menucomponent.java

gcc的组建

/* MenuComponent.java -- Superclass of all AWT menu components
   Copyright (C) 1999, 2000, 2002, 2003, 2004, 2005  Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath 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
General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */


package java.awt;

import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.awt.peer.MenuComponentPeer;
import java.io.Serializable;
import java.util.Locale;

import javax.accessibility.Accessible;
import javax.accessibility.AccessibleComponent;
import javax.accessibility.AccessibleContext;
import javax.accessibility.AccessibleRole;
import javax.accessibility.AccessibleSelection;
import javax.accessibility.AccessibleStateSet;

/**
  * This is the superclass of all menu AWT widgets. 
  *
  * @author Aaron M. Renn ([e-mail])
  * @author Andrew John Hughes ([e-mail])
  */
public abstract class MenuComponent implements Serializable
{

/*
 * Static Variables
 */

// Serialization Constant
private static final long serialVersionUID = -4536902356223894379L;

/*************************************************************************/
  
/*
 * Instance Variables
 */

/**
 * The font for this component.
 *
 * @see #getFont()
 * @see #setFont(java.awt.Font)
 * @serial the component's font.
 */
  private Font font;

  /**
   * The name of the component.
   *
   * @see #getName()
   * @see #setName(String)
   * @serial the component's name.
   */
  private String name;

  /**
   * The parent of this component.
   *
   * @see #getParent()
   * @see #setParent(java.awt.MenuContainer)
   * @serial ignored.
   */
  transient MenuContainer parent;

  /**
   * The native peer for this component.
   *
   * @see #getPeer()
   * @see #setPeer(java.awt.peer.MenuComponentPeer)
   * @serial ignored.
   */
  transient MenuComponentPeer peer;

  /**
   * The synchronization locking object for this component.
   *
   * @serial ignored.
   */
  private transient Object tree_lock = this;

  /**
   * The toolkit for this object.
   *
   * @see #getToolkit()
   * @serial ignored.
   */
  private static transient Toolkit toolkit = Toolkit.getDefaultToolkit();

  /**
   * The accessible context for this component.
   *
   * @see #getAccessibleContext()
   * @serial the accessibility information for this component.
   */
  AccessibleContext accessibleContext;

  /**
   * Was the name of the component set?  This value defaults
   * to false and becomes true after a call to <code>setName()</code>.
   * Please note that this does not guarantee that name will then
   * be non-null, as this may be the value passed to <code>setName()</code>.
   *
   * @see #setName(String)
   * @serial true if the name value has been explicitly set by calling
   *         <code>setName()</code>.
   */
  private boolean nameExplicitlySet;

  /**
   * Does this component handle new events?  Events will be handled
   * by this component if this is true.  Otherwise, they will be forwarded
   * up the component hierarchy.  This implementation does not use this
   * variable; it is merely provided for serialization compatability.
   *
   * @see #dispatchEvent(AWTEvent)
   * @serial true if events are to be processed locally.  Unused.
   */
  private boolean newEventsOnly;

  /**
   * The focus listener chain handler which deals with focus events for
   * the accessible context of this component.
   *
   * @see AccessibleAWTMenuComponent#addFocusListener(java.awt.event.FocusListener)
   * @serial ignored.
   * This is package-private to avoid an accessor method.
   */
  transient FocusListener focusListener;

/*************************************************************************/

/*
 * Constructors
 */

/**
  * Default constructor for subclasses.
  *
  * @exception HeadlessException If GraphicsEnvironment.isHeadless() is true.
  */
public
MenuComponent()
{
  if (GraphicsEnvironment.isHeadless())
    throw new HeadlessException ();
}

/*************************************************************************/

/*
 * Instance Methods
 */

/**
  * Returns the font in use for this component.
  *
  * @return The font for this component.
  */
public Font
getFont()
{
  if (font != null)
    return font;

  if (parent != null)
    return parent.getFont ();

  return null;
}

/*************************************************************************/

/**
  * Sets the font for this component to the specified font.
  *
  * @param font The new font for this component.
  */
public void
setFont(Font font)
{
  this.font = font;
}

/*************************************************************************/

/**
  * Returns the name of this component.
  *
  * @return The name of this component.
  */
public String
getName()
{
  return(name);
}

/*************************************************************************/

/**
  * Sets the name of this component to the specified name.
  *
  * @param name The new name of this component.
  */
public void
setName(String name)
{
  this.name = name;
  nameExplicitlySet = true;
}

/*************************************************************************/

/**
  * Returns the parent of this component.
  * 
  * @return The parent of this component.
  */
public MenuContainer
getParent()
{
  return(parent);
} 

/*************************************************************************/

// Sets the parent of this component.
final void
setParent(MenuContainer parent)
{
  this.parent = parent;
}

/*************************************************************************/

/**
  * Returns the native windowing system peer for this component.
  *
  * @return The peer for this component.
  *
  * @deprecated
  */
public MenuComponentPeer
getPeer()
{
  return(peer);
}

/*************************************************************************/

// Sets the peer for this component.
final void
setPeer(MenuComponentPeer peer)
{
  this.peer = peer;
}

/*************************************************************************/

/**
  * Destroys this component's native peer
  */
public void
removeNotify()
{
  if (peer != null)
    peer.dispose();
  peer = null;
}

/*************************************************************************/

/**
  * Returns the toolkit in use for this component.
  *
  * @return The toolkit for this component.
  */
final Toolkit
getToolkit()
{
  return(toolkit);
}

/*************************************************************************/

/**
  * Returns the object used for synchronization locks on this component
  * when performing tree and layout functions.
  *
  * @return The synchronization lock for this component.
  */
protected final Object
getTreeLock()
{
  return(tree_lock);
}

/*************************************************************************/

// The sync lock object for this component.
final void
setTreeLock(Object tree_lock)
{
  this.tree_lock = tree_lock;
}

/*************************************************************************/

/**
  * AWT 1.0 event dispatcher.
  *
  * @deprecated Deprecated in favor of <code>dispatchEvent()</code>.
  * @return true if the event was dispatched, false otherwise.
  */
public boolean
postEvent(Event event)
{
  // This is overridden by subclasses that support events.
  return false;
}
/*************************************************************************/

/**
  * Sends this event to this component or a subcomponent for processing.
  *
  * @param event The event to dispatch
  */
public final void dispatchEvent(AWTEvent event)
{
  // See comment in Component.dispatchEvent().
  dispatchEventImpl(event);
}


/**
 * Implementation of dispatchEvent. Allows trusted package classes
 * to dispatch additional events first.  This implementation first
 * translates <code>event</code> to an AWT 1.0 event and sends the
 * result to {@link #postEvent}.  The event is then
 * passed on to {@link #processEvent} for local processing.
 *
 * @param event the event to dispatch.
 */
void dispatchEventImpl(AWTEvent event)
{
  Event oldStyleEvent;

  // This is overridden by subclasses that support events.
  /* Convert AWT 1.1 event to AWT 1.0 event */
  oldStyleEvent = Component.translateEvent(event);
  if (oldStyleEvent != null)
    {
      postEvent(oldStyleEvent);
    }
  /* Do local processing */
  processEvent(event);
}

/*************************************************************************/

/**
  * Processes the specified event.  In this class, this method simply
  * calls one of the more specific event handlers.
  * 
  * @param event The event to process.
  */
protected void
processEvent(AWTEvent event)
{
  /* 
     Pass a focus event to the focus listener for
     the accessibility context.
  */
  if (event instanceof FocusEvent)
    {
      if (focusListener != null)
        {
          switch (event.id)
            {
            case FocusEvent.FOCUS_GAINED:
              focusListener.focusGained((FocusEvent) event);
              break;
            case FocusEvent.FOCUS_LOST:
              focusListener.focusLost((FocusEvent) event);
              break;
            }
        }
    }
}

/*************************************************************************/

/**
  * Returns a string representation of this component.
  *
  * @return A string representation of this component
  */
public String
toString()
{
  return this.getClass().getName() + "[" + paramString() + "]";
}

/*************************************************************************/