src/java.desktop/share/classes/java/awt/AWTEventMulticaster.java
changeset 47216 71c04702a3d5
parent 35667 ed476aba94de
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.desktop/share/classes/java/awt/AWTEventMulticaster.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,1121 @@
+/*
+ * Copyright (c) 1996, 2015, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code 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
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package java.awt;
+
+import java.awt.event.*;
+import java.lang.reflect.Array;
+import java.util.EventListener;
+import java.io.Serializable;
+import java.io.ObjectOutputStream;
+import java.io.IOException;
+import java.util.EventListener;
+
+
+/**
+ * {@code AWTEventMulticaster} implements efficient and thread-safe multi-cast
+ * event dispatching for the AWT events defined in the {@code java.awt.event}
+ * package.
+ * <p>
+ * The following example illustrates how to use this class:
+ *
+ * <pre><code>
+ * public myComponent extends Component {
+ *     ActionListener actionListener = null;
+ *
+ *     public synchronized void addActionListener(ActionListener l) {
+ *         actionListener = AWTEventMulticaster.add(actionListener, l);
+ *     }
+ *     public synchronized void removeActionListener(ActionListener l) {
+ *         actionListener = AWTEventMulticaster.remove(actionListener, l);
+ *     }
+ *     public void processEvent(AWTEvent e) {
+ *         // when event occurs which causes "action" semantic
+ *         ActionListener listener = actionListener;
+ *         if (listener != null) {
+ *             listener.actionPerformed(new ActionEvent());
+ *         }
+ *     }
+ * }
+ * </code></pre>
+ * The important point to note is the first argument to the {@code
+ * add} and {@code remove} methods is the field maintaining the
+ * listeners. In addition you must assign the result of the {@code add}
+ * and {@code remove} methods to the field maintaining the listeners.
+ * <p>
+ * {@code AWTEventMulticaster} is implemented as a pair of {@code
+ * EventListeners} that are set at construction time. {@code
+ * AWTEventMulticaster} is immutable. The {@code add} and {@code
+ * remove} methods do not alter {@code AWTEventMulticaster} in
+ * anyway. If necessary, a new {@code AWTEventMulticaster} is
+ * created. In this way it is safe to add and remove listeners during
+ * the process of an event dispatching.  However, event listeners
+ * added during the process of an event dispatch operation are not
+ * notified of the event currently being dispatched.
+ * <p>
+ * All of the {@code add} methods allow {@code null} arguments. If the
+ * first argument is {@code null}, the second argument is returned. If
+ * the first argument is not {@code null} and the second argument is
+ * {@code null}, the first argument is returned. If both arguments are
+ * {@code non-null}, a new {@code AWTEventMulticaster} is created using
+ * the two arguments and returned.
+ * <p>
+ * For the {@code remove} methods that take two arguments, the following is
+ * returned:
+ * <ul>
+ *   <li>{@code null}, if the first argument is {@code null}, or
+ *       the arguments are equal, by way of {@code ==}.
+ *   <li>the first argument, if the first argument is not an instance of
+ *       {@code AWTEventMulticaster}.
+ *   <li>result of invoking {@code remove(EventListener)} on the
+ *       first argument, supplying the second argument to the
+ *       {@code remove(EventListener)} method.
+ * </ul>
+ * <p>Swing makes use of
+ * {@link javax.swing.event.EventListenerList EventListenerList} for
+ * similar logic. Refer to it for details.
+ *
+ * @see javax.swing.event.EventListenerList
+ *
+ * @author      John Rose
+ * @author      Amy Fowler
+ * @since       1.1
+ */
+
+public class AWTEventMulticaster implements
+    ComponentListener, ContainerListener, FocusListener, KeyListener,
+    MouseListener, MouseMotionListener, WindowListener, WindowFocusListener,
+    WindowStateListener, ActionListener, ItemListener, AdjustmentListener,
+    TextListener, InputMethodListener, HierarchyListener,
+    HierarchyBoundsListener, MouseWheelListener {
+
+    /**
+     * A variable in the event chain (listener-a)
+     */
+    protected final EventListener a;
+
+    /**
+     * A variable in the event chain (listener-b)
+     */
+    protected final EventListener b;
+
+    /**
+     * Creates an event multicaster instance which chains listener-a
+     * with listener-b. Input parameters {@code a} and {@code b}
+     * should not be {@code null}, though implementations may vary in
+     * choosing whether or not to throw {@code NullPointerException}
+     * in that case.
+     * @param a listener-a
+     * @param b listener-b
+     */
+    protected AWTEventMulticaster(EventListener a, EventListener b) {
+        this.a = a; this.b = b;
+    }
+
+    /**
+     * Removes a listener from this multicaster.
+     * <p>
+     * The returned multicaster contains all the listeners in this
+     * multicaster with the exception of all occurrences of {@code oldl}.
+     * If the resulting multicaster contains only one regular listener
+     * the regular listener may be returned.  If the resulting multicaster
+     * is empty, then {@code null} may be returned instead.
+     * <p>
+     * No exception is thrown if {@code oldl} is {@code null}.
+     *
+     * @param oldl the listener to be removed
+     * @return resulting listener
+     */
+    protected EventListener remove(EventListener oldl) {
+        if (oldl == a)  return b;
+        if (oldl == b)  return a;
+        EventListener a2 = removeInternal(a, oldl);
+        EventListener b2 = removeInternal(b, oldl);
+        if (a2 == a && b2 == b) {
+            return this;        // it's not here
+        }
+        return addInternal(a2, b2);
+    }
+
+    /**
+     * Handles the componentResized event by invoking the
+     * componentResized methods on listener-a and listener-b.
+     * @param e the component event
+     */
+    public void componentResized(ComponentEvent e) {
+        ((ComponentListener)a).componentResized(e);
+        ((ComponentListener)b).componentResized(e);
+    }
+
+    /**
+     * Handles the componentMoved event by invoking the
+     * componentMoved methods on listener-a and listener-b.
+     * @param e the component event
+     */
+    public void componentMoved(ComponentEvent e) {
+        ((ComponentListener)a).componentMoved(e);
+        ((ComponentListener)b).componentMoved(e);
+    }
+
+    /**
+     * Handles the componentShown event by invoking the
+     * componentShown methods on listener-a and listener-b.
+     * @param e the component event
+     */
+    public void componentShown(ComponentEvent e) {
+        ((ComponentListener)a).componentShown(e);
+        ((ComponentListener)b).componentShown(e);
+    }
+
+    /**
+     * Handles the componentHidden event by invoking the
+     * componentHidden methods on listener-a and listener-b.
+     * @param e the component event
+     */
+    public void componentHidden(ComponentEvent e) {
+        ((ComponentListener)a).componentHidden(e);
+        ((ComponentListener)b).componentHidden(e);
+    }
+
+    /**
+     * Handles the componentAdded container event by invoking the
+     * componentAdded methods on listener-a and listener-b.
+     * @param e the component event
+     */
+    public void componentAdded(ContainerEvent e) {
+        ((ContainerListener)a).componentAdded(e);
+        ((ContainerListener)b).componentAdded(e);
+    }
+
+    /**
+     * Handles the componentRemoved container event by invoking the
+     * componentRemoved methods on listener-a and listener-b.
+     * @param e the component event
+     */
+    public void componentRemoved(ContainerEvent e) {
+        ((ContainerListener)a).componentRemoved(e);
+        ((ContainerListener)b).componentRemoved(e);
+    }
+
+    /**
+     * Handles the focusGained event by invoking the
+     * focusGained methods on listener-a and listener-b.
+     * @param e the focus event
+     */
+    public void focusGained(FocusEvent e) {
+        ((FocusListener)a).focusGained(e);
+        ((FocusListener)b).focusGained(e);
+    }
+
+    /**
+     * Handles the focusLost event by invoking the
+     * focusLost methods on listener-a and listener-b.
+     * @param e the focus event
+     */
+    public void focusLost(FocusEvent e) {
+        ((FocusListener)a).focusLost(e);
+        ((FocusListener)b).focusLost(e);
+    }
+
+    /**
+     * Handles the keyTyped event by invoking the
+     * keyTyped methods on listener-a and listener-b.
+     * @param e the key event
+     */
+    public void keyTyped(KeyEvent e) {
+        ((KeyListener)a).keyTyped(e);
+        ((KeyListener)b).keyTyped(e);
+    }
+
+    /**
+     * Handles the keyPressed event by invoking the
+     * keyPressed methods on listener-a and listener-b.
+     * @param e the key event
+     */
+    public void keyPressed(KeyEvent e) {
+        ((KeyListener)a).keyPressed(e);
+        ((KeyListener)b).keyPressed(e);
+    }
+
+    /**
+     * Handles the keyReleased event by invoking the
+     * keyReleased methods on listener-a and listener-b.
+     * @param e the key event
+     */
+    public void keyReleased(KeyEvent e) {
+        ((KeyListener)a).keyReleased(e);
+        ((KeyListener)b).keyReleased(e);
+    }
+
+    /**
+     * Handles the mouseClicked event by invoking the
+     * mouseClicked methods on listener-a and listener-b.
+     * @param e the mouse event
+     */
+    public void mouseClicked(MouseEvent e) {
+        ((MouseListener)a).mouseClicked(e);
+        ((MouseListener)b).mouseClicked(e);
+    }
+
+    /**
+     * Handles the mousePressed event by invoking the
+     * mousePressed methods on listener-a and listener-b.
+     * @param e the mouse event
+     */
+    public void mousePressed(MouseEvent e) {
+        ((MouseListener)a).mousePressed(e);
+        ((MouseListener)b).mousePressed(e);
+    }
+
+    /**
+     * Handles the mouseReleased event by invoking the
+     * mouseReleased methods on listener-a and listener-b.
+     * @param e the mouse event
+     */
+    public void mouseReleased(MouseEvent e) {
+        ((MouseListener)a).mouseReleased(e);
+        ((MouseListener)b).mouseReleased(e);
+    }
+
+    /**
+     * Handles the mouseEntered event by invoking the
+     * mouseEntered methods on listener-a and listener-b.
+     * @param e the mouse event
+     */
+    public void mouseEntered(MouseEvent e) {
+        ((MouseListener)a).mouseEntered(e);
+        ((MouseListener)b).mouseEntered(e);
+    }
+
+    /**
+     * Handles the mouseExited event by invoking the
+     * mouseExited methods on listener-a and listener-b.
+     * @param e the mouse event
+     */
+    public void mouseExited(MouseEvent e) {
+        ((MouseListener)a).mouseExited(e);
+        ((MouseListener)b).mouseExited(e);
+    }
+
+    /**
+     * Handles the mouseDragged event by invoking the
+     * mouseDragged methods on listener-a and listener-b.
+     * @param e the mouse event
+     */
+    public void mouseDragged(MouseEvent e) {
+        ((MouseMotionListener)a).mouseDragged(e);
+        ((MouseMotionListener)b).mouseDragged(e);
+    }
+
+    /**
+     * Handles the mouseMoved event by invoking the
+     * mouseMoved methods on listener-a and listener-b.
+     * @param e the mouse event
+     */
+    public void mouseMoved(MouseEvent e) {
+        ((MouseMotionListener)a).mouseMoved(e);
+        ((MouseMotionListener)b).mouseMoved(e);
+    }
+
+    /**
+     * Handles the windowOpened event by invoking the
+     * windowOpened methods on listener-a and listener-b.
+     * @param e the window event
+     */
+    public void windowOpened(WindowEvent e) {
+        ((WindowListener)a).windowOpened(e);
+        ((WindowListener)b).windowOpened(e);
+    }
+
+    /**
+     * Handles the windowClosing event by invoking the
+     * windowClosing methods on listener-a and listener-b.
+     * @param e the window event
+     */
+    public void windowClosing(WindowEvent e) {
+        ((WindowListener)a).windowClosing(e);
+        ((WindowListener)b).windowClosing(e);
+    }
+
+    /**
+     * Handles the windowClosed event by invoking the
+     * windowClosed methods on listener-a and listener-b.
+     * @param e the window event
+     */
+    public void windowClosed(WindowEvent e) {
+        ((WindowListener)a).windowClosed(e);
+        ((WindowListener)b).windowClosed(e);
+    }
+
+    /**
+     * Handles the windowIconified event by invoking the
+     * windowIconified methods on listener-a and listener-b.
+     * @param e the window event
+     */
+    public void windowIconified(WindowEvent e) {
+        ((WindowListener)a).windowIconified(e);
+        ((WindowListener)b).windowIconified(e);
+    }
+
+    /**
+     * Handles the windowDeiconified event by invoking the
+     * windowDeiconified methods on listener-a and listener-b.
+     * @param e the window event
+     */
+    public void windowDeiconified(WindowEvent e) {
+        ((WindowListener)a).windowDeiconified(e);
+        ((WindowListener)b).windowDeiconified(e);
+    }
+
+    /**
+     * Handles the windowActivated event by invoking the
+     * windowActivated methods on listener-a and listener-b.
+     * @param e the window event
+     */
+    public void windowActivated(WindowEvent e) {
+        ((WindowListener)a).windowActivated(e);
+        ((WindowListener)b).windowActivated(e);
+    }
+
+    /**
+     * Handles the windowDeactivated event by invoking the
+     * windowDeactivated methods on listener-a and listener-b.
+     * @param e the window event
+     */
+    public void windowDeactivated(WindowEvent e) {
+        ((WindowListener)a).windowDeactivated(e);
+        ((WindowListener)b).windowDeactivated(e);
+    }
+
+    /**
+     * Handles the windowStateChanged event by invoking the
+     * windowStateChanged methods on listener-a and listener-b.
+     * @param e the window event
+     * @since 1.4
+     */
+    public void windowStateChanged(WindowEvent e) {
+        ((WindowStateListener)a).windowStateChanged(e);
+        ((WindowStateListener)b).windowStateChanged(e);
+    }
+
+
+    /**
+     * Handles the windowGainedFocus event by invoking the windowGainedFocus
+     * methods on listener-a and listener-b.
+     * @param e the window event
+     * @since 1.4
+     */
+    public void windowGainedFocus(WindowEvent e) {
+        ((WindowFocusListener)a).windowGainedFocus(e);
+        ((WindowFocusListener)b).windowGainedFocus(e);
+    }
+
+    /**
+     * Handles the windowLostFocus event by invoking the windowLostFocus
+     * methods on listener-a and listener-b.
+     * @param e the window event
+     * @since 1.4
+     */
+    public void windowLostFocus(WindowEvent e) {
+        ((WindowFocusListener)a).windowLostFocus(e);
+        ((WindowFocusListener)b).windowLostFocus(e);
+    }
+
+    /**
+     * Handles the actionPerformed event by invoking the
+     * actionPerformed methods on listener-a and listener-b.
+     * @param e the action event
+     */
+    public void actionPerformed(ActionEvent e) {
+        ((ActionListener)a).actionPerformed(e);
+        ((ActionListener)b).actionPerformed(e);
+    }
+
+    /**
+     * Handles the itemStateChanged event by invoking the
+     * itemStateChanged methods on listener-a and listener-b.
+     * @param e the item event
+     */
+    public void itemStateChanged(ItemEvent e) {
+        ((ItemListener)a).itemStateChanged(e);
+        ((ItemListener)b).itemStateChanged(e);
+    }
+
+    /**
+     * Handles the adjustmentValueChanged event by invoking the
+     * adjustmentValueChanged methods on listener-a and listener-b.
+     * @param e the adjustment event
+     */
+    public void adjustmentValueChanged(AdjustmentEvent e) {
+        ((AdjustmentListener)a).adjustmentValueChanged(e);
+        ((AdjustmentListener)b).adjustmentValueChanged(e);
+    }
+    public void textValueChanged(TextEvent e) {
+        ((TextListener)a).textValueChanged(e);
+        ((TextListener)b).textValueChanged(e);
+    }
+
+    /**
+     * Handles the inputMethodTextChanged event by invoking the
+     * inputMethodTextChanged methods on listener-a and listener-b.
+     * @param e the item event
+     */
+    public void inputMethodTextChanged(InputMethodEvent e) {
+       ((InputMethodListener)a).inputMethodTextChanged(e);
+       ((InputMethodListener)b).inputMethodTextChanged(e);
+    }
+
+    /**
+     * Handles the caretPositionChanged event by invoking the
+     * caretPositionChanged methods on listener-a and listener-b.
+     * @param e the item event
+     */
+    public void caretPositionChanged(InputMethodEvent e) {
+       ((InputMethodListener)a).caretPositionChanged(e);
+       ((InputMethodListener)b).caretPositionChanged(e);
+    }
+
+    /**
+     * Handles the hierarchyChanged event by invoking the
+     * hierarchyChanged methods on listener-a and listener-b.
+     * @param e the item event
+     * @since 1.3
+     */
+    public void hierarchyChanged(HierarchyEvent e) {
+        ((HierarchyListener)a).hierarchyChanged(e);
+        ((HierarchyListener)b).hierarchyChanged(e);
+    }
+
+    /**
+     * Handles the ancestorMoved event by invoking the
+     * ancestorMoved methods on listener-a and listener-b.
+     * @param e the item event
+     * @since 1.3
+     */
+    public void ancestorMoved(HierarchyEvent e) {
+        ((HierarchyBoundsListener)a).ancestorMoved(e);
+        ((HierarchyBoundsListener)b).ancestorMoved(e);
+    }
+
+    /**
+     * Handles the ancestorResized event by invoking the
+     * ancestorResized methods on listener-a and listener-b.
+     * @param e the item event
+     * @since 1.3
+     */
+    public void ancestorResized(HierarchyEvent e) {
+        ((HierarchyBoundsListener)a).ancestorResized(e);
+        ((HierarchyBoundsListener)b).ancestorResized(e);
+    }
+
+    /**
+     * Handles the mouseWheelMoved event by invoking the
+     * mouseWheelMoved methods on listener-a and listener-b.
+     * @param e the mouse event
+     * @since 1.4
+     */
+    public void mouseWheelMoved(MouseWheelEvent e) {
+        ((MouseWheelListener)a).mouseWheelMoved(e);
+        ((MouseWheelListener)b).mouseWheelMoved(e);
+    }
+
+    /**
+     * Adds component-listener-a with component-listener-b and
+     * returns the resulting multicast listener.
+     * @param a component-listener-a
+     * @param b component-listener-b
+     * @return the resulting listener
+     */
+    public static ComponentListener add(ComponentListener a, ComponentListener b) {
+        return (ComponentListener)addInternal(a, b);
+    }
+
+    /**
+     * Adds container-listener-a with container-listener-b and
+     * returns the resulting multicast listener.
+     * @param a container-listener-a
+     * @param b container-listener-b
+     * @return the resulting listener
+     */
+    public static ContainerListener add(ContainerListener a, ContainerListener b) {
+        return (ContainerListener)addInternal(a, b);
+    }
+
+    /**
+     * Adds focus-listener-a with focus-listener-b and
+     * returns the resulting multicast listener.
+     * @param a focus-listener-a
+     * @param b focus-listener-b
+     * @return the resulting listener
+     */
+    public static FocusListener add(FocusListener a, FocusListener b) {
+        return (FocusListener)addInternal(a, b);
+    }
+
+    /**
+     * Adds key-listener-a with key-listener-b and
+     * returns the resulting multicast listener.
+     * @param a key-listener-a
+     * @param b key-listener-b
+     * @return the resulting listener
+     */
+    public static KeyListener add(KeyListener a, KeyListener b) {
+        return (KeyListener)addInternal(a, b);
+    }
+
+    /**
+     * Adds mouse-listener-a with mouse-listener-b and
+     * returns the resulting multicast listener.
+     * @param a mouse-listener-a
+     * @param b mouse-listener-b
+     * @return the resulting listener
+     */
+    public static MouseListener add(MouseListener a, MouseListener b) {
+        return (MouseListener)addInternal(a, b);
+    }
+
+    /**
+     * Adds mouse-motion-listener-a with mouse-motion-listener-b and
+     * returns the resulting multicast listener.
+     * @param a mouse-motion-listener-a
+     * @param b mouse-motion-listener-b
+     * @return the resulting listener
+     */
+    public static MouseMotionListener add(MouseMotionListener a, MouseMotionListener b) {
+        return (MouseMotionListener)addInternal(a, b);
+    }
+
+    /**
+     * Adds window-listener-a with window-listener-b and
+     * returns the resulting multicast listener.
+     * @param a window-listener-a
+     * @param b window-listener-b
+     * @return the resulting listener
+     */
+    public static WindowListener add(WindowListener a, WindowListener b) {
+        return (WindowListener)addInternal(a, b);
+    }
+
+    /**
+     * Adds window-state-listener-a with window-state-listener-b
+     * and returns the resulting multicast listener.
+     * @param a window-state-listener-a
+     * @param b window-state-listener-b
+     * @return the resulting listener
+     * @since 1.4
+     */
+    @SuppressWarnings("overloads")
+    public static WindowStateListener add(WindowStateListener a,
+                                          WindowStateListener b) {
+        return (WindowStateListener)addInternal(a, b);
+    }
+
+    /**
+     * Adds window-focus-listener-a with window-focus-listener-b
+     * and returns the resulting multicast listener.
+     * @param a window-focus-listener-a
+     * @param b window-focus-listener-b
+     * @return the resulting listener
+     * @since 1.4
+     */
+    public static WindowFocusListener add(WindowFocusListener a,
+                                          WindowFocusListener b) {
+        return (WindowFocusListener)addInternal(a, b);
+    }
+
+    /**
+     * Adds action-listener-a with action-listener-b and
+     * returns the resulting multicast listener.
+     * @param a action-listener-a
+     * @param b action-listener-b
+     * @return the resulting listener
+     */
+    @SuppressWarnings("overloads")
+    public static ActionListener add(ActionListener a, ActionListener b) {
+        return (ActionListener)addInternal(a, b);
+    }
+
+    /**
+     * Adds item-listener-a with item-listener-b and
+     * returns the resulting multicast listener.
+     * @param a item-listener-a
+     * @param b item-listener-b
+     * @return the resulting listener
+     */
+    @SuppressWarnings("overloads")
+    public static ItemListener add(ItemListener a, ItemListener b) {
+        return (ItemListener)addInternal(a, b);
+    }
+
+    /**
+     * Adds adjustment-listener-a with adjustment-listener-b and
+     * returns the resulting multicast listener.
+     * @param a adjustment-listener-a
+     * @param b adjustment-listener-b
+     * @return the resulting listener
+     */
+    @SuppressWarnings("overloads")
+    public static AdjustmentListener add(AdjustmentListener a, AdjustmentListener b) {
+        return (AdjustmentListener)addInternal(a, b);
+    }
+
+    /**
+     * Adds text-listener-a with text-listener-b and
+     * returns the resulting multicast listener.
+     *
+     * @param  a text-listener-a
+     * @param  b text-listener-b
+     * @return the resulting listener
+     */
+    @SuppressWarnings("overloads")
+    public static TextListener add(TextListener a, TextListener b) {
+        return (TextListener)addInternal(a, b);
+    }
+
+    /**
+     * Adds input-method-listener-a with input-method-listener-b and
+     * returns the resulting multicast listener.
+     * @param a input-method-listener-a
+     * @param b input-method-listener-b
+     * @return the resulting listener
+     */
+     public static InputMethodListener add(InputMethodListener a, InputMethodListener b) {
+        return (InputMethodListener)addInternal(a, b);
+     }
+
+    /**
+     * Adds hierarchy-listener-a with hierarchy-listener-b and
+     * returns the resulting multicast listener.
+     * @param a hierarchy-listener-a
+     * @param b hierarchy-listener-b
+     * @return the resulting listener
+     * @since 1.3
+     */
+    @SuppressWarnings("overloads")
+     public static HierarchyListener add(HierarchyListener a, HierarchyListener b) {
+        return (HierarchyListener)addInternal(a, b);
+     }
+
+    /**
+     * Adds hierarchy-bounds-listener-a with hierarchy-bounds-listener-b and
+     * returns the resulting multicast listener.
+     * @param a hierarchy-bounds-listener-a
+     * @param b hierarchy-bounds-listener-b
+     * @return the resulting listener
+     * @since 1.3
+     */
+     public static HierarchyBoundsListener add(HierarchyBoundsListener a, HierarchyBoundsListener b) {
+        return (HierarchyBoundsListener)addInternal(a, b);
+     }
+
+    /**
+     * Adds mouse-wheel-listener-a with mouse-wheel-listener-b and
+     * returns the resulting multicast listener.
+     * @param a mouse-wheel-listener-a
+     * @param b mouse-wheel-listener-b
+     * @return the resulting listener
+     * @since 1.4
+     */
+    @SuppressWarnings("overloads")
+    public static MouseWheelListener add(MouseWheelListener a,
+                                         MouseWheelListener b) {
+        return (MouseWheelListener)addInternal(a, b);
+    }
+
+    /**
+     * Removes the old component-listener from component-listener-l and
+     * returns the resulting multicast listener.
+     * @param l component-listener-l
+     * @param oldl the component-listener being removed
+     * @return the resulting listener
+     */
+    public static ComponentListener remove(ComponentListener l, ComponentListener oldl) {
+        return (ComponentListener) removeInternal(l, oldl);
+    }
+
+    /**
+     * Removes the old container-listener from container-listener-l and
+     * returns the resulting multicast listener.
+     * @param l container-listener-l
+     * @param oldl the container-listener being removed
+     * @return the resulting listener
+     */
+    public static ContainerListener remove(ContainerListener l, ContainerListener oldl) {
+        return (ContainerListener) removeInternal(l, oldl);
+    }
+
+    /**
+     * Removes the old focus-listener from focus-listener-l and
+     * returns the resulting multicast listener.
+     * @param l focus-listener-l
+     * @param oldl the focus-listener being removed
+     * @return the resulting listener
+     */
+    public static FocusListener remove(FocusListener l, FocusListener oldl) {
+        return (FocusListener) removeInternal(l, oldl);
+    }
+
+    /**
+     * Removes the old key-listener from key-listener-l and
+     * returns the resulting multicast listener.
+     * @param l key-listener-l
+     * @param oldl the key-listener being removed
+     * @return the resulting listener
+     */
+    public static KeyListener remove(KeyListener l, KeyListener oldl) {
+        return (KeyListener) removeInternal(l, oldl);
+    }
+
+    /**
+     * Removes the old mouse-listener from mouse-listener-l and
+     * returns the resulting multicast listener.
+     * @param l mouse-listener-l
+     * @param oldl the mouse-listener being removed
+     * @return the resulting listener
+     */
+    public static MouseListener remove(MouseListener l, MouseListener oldl) {
+        return (MouseListener) removeInternal(l, oldl);
+    }
+
+    /**
+     * Removes the old mouse-motion-listener from mouse-motion-listener-l
+     * and returns the resulting multicast listener.
+     * @param l mouse-motion-listener-l
+     * @param oldl the mouse-motion-listener being removed
+     * @return the resulting listener
+     */
+    public static MouseMotionListener remove(MouseMotionListener l, MouseMotionListener oldl) {
+        return (MouseMotionListener) removeInternal(l, oldl);
+    }
+
+    /**
+     * Removes the old window-listener from window-listener-l and
+     * returns the resulting multicast listener.
+     * @param l window-listener-l
+     * @param oldl the window-listener being removed
+     * @return the resulting listener
+     */
+    public static WindowListener remove(WindowListener l, WindowListener oldl) {
+        return (WindowListener) removeInternal(l, oldl);
+    }
+
+    /**
+     * Removes the old window-state-listener from window-state-listener-l
+     * and returns the resulting multicast listener.
+     * @param l window-state-listener-l
+     * @param oldl the window-state-listener being removed
+     * @return the resulting listener
+     * @since 1.4
+     */
+    @SuppressWarnings("overloads")
+    public static WindowStateListener remove(WindowStateListener l,
+                                             WindowStateListener oldl) {
+        return (WindowStateListener) removeInternal(l, oldl);
+    }
+
+    /**
+     * Removes the old window-focus-listener from window-focus-listener-l
+     * and returns the resulting multicast listener.
+     * @param l window-focus-listener-l
+     * @param oldl the window-focus-listener being removed
+     * @return the resulting listener
+     * @since 1.4
+     */
+    public static WindowFocusListener remove(WindowFocusListener l,
+                                             WindowFocusListener oldl) {
+        return (WindowFocusListener) removeInternal(l, oldl);
+    }
+
+    /**
+     * Removes the old action-listener from action-listener-l and
+     * returns the resulting multicast listener.
+     * @param l action-listener-l
+     * @param oldl the action-listener being removed
+     * @return the resulting listener
+     */
+    @SuppressWarnings("overloads")
+    public static ActionListener remove(ActionListener l, ActionListener oldl) {
+        return (ActionListener) removeInternal(l, oldl);
+    }
+
+    /**
+     * Removes the old item-listener from item-listener-l and
+     * returns the resulting multicast listener.
+     * @param l item-listener-l
+     * @param oldl the item-listener being removed
+     * @return the resulting listener
+     */
+    @SuppressWarnings("overloads")
+    public static ItemListener remove(ItemListener l, ItemListener oldl) {
+        return (ItemListener) removeInternal(l, oldl);
+    }
+
+    /**
+     * Removes the old adjustment-listener from adjustment-listener-l and
+     * returns the resulting multicast listener.
+     * @param l adjustment-listener-l
+     * @param oldl the adjustment-listener being removed
+     * @return the resulting listener
+     */
+    @SuppressWarnings("overloads")
+    public static AdjustmentListener remove(AdjustmentListener l, AdjustmentListener oldl) {
+        return (AdjustmentListener) removeInternal(l, oldl);
+    }
+
+    /**
+     * Removes the old text-listener from text-listener-l and
+     * returns the resulting multicast listener.
+     *
+     * @param  l text-listener-l
+     * @param  oldl the text-listener being removed
+     * @return the resulting listener
+     */
+    @SuppressWarnings("overloads")
+    public static TextListener remove(TextListener l, TextListener oldl) {
+        return (TextListener) removeInternal(l, oldl);
+    }
+
+    /**
+     * Removes the old input-method-listener from input-method-listener-l and
+     * returns the resulting multicast listener.
+     * @param l input-method-listener-l
+     * @param oldl the input-method-listener being removed
+     * @return the resulting listener
+     */
+    public static InputMethodListener remove(InputMethodListener l, InputMethodListener oldl) {
+        return (InputMethodListener) removeInternal(l, oldl);
+    }
+
+    /**
+     * Removes the old hierarchy-listener from hierarchy-listener-l and
+     * returns the resulting multicast listener.
+     * @param l hierarchy-listener-l
+     * @param oldl the hierarchy-listener being removed
+     * @return the resulting listener
+     * @since 1.3
+     */
+    @SuppressWarnings("overloads")
+    public static HierarchyListener remove(HierarchyListener l, HierarchyListener oldl) {
+        return (HierarchyListener) removeInternal(l, oldl);
+    }
+
+    /**
+     * Removes the old hierarchy-bounds-listener from
+     * hierarchy-bounds-listener-l and returns the resulting multicast
+     * listener.
+     * @param l hierarchy-bounds-listener-l
+     * @param oldl the hierarchy-bounds-listener being removed
+     * @return the resulting listener
+     * @since 1.3
+     */
+    public static HierarchyBoundsListener remove(HierarchyBoundsListener l, HierarchyBoundsListener oldl) {
+        return (HierarchyBoundsListener) removeInternal(l, oldl);
+    }
+
+    /**
+     * Removes the old mouse-wheel-listener from mouse-wheel-listener-l
+     * and returns the resulting multicast listener.
+     * @param l mouse-wheel-listener-l
+     * @param oldl the mouse-wheel-listener being removed
+     * @return the resulting listener
+     * @since 1.4
+     */
+    @SuppressWarnings("overloads")
+    public static MouseWheelListener remove(MouseWheelListener l,
+                                            MouseWheelListener oldl) {
+      return (MouseWheelListener) removeInternal(l, oldl);
+    }
+
+    /**
+     * Returns the resulting multicast listener from adding listener-a
+     * and listener-b together.
+     * If listener-a is null, it returns listener-b;
+     * If listener-b is null, it returns listener-a
+     * If neither are null, then it creates and returns
+     * a new AWTEventMulticaster instance which chains a with b.
+     * @param a event listener-a
+     * @param b event listener-b
+     * @return the resulting listener
+     */
+    protected static EventListener addInternal(EventListener a, EventListener b) {
+        if (a == null)  return b;
+        if (b == null)  return a;
+        return new AWTEventMulticaster(a, b);
+    }
+
+    /**
+     * Returns the resulting multicast listener after removing the
+     * old listener from listener-l.
+     * If listener-l equals the old listener OR listener-l is null,
+     * returns null.
+     * Else if listener-l is an instance of AWTEventMulticaster,
+     * then it removes the old listener from it.
+     * Else, returns listener l.
+     * @param l the listener being removed from
+     * @param oldl the listener being removed
+     * @return the resulting listener
+     */
+    protected static EventListener removeInternal(EventListener l, EventListener oldl) {
+        if (l == oldl || l == null) {
+            return null;
+        } else if (l instanceof AWTEventMulticaster) {
+            return ((AWTEventMulticaster)l).remove(oldl);
+        } else {
+            return l;           // it's not here
+        }
+    }
+
+
+   /**
+    * Serialization support. Saves all Serializable listeners
+    * to a serialization stream.
+    *
+    * @param  s the stream to save to
+    * @param  k a prefix stream to put before each serializable listener
+    * @throws IOException if serialization fails
+    */
+    protected void saveInternal(ObjectOutputStream s, String k) throws IOException {
+        if (a instanceof AWTEventMulticaster) {
+            ((AWTEventMulticaster)a).saveInternal(s, k);
+        }
+        else if (a instanceof Serializable) {
+            s.writeObject(k);
+            s.writeObject(a);
+        }
+
+        if (b instanceof AWTEventMulticaster) {
+            ((AWTEventMulticaster)b).saveInternal(s, k);
+        }
+        else if (b instanceof Serializable) {
+            s.writeObject(k);
+            s.writeObject(b);
+        }
+    }
+
+   /**
+    * Saves a Serializable listener chain to a serialization stream.
+    *
+    * @param  s the stream to save to
+    * @param  k a prefix stream to put before each serializable listener
+    * @param  l the listener chain to save
+    * @throws IOException if serialization fails
+    */
+    protected static void save(ObjectOutputStream s, String k, EventListener l) throws IOException {
+      if (l == null) {
+          return;
+      }
+      else if (l instanceof AWTEventMulticaster) {
+          ((AWTEventMulticaster)l).saveInternal(s, k);
+      }
+      else if (l instanceof Serializable) {
+           s.writeObject(k);
+           s.writeObject(l);
+      }
+    }
+
+    /*
+     * Recursive method which returns a count of the number of listeners in
+     * EventListener, handling the (common) case of l actually being an
+     * AWTEventMulticaster.  Additionally, only listeners of type listenerType
+     * are counted.  Method modified to fix bug 4513402.  -bchristi
+     */
+    private static int getListenerCount(EventListener l, Class<?> listenerType) {
+        if (l instanceof AWTEventMulticaster) {
+            AWTEventMulticaster mc = (AWTEventMulticaster)l;
+            return getListenerCount(mc.a, listenerType) +
+             getListenerCount(mc.b, listenerType);
+        }
+        else {
+            // Only count listeners of correct type
+            return listenerType.isInstance(l) ? 1 : 0;
+        }
+    }
+
+    /*
+     * Recursive method which populates EventListener array a with EventListeners
+     * from l.  l is usually an AWTEventMulticaster.  Bug 4513402 revealed that
+     * if l differed in type from the element type of a, an ArrayStoreException
+     * would occur.  Now l is only inserted into a if it's of the appropriate
+     * type.  -bchristi
+     */
+    private static int populateListenerArray(EventListener[] a, EventListener l, int index) {
+        if (l instanceof AWTEventMulticaster) {
+            AWTEventMulticaster mc = (AWTEventMulticaster)l;
+            int lhs = populateListenerArray(a, mc.a, index);
+            return populateListenerArray(a, mc.b, lhs);
+        }
+        else if (a.getClass().getComponentType().isInstance(l)) {
+            a[index] = l;
+            return index + 1;
+        }
+        // Skip nulls, instances of wrong class
+        else {
+            return index;
+        }
+    }
+
+    /**
+     * Returns an array of all the objects chained as
+     * <code><em>Foo</em>Listener</code>s by the specified
+     * {@code java.util.EventListener}.
+     * <code><em>Foo</em>Listener</code>s are chained by the
+     * {@code AWTEventMulticaster} using the
+     * <code>add<em>Foo</em>Listener</code> method.
+     * If a {@code null} listener is specified, this method returns an
+     * empty array. If the specified listener is not an instance of
+     * {@code AWTEventMulticaster}, this method returns an array which
+     * contains only the specified listener. If no such listeners are chained,
+     * this method returns an empty array.
+     *
+     * @param <T> the listener type
+     * @param l the specified {@code java.util.EventListener}
+     * @param listenerType the type of listeners requested; this parameter
+     *          should specify an interface that descends from
+     *          {@code java.util.EventListener}
+     * @return an array of all objects chained as
+     *          <code><em>Foo</em>Listener</code>s by the specified multicast
+     *          listener, or an empty array if no such listeners have been
+     *          chained by the specified multicast listener
+     * @exception NullPointerException if the specified
+     *             {@code listenertype} parameter is {@code null}
+     * @exception ClassCastException if {@code listenerType}
+     *          doesn't specify a class or interface that implements
+     *          {@code java.util.EventListener}
+     *
+     * @since 1.4
+     */
+    @SuppressWarnings("unchecked")
+    public static <T extends EventListener> T[]
+        getListeners(EventListener l, Class<T> listenerType)
+    {
+        if (listenerType == null) {
+            throw new NullPointerException ("Listener type should not be null");
+        }
+
+        int n = getListenerCount(l, listenerType);
+        T[] result = (T[])Array.newInstance(listenerType, n);
+        populateListenerArray(result, l, 0);
+        return result;
+    }
+}