gcc/libjava/classpath/javax/swing/KeyboardManager.java

/* KeyboardManager.java -- 
   Copyright (C) 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.

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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
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permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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package javax.swing;

import java.applet.Applet;
import java.awt.Component;
import java.awt.Container;
import java.awt.Window;
import java.awt.event.KeyEvent;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;
import java.util.WeakHashMap;

/**
 * This class maintains a mapping from top-level containers to a 
 * Hashtable.  The Hashtable maps KeyStrokes to Components to be used when 
 * Components register keyboard actions with the condition
 * JComponent.WHEN_IN_FOCUSED_WINDOW.
 * 
 * @author Anthony Balkissoon abalkiss at redhat dot com
 *
 */
class KeyboardManager
{
  /** Shared instance of KeyboardManager **/
  static KeyboardManager manager = new KeyboardManager();
  
  /** 
   * A mapping between top level containers and Hashtables that 
   * map KeyStrokes to Components.
   */
  WeakHashMap topLevelLookup = new WeakHashMap();  
  
  /**
   * A mapping between top level containers and Vectors of JMenuBars
   * used to allow all the JMenuBars within a top level container
   * a chance to consume key events.
   */
  Hashtable menuBarLookup = new Hashtable();
  /**
   * Returns the shared instance of KeyboardManager.
   * @return the shared instance of KeybaordManager.
   */
  public static KeyboardManager getManager()
  {
    return manager;
  }
  /**
   * Returns the top-level ancestor for the given JComponent.
   * @param c the JComponent whose top-level ancestor we want
   * @return the top-level ancestor for the given JComponent.
   */
  static Container findTopLevel (Component c)
  {
    Container topLevel = (c instanceof Container) ? (Container) c
                                                 : c.getParent();
    while (topLevel != null && 
           !(topLevel instanceof Window) && 
           !(topLevel instanceof Applet) && 
           !(topLevel instanceof JInternalFrame))
      topLevel = topLevel.getParent();
    return topLevel;
  }
  
  /**
   * Returns the Hashtable that maps KeyStrokes to Components, for 
   * the specified top-level container c.  If no Hashtable exists
   * we create and register it here and return the newly created
   * Hashtable.
   * 
   * @param c the top-level container whose Hashtable we want
   * @return the Hashtable mapping KeyStrokes to Components for the 
   * specified top-level container
   */
  Hashtable getHashtableForTopLevel (Container c)
  {
    Hashtable keyToComponent = (Hashtable)topLevelLookup.get(c);
    if (keyToComponent == null)
      {
        keyToComponent = new Hashtable();
        topLevelLookup.put(c, keyToComponent);
      }
    return keyToComponent;
  }
  
  /**
   * Registers a KeyStroke with a Component.  This does not register
   * the KeyStroke to a specific Action.  When searching for a 
   * WHEN_IN_FOCUSED_WINDOW binding we will first go up to the focused
   * top-level Container, then get the Hashtable that maps KeyStrokes 
   * to components for that particular top-level Container, then 
   * call processKeyBindings on that component with the condition
   * JComponent.WHEN_IN_FOCUSED_WINDOW.
   * @param comp the JComponent associated with the KeyStroke
   * @param key the KeyStroke
   */
  public void registerBinding(JComponent comp, KeyStroke key)
  {
    // This method associates a KeyStroke with a particular JComponent
    // When the KeyStroke occurs, if this component's top-level ancestor
    // has focus (one of its children is the focused Component) then 
    // comp.processKeyBindings will be called with condition
    // JComponent.WHEN_IN_FOCUSED_WINDOW.

    // Look for the JComponent's top-level parent and return if it is null
    Container topLevel = findTopLevel(comp);
    if (topLevel == null)
      return;
    
    // Now get the Hashtable for this top-level container
    Hashtable keyToComponent = getHashtableForTopLevel(topLevel);    
    
    // And add the new binding to this Hashtable
    // FIXME: should allow more than one JComponent to be associated
    // with a KeyStroke, in case one of them is disabled
    keyToComponent.put(key, comp);
  }
  
  public void clearBindingsForComp(JComponent comp)
  {
    // This method clears all the WHEN_IN_FOCUSED_WINDOW bindings associated
    // with <code>comp</code>.  This is used for a terribly ineffcient
    // strategy in which JComponent.updateComponentInputMap simply clears
    // all bindings associated with its component and then reloads all the
    // bindings from the updated ComponentInputMap.  This is only a preliminary
    // strategy and should be improved upon once the WHEN_IN_FOCUSED_WINDOW
    // bindings work.
    
    // Find the top-level ancestor
    
    Container topLevel = findTopLevel(comp);
    if (topLevel == null)
      return;
    // And now get its Hashtable
    Hashtable keyToComponent = getHashtableForTopLevel(topLevel);

    Enumeration keys = keyToComponent.keys();
    Object temp;

    // Iterate through the keys and remove any key whose value is comp
    while (keys.hasMoreElements())
      {
        temp = keys.nextElement();
        if (comp == (JComponent)keyToComponent.get(temp))
          keyToComponent.remove(temp);          
      }
  }
    
  /**
   * This method registers all the bindings in the given ComponentInputMap.
   * Rather than call registerBinding on all the keys, we do the work here
   * so that we don't duplicate finding the top-level container and 
   * getting its Hashtable.
   * 
   * @param map the ComponentInputMap whose bindings we want to register
   */
  public void registerEntireMap (ComponentInputMap map)
  {
    if (map == null)
      return;    
    JComponent comp = map.getComponent();
    KeyStroke[] keys = map.allKeys();
    if (keys == null)
      return;
    // Find the top-level container associated with this ComponentInputMap
    Container topLevel = findTopLevel(comp);
    if (topLevel == null)
      return;
    
    // Register the KeyStrokes in the top-level container's Hashtable
    Hashtable keyToComponent = getHashtableForTopLevel(topLevel);
    for (int i = 0; i < keys.length; i++)
      keyToComponent.put(keys[i], comp);
  }
  
  public boolean processKeyStroke (Component comp, KeyStroke key, KeyEvent e)
  {
    boolean pressed = e.getID() == KeyEvent.KEY_PRESSED;

    // Look for the top-level ancestor
    Container topLevel = findTopLevel(comp);
    if (topLevel == null)
      return false;    
    // Now get the Hashtable for that top-level container
    Hashtable keyToComponent = getHashtableForTopLevel(topLevel);
    Enumeration keys = keyToComponent.keys();
    JComponent target = (JComponent)keyToComponent.get(key);    
    if (target != null && target.processKeyBinding
        (key, e, JComponent.WHEN_IN_FOCUSED_WINDOW, pressed))
      return true;
    
    // Have to give all the JMenuBars a chance to consume the event
    Vector menuBars = getVectorForTopLevel(topLevel);
    for (int i = 0; i < menuBars.size(); i++)
      if (((JMenuBar)menuBars.elementAt(i)).processKeyBinding(key, e, JComponent.WHEN_IN_FOCUSED_WINDOW, pressed))
        return true;
    return false;
  }
  
  /**
   * Returns the Vector of JMenuBars associated with the top-level
   * @param c the top-level container whose JMenuBar Vector we want
   * @return the Vector of JMenuBars for this top level container
   */
  Vector getVectorForTopLevel(Container c)
  {
    Vector result = (Vector) menuBarLookup.get(c);
    if (result == null)
      {
        result = new Vector();
        menuBarLookup.put (c, result);
      }
    return result;
  }
  
  /**
   * In processKeyStroke, KeyManager must give all JMenuBars in the 
   * focused top-level container a chance to process the event.  So, 
   * JMenuBars must be registered in KeyManager and associated with a 
   * top-level container.  That's what this method is for.
   * @param menuBar the JMenuBar to register
   */
  public void registerJMenuBar (JMenuBar menuBar)
  {
    Container topLevel = findTopLevel(menuBar);
    Vector menuBars = getVectorForTopLevel(topLevel);
    if (!menuBars.contains(menuBar))
      menuBars.add(menuBar);
  }
  
  /**
   * Unregisters a JMenuBar from its top-level container.  This is 
   * called before the JMenuBar is actually removed from the container
   * so findTopLevel will still find us the correct top-level container.
   * @param menuBar the JMenuBar to unregister.
   */
  public void unregisterJMenuBar (JMenuBar menuBar)
  {
    Container topLevel = findTopLevel(menuBar);
    Vector menuBars = getVectorForTopLevel(topLevel);
    if (menuBars.contains(menuBar))
      menuBars.remove(menuBar);
  }
}