tidied up, introduced stuff from datacenter ui
 
  Revision 1.1  2004/03/03 17:40:58  mch
  Moved ui package
 
  Revision 1.1  2004/02/17 16:04:06  mch
  New Desktop GUI
 
  Revision 1.1.1.1  2003/08/25 18:36:32  mch
  Reimported to fit It02 source structure
 
  Revision 1.3  2003/07/02 19:15:14  mch
  Removed windows/linux double spacing
 
  */