| /* |
| * Copyright (c) 2001, 2007, 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.dnd; |
| |
| import java.awt.AWTEventMulticaster; |
| import java.io.ObjectOutputStream; |
| import java.io.IOException; |
| import java.util.EventListener; |
| |
| |
| /** |
| * A class extends <code>AWTEventMulticaster</code> to implement efficient and |
| * thread-safe multi-cast event dispatching for the drag-and-drop events defined |
| * in the java.awt.dnd package. |
| * |
| * @since 1.4 |
| * @see AWTEventMulticaster |
| */ |
| |
| class DnDEventMulticaster extends AWTEventMulticaster |
| implements DragSourceListener, DragSourceMotionListener { |
| |
| /** |
| * Creates an event multicaster instance which chains listener-a |
| * with listener-b. Input parameters <code>a</code> and <code>b</code> |
| * should not be <code>null</code>, though implementations may vary in |
| * choosing whether or not to throw <code>NullPointerException</code> |
| * in that case. |
| * |
| * @param a listener-a |
| * @param b listener-b |
| */ |
| protected DnDEventMulticaster(EventListener a, EventListener b) { |
| super(a,b); |
| } |
| |
| /** |
| * Handles the <code>DragSourceDragEvent</code> by invoking |
| * <code>dragEnter</code> on listener-a and listener-b. |
| * |
| * @param dsde the <code>DragSourceDragEvent</code> |
| */ |
| public void dragEnter(DragSourceDragEvent dsde) { |
| ((DragSourceListener)a).dragEnter(dsde); |
| ((DragSourceListener)b).dragEnter(dsde); |
| } |
| |
| /** |
| * Handles the <code>DragSourceDragEvent</code> by invoking |
| * <code>dragOver</code> on listener-a and listener-b. |
| * |
| * @param e the <code>DragSourceDragEvent</code> |
| */ |
| public void dragOver(DragSourceDragEvent dsde) { |
| ((DragSourceListener)a).dragOver(dsde); |
| ((DragSourceListener)b).dragOver(dsde); |
| } |
| |
| /** |
| * Handles the <code>DragSourceDragEvent</code> by invoking |
| * <code>dropActionChanged</code> on listener-a and listener-b. |
| * |
| * @param dsde the <code>DragSourceDragEvent</code> |
| */ |
| public void dropActionChanged(DragSourceDragEvent dsde) { |
| ((DragSourceListener)a).dropActionChanged(dsde); |
| ((DragSourceListener)b).dropActionChanged(dsde); |
| } |
| |
| /** |
| * Handles the <code>DragSourceEvent</code> by invoking |
| * <code>dragExit</code> on listener-a and listener-b. |
| * |
| * @param dse the <code>DragSourceEvent</code> |
| */ |
| public void dragExit(DragSourceEvent dse) { |
| ((DragSourceListener)a).dragExit(dse); |
| ((DragSourceListener)b).dragExit(dse); |
| } |
| |
| /** |
| * Handles the <code>DragSourceDropEvent</code> by invoking |
| * <code>dragDropEnd</code> on listener-a and listener-b. |
| * |
| * @param dsde the <code>DragSourceDropEvent</code> |
| */ |
| public void dragDropEnd(DragSourceDropEvent dsde) { |
| ((DragSourceListener)a).dragDropEnd(dsde); |
| ((DragSourceListener)b).dragDropEnd(dsde); |
| } |
| |
| /** |
| * Handles the <code>DragSourceDragEvent</code> by invoking |
| * <code>dragMouseMoved</code> on listener-a and listener-b. |
| * |
| * @param dsde the <code>DragSourceDragEvent</code> |
| */ |
| public void dragMouseMoved(DragSourceDragEvent dsde) { |
| ((DragSourceMotionListener)a).dragMouseMoved(dsde); |
| ((DragSourceMotionListener)b).dragMouseMoved(dsde); |
| } |
| |
| /** |
| * Adds drag-source-listener-a with drag-source-listener-b and |
| * returns the resulting multicast listener. |
| * |
| * @param a drag-source-listener-a |
| * @param b drag-source-listener-b |
| */ |
| public static DragSourceListener add(DragSourceListener a, |
| DragSourceListener b) { |
| return (DragSourceListener)addInternal(a, b); |
| } |
| |
| /** |
| * Adds drag-source-motion-listener-a with drag-source-motion-listener-b and |
| * returns the resulting multicast listener. |
| * |
| * @param a drag-source-motion-listener-a |
| * @param b drag-source-motion-listener-b |
| */ |
| public static DragSourceMotionListener add(DragSourceMotionListener a, |
| DragSourceMotionListener b) { |
| return (DragSourceMotionListener)addInternal(a, b); |
| } |
| |
| /** |
| * Removes the old drag-source-listener from drag-source-listener-l |
| * and returns the resulting multicast listener. |
| * |
| * @param l drag-source-listener-l |
| * @param oldl the drag-source-listener being removed |
| */ |
| public static DragSourceListener remove(DragSourceListener l, |
| DragSourceListener oldl) { |
| return (DragSourceListener)removeInternal(l, oldl); |
| } |
| |
| /** |
| * Removes the old drag-source-motion-listener from |
| * drag-source-motion-listener-l and returns the resulting multicast |
| * listener. |
| * |
| * @param l drag-source-motion-listener-l |
| * @param ol the drag-source-motion-listener being removed |
| */ |
| public static DragSourceMotionListener remove(DragSourceMotionListener l, |
| DragSourceMotionListener ol) { |
| return (DragSourceMotionListener)removeInternal(l, ol); |
| } |
| |
| /** |
| * 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 |
| */ |
| protected static EventListener addInternal(EventListener a, EventListener b) { |
| if (a == null) return b; |
| if (b == null) return a; |
| return new DnDEventMulticaster(a, b); |
| } |
| |
| /** |
| * Removes a listener from this multicaster and returns the |
| * resulting multicast listener. |
| * @param oldl the listener to be removed |
| */ |
| 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); |
| } |
| |
| /** |
| * 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 |
| */ |
| protected static EventListener removeInternal(EventListener l, EventListener oldl) { |
| if (l == oldl || l == null) { |
| return null; |
| } else if (l instanceof DnDEventMulticaster) { |
| return ((DnDEventMulticaster)l).remove(oldl); |
| } else { |
| return l; // it's not here |
| } |
| } |
| |
| protected static void save(ObjectOutputStream s, String k, EventListener l) |
| throws IOException { |
| AWTEventMulticaster.save(s, k, l); |
| } |
| } |