actionmenuitem.java

该源代码为一些通用的程序

/* ========================================================================
 * JCommon : a free general purpose class library for the Java(tm) platform
 * ========================================================================
 *
 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
 * 
 * Project Info:  http://www.jfree.org/jcommon/index.html
 *
 * This library is free software; you can redistribute it and/or modify it 
 * under the terms of the GNU Lesser General Public License as published by 
 * the Free Software Foundation; either version 2.1 of the License, or 
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
 * USA.  
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 * 
 * -------------------
 * ActionMenuItem.java
 * -------------------
 * (C)opyright 2002-2004, by Thomas Morgner and Contributors.
 *
 * Original Author:  Thomas Morgner;
 * Contributor(s):   David Gilbert (for Object Refinery Limited);
 *
 * $Id: ActionMenuItem.java,v 1.4 2005/10/18 13:22:12 mungady Exp $
 *
 * ChangeLog
 * ---------
 * 30-Aug-2002 : Initial version
 * 01-Aug-2002 : Documentation
 * 10-Dec-2002 : Minor Javadoc updates (DG);
 *
 */

package org.jfree.ui.action;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.awt.event.KeyEvent;
import javax.swing.Action;
import javax.swing.Icon;
import javax.swing.JMenuItem;
import javax.swing.KeyStroke;

import org.jfree.util.Log;

/**
 * The ActionMenuItem is used to connect an Action and its properties to an
 * MenuItem.
 * <p/>
 * This functionality is already implemented in JDK 1.3 but needed for JDK 1.2.2
 * compatibility.
 *
 * @author Thomas Morgner
 */
public class ActionMenuItem extends JMenuItem
{

  /** The action. */
  private Action action;

  /** The property change handler. */
  private ActionEnablePropertyChangeHandler propertyChangeHandler;

  /**
   * Helperclass to handle the property change event raised by the action.
   * Changed properties in the action will affect the button.
   */
  private class ActionEnablePropertyChangeHandler
          implements PropertyChangeListener
  {
    public ActionEnablePropertyChangeHandler()
    {
    }

    /**
     * Receives notification of a property change event.
     *
     * @param event the property change event.
     */
    public void propertyChange(final PropertyChangeEvent event)
    {
      try
      {
        if (event.getPropertyName().equals("enabled"))
        {
          setEnabled(getAction().isEnabled());
        }
        else if (event.getPropertyName().equals(Action.SMALL_ICON))
        {
          setIcon((Icon) getAction().getValue(Action.SMALL_ICON));
        }
        else if (event.getPropertyName().equals(Action.NAME))
        {
          setText((String) getAction().getValue(Action.NAME));
        }
        else if (event.getPropertyName().equals(Action.SHORT_DESCRIPTION))
        {
          ActionMenuItem.this.setToolTipText((String)
                  getAction().getValue(Action.SHORT_DESCRIPTION));
        }

        final Action ac = getAction();
        if (event.getPropertyName().equals(ActionDowngrade.ACCELERATOR_KEY))
        {
          setAccelerator((KeyStroke) ac.getValue(ActionDowngrade.ACCELERATOR_KEY));
        }
        else if (event.getPropertyName().equals(ActionDowngrade.MNEMONIC_KEY))
        {
          final Object o = ac.getValue(ActionDowngrade.MNEMONIC_KEY);
          if (o != null)
          {
            if (o instanceof Character)
            {
              final Character c = (Character) o;
              setMnemonic(c.charValue());
            }
            else if (o instanceof Integer)
            {
              final Integer c = (Integer) o;
              setMnemonic(c.intValue());
            }
          }
          else
          {
            setMnemonic(KeyEvent.VK_UNDEFINED);
          }
        }
      }
      catch (Exception e)
      {
        Log.warn("Error on PropertyChange in ActionButton: ", e);
      }
    }
  }

  /** Default constructor. */
  public ActionMenuItem()
  {
    // nothing required
  }

  /**
   * Creates a menu item with the specified icon.
   *
   * @param icon the icon.
   */
  public ActionMenuItem(final Icon icon)
  {
    super(icon);
  }

  /**
   * Creates a menu item with the specified label.
   *
   * @param text the label.
   */
  public ActionMenuItem(final String text)
  {
    super(text);
  }

  /**
   * Creates a menu item with the specified label and icon.
   *
   * @param text the label.
   * @param icon the icon.
   */
  public ActionMenuItem(final String text, final Icon icon)
  {
    super(text, icon);
  }

  /**
   * Creates a new menu item with the specified label and mnemonic.
   *
   * @param text the label.
   * @param i    the mnemonic.
   */
  public ActionMenuItem(final String text, final int i)
  {
    super(text, i);
  }

  /**
   * Creates a new menu item based on the specified action.
   *
   * @param action the action.
   */
  public ActionMenuItem(final Action action)
  {
    setAction(action);
  }

  /**
   * Returns the assigned action or null if no action has been assigned.
   *
   * @return the action.
   */
  public Action getAction()
  {
    return this.action;
  }

  /**
   * Returns and initializes the PropertyChangehandler for this ActionMenuItem.
   * The PropertyChangeHandler monitors the action and updates the menuitem if
   * necessary.
   *
   * @return the property change handler.
   */
  private ActionEnablePropertyChangeHandler getPropertyChangeHandler()
  {
    if (this.propertyChangeHandler == null)
    {
      this.propertyChangeHandler = new ActionEnablePropertyChangeHandler();
    }
    return this.propertyChangeHandler;
  }

  /**
   * Enables and disables this button and if an action is assigned to this
   * menuitem the propertychange is forwarded to the assigned action.
   *
   * @param b the new enable-state of this menuitem
   */
  public void setEnabled(final boolean b)
  {
    super.setEnabled(b);
    if (getAction() != null)
    {
      getAction().setEnabled(b);
    }
  }

  /**
   * Assigns the given action to this menuitem. The properties of the action
   * will be assigned to the menuitem. If an previous action was set, the old
   * action is unregistered.
   * <p/>
   * <ul> <li>NAME - specifies the menuitem text <li>SMALL_ICON - specifies the
   * menuitems icon <li>MNEMONIC_KEY - specifies the menuitems mnemonic key
   * <li>ACCELERATOR_KEY - specifies the menuitems accelerator </ul>
   *
   * @param newAction the new action
   */
  public void setAction(final Action newAction)
  {
    final Action oldAction = getAction();
    if (oldAction != null)
    {
      removeActionListener(oldAction);
      oldAction.removePropertyChangeListener(getPropertyChangeHandler());
      setAccelerator(null);
    }
    this.action = newAction;
    if (this.action != null)
    {
      addActionListener(newAction);
      newAction.addPropertyChangeListener(getPropertyChangeHandler());

      setText((String) (newAction.getValue(Action.NAME)));
      setToolTipText((String) (newAction.getValue(Action.SHORT_DESCRIPTION)));
      setIcon((Icon) newAction.getValue(Action.SMALL_ICON));
      setEnabled(this.action.isEnabled());

      Object o = newAction.getValue(ActionDowngrade.MNEMONIC_KEY);
      if (o != null)
      {
        if (o instanceof Character)
        {
          final Character c = (Character) o;
          setMnemonic(c.charValue());
        }
        else if (o instanceof Integer)
        {
          final Integer c = (Integer) o;
          setMnemonic(c.intValue());
        }
      }
      else
      {
        setMnemonic(KeyEvent.VK_UNDEFINED);
      }


      o = newAction.getValue(ActionDowngrade.ACCELERATOR_KEY);
      if (o instanceof KeyStroke)
      {
        setAccelerator((KeyStroke) o);
      }
    }
  }
}