/*
 * Copyright (c) 2001, 2014, 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 AWTEventMulticaster to implement efficient and thread-safe multi-cast event dispatching for the drag-and-drop events defined in the java.awt.dnd package.
See Also:
Since: 1.4
/** * A class extends {@code AWTEventMulticaster} 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 a and b should not be null, though implementations may vary in choosing whether or not to throw NullPointerException in that case.
Params:
  • a – listener-a
  • b – listener-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 DnDEventMulticaster(EventListener a, EventListener b) { super(a,b); }
Handles the DragSourceDragEvent by invoking dragEnter on listener-a and listener-b.
Params:
  • dsde – the DragSourceDragEvent
/** * Handles the {@code DragSourceDragEvent} by invoking * {@code dragEnter} on listener-a and listener-b. * * @param dsde the {@code DragSourceDragEvent} */
public void dragEnter(DragSourceDragEvent dsde) { ((DragSourceListener)a).dragEnter(dsde); ((DragSourceListener)b).dragEnter(dsde); }
Handles the DragSourceDragEvent by invoking dragOver on listener-a and listener-b.
Params:
  • dsde – the DragSourceDragEvent
/** * Handles the {@code DragSourceDragEvent} by invoking * {@code dragOver} on listener-a and listener-b. * * @param dsde the {@code DragSourceDragEvent} */
public void dragOver(DragSourceDragEvent dsde) { ((DragSourceListener)a).dragOver(dsde); ((DragSourceListener)b).dragOver(dsde); }
Handles the DragSourceDragEvent by invoking dropActionChanged on listener-a and listener-b.
Params:
  • dsde – the DragSourceDragEvent
/** * Handles the {@code DragSourceDragEvent} by invoking * {@code dropActionChanged} on listener-a and listener-b. * * @param dsde the {@code DragSourceDragEvent} */
public void dropActionChanged(DragSourceDragEvent dsde) { ((DragSourceListener)a).dropActionChanged(dsde); ((DragSourceListener)b).dropActionChanged(dsde); }
Handles the DragSourceEvent by invoking dragExit on listener-a and listener-b.
Params:
  • dse – the DragSourceEvent
/** * Handles the {@code DragSourceEvent} by invoking * {@code dragExit} on listener-a and listener-b. * * @param dse the {@code DragSourceEvent} */
public void dragExit(DragSourceEvent dse) { ((DragSourceListener)a).dragExit(dse); ((DragSourceListener)b).dragExit(dse); }
Handles the DragSourceDropEvent by invoking dragDropEnd on listener-a and listener-b.
Params:
  • dsde – the DragSourceDropEvent
/** * Handles the {@code DragSourceDropEvent} by invoking * {@code dragDropEnd} on listener-a and listener-b. * * @param dsde the {@code DragSourceDropEvent} */
public void dragDropEnd(DragSourceDropEvent dsde) { ((DragSourceListener)a).dragDropEnd(dsde); ((DragSourceListener)b).dragDropEnd(dsde); }
Handles the DragSourceDragEvent by invoking dragMouseMoved on listener-a and listener-b.
Params:
  • dsde – the DragSourceDragEvent
/** * Handles the {@code DragSourceDragEvent} by invoking * {@code dragMouseMoved} on listener-a and listener-b. * * @param dsde the {@code DragSourceDragEvent} */
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.
Params:
  • a – drag-source-listener-a
  • b – drag-source-listener-b
/** * 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.
Params:
  • a – drag-source-motion-listener-a
  • b – drag-source-motion-listener-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 */
@SuppressWarnings("overloads") 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.
Params:
  • l – drag-source-listener-l
  • oldl – the drag-source-listener being removed
/** * 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.
Params:
  • l – drag-source-motion-listener-l
  • ol – the drag-source-motion-listener being removed
/** * 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 */
@SuppressWarnings("overloads") 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.
Params:
  • a – event listener-a
  • b – event listener-b
/** * 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.
Params:
  • oldl – the listener to be removed
/** * 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.
Params:
  • l – the listener being removed from
  • oldl – the listener being removed
/** * 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); } }