rotatebutton.java

一个用java写的mail.里面的代码值得我们去研究！学习。

/*
** $Id: RotateButton.java,v 1.2 2001/05/07 12:34:45 kunugi Exp $
**
** Copyright (c) 2000-2001 Jeff Gay
** on behalf of ICEMail.org <http://www.icemail.org>
** Copyright (c) 1998-2000 by Timothy Gerard Endres
** 
** This program is free software.
** 
** You may redistribute it and/or modify it under the terms of the GNU
** General Public License as published by the Free Software Foundation.
** Version 2 of the license should be included with this distribution in
** the file LICENSE, as well as License.html. If the license is not
** included with this distribution, you may find a copy at the FSF web
** site at 'www.gnu.org' or 'www.fsf.org', or you may write to the
** Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139 USA.
**
** THIS SOFTWARE IS PROVIDED AS-IS WITHOUT WARRANTY OF ANY KIND,
** NOT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY. THE AUTHOR
** OF THIS SOFTWARE, ASSUMES _NO_ RESPONSIBILITY FOR ANY
** CONSEQUENCE RESULTING FROM THE USE, MODIFICATION, OR
** REDISTRIBUTION OF THIS SOFTWARE.
*/

package org.icemail.util;

import java.awt.Image;
import java.awt.Toolkit;

import java.awt.event.ActionEvent;

import java.lang.IllegalArgumentException;

import java.util.Vector;

import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JButton;


/**
 * RotateButton adds additional functionality to the normal JButton by
 * allowing an application to associate a series of icons and commands to
 * the button.
 * <p>
 * As the button is activated, the icon (shown) and pressed icon (underlying)
 * are rotated, as well as the associated command. This allows the button to
 * be "rotated" through a series of icons and associated commands, providing
 * a multiple state button for applications.
 */
public class RotateButton extends JButton
{
  private Vector entries_ = new Vector( 2 );
  private int    current_ = 0;

  /**
   * Contruct a button.
   * Additional icons must be added to make the button useful, see addIcon().
   * <p>
   * Of course, the JButton methods are also usable.
   */
  public
  RotateButton( )
  {
    super();
  }

  /**
   * Return the current index of the button.
   */
  public int
  current()
  { return current_; }

  /**
   * Add an icon using the given path and associated settings to the button.
   * The path and command are required parameters, whereas the text and tip
   * are optional.
   * <p>
   * Adding icons inconsistantly may producing undesired results, so always
   * provide text and tip when using these optional parameters.
   * <p>
   * The command should reflect the MOVEMENT to the next state, not the current state
   * because the button is going to be pushed, firing an event with the associated
   * command.
   *
   * @param path a path to an icon image
   * @param command associated command which reflects the MOVEMENT to the next state
   * @param text associated text or null
   * @param tip associated tool tip message or null
   */
  public void
  addIcon( String path, String command, String text, String tip )
  {
    if ( path == null || command == null ) {
      throw new IllegalArgumentException( "Invalid argument to RotateButton.addIcon()" );
    }
  // add a new entry
    Image ximage = Toolkit.getDefaultToolkit().getImage( path );
    Entry xentry = new Entry( new ImageIcon( ximage ), command, text, tip );
    entries_.addElement( xentry );

    switch ( entries_.size() ) {
    case 1:
    case 2:
    // rotate special cases to first position
      rotate( 0 );
      break;
    }
  }

  /**
   * A convenience method for applications.
   *
   * @param path a path of an icon image to add to the rotatation list
   * @param command associated command which reflects the MOVEMENT to the next state
   */
  public void
  addIcon( String path, String command )
  {
    addIcon( path, command, null, null );
  }

  /**
   * Add an icon and associated settings to the button.
   * The icon and command are required parameters, whereas the text and tip
   * are optional.
   * <p>
   * Adding icons inconsistantly may producing undesired results, so always
   * provide text and tip when using these optional parameters.
   * <p>
   * The command should reflect the MOVEMENT to the next state, not the current state
   * because the button is going to be pushed, firing an event with the associated
   * command.
   *
   * @param icon an icon to add to the rotatation list
   * @param command associated command which reflects the MOVEMENT to the next state
   * @param text optional associated text
   * @param tip optional associated tool tip message
   */
  public void
  addIcon( Icon icon, String command, String text, String tip )
  {
    if ( icon == null || command == null ) {
      throw new IllegalArgumentException( "Invalid argument to RotateButton.addIcon()" );
    }
  // add a new entry
    Entry xentry = new Entry( icon, command, text, tip );
    entries_.addElement( xentry );

    switch ( entries_.size() ) {
    case 1:
    case 2:
    // rotate special cases to first position
      rotate( 0 );
      break;
    }
  }

  /**
   * A convenience method for applications.
   *
   * @param icon an icon to add to the rotatation list
   * @param command associated command which reflects the MOVEMENT to the next state
   */
  public void
  addIcon( Icon icon, String command )
  {
    addIcon( icon, command, null, null );
  }

  /**
   * Rotate the button to the given position.
   * The routine can be called manually to rotate the button to an initial starting
   * position, however it should be called after adding all icons.
   *
   * @param next index of next rotation
   */
  public void
  rotate( int next )
  {
  // check for error conditions
    int xsize = entries_.size();
    if ( xsize == 0 ) return;
  // set the next position
    current_ = next;
    if ( current_ < 0 || current_ >= xsize ) current_ = 0;
  // set current icon
    Entry xentry = (Entry)entries_.elementAt( current_ );
    setIcon( xentry.icon_ );
  // set current text
    if ( xentry.text_ != null ) {
      setText( xentry.text_ );
    }
  // set current tip
    if ( xentry.tip_ != null ) {
      setToolTipText( xentry.tip_ );
    }
  // set next icon
    if ( ( current_ + 1 ) == xsize ) {
      setPressedIcon( ((Entry)entries_.firstElement()).icon_ );
    }
    else {
      setPressedIcon( ((Entry)entries_.elementAt( current_+1 )).icon_ );
    }
  // set the command
    super.setActionCommand( ((Entry)entries_.elementAt( current_ )).command_  );
  }

  /**
   * This routine is called whenever the button is pushed.
   * Overloaded from javax.swing.AbstractButton.
   * The event is intercepted, the button is rotated automatically, and
   * the event is passed on to listener objects.
   *
   * @param event description
   * @see javax.swing.AbstractButton
   */
  protected void
  fireActionPerformed( ActionEvent event )
  {
    rotate( current_ + 1 );
    super.fireActionPerformed( event );
  }

  /**
   * Internal storage class for icon and command pairs.
   */
  private class Entry
  {
    Icon      icon_;
    String    command_;
    String    text_;
    String    tip_;

    Entry( Icon icon, String command, String text, String tip )
    {
      icon_ = icon;
      command_ = command;
      text_ = text;
      tip_ = tip;
    }

  }
}