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| 1 | /* | ||
| 2 | * Copyright (c) 2001, 2007, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | package java.awt.dnd; | ||
| 26 | |||
| 27 | import java.awt.AWTEventMulticaster; | ||
| 28 | import java.io.ObjectOutputStream; | ||
| 29 | import java.io.IOException; | ||
| 30 | import java.util.EventListener; | ||
| 31 | |||
| 32 | |||
| 33 | /** | ||
| 34 | * A class extends <code>AWTEventMulticaster</code> to implement efficient and | ||
| 35 | * thread-safe multi-cast event dispatching for the drag-and-drop events defined | ||
| 36 | * in the java.awt.dnd package. | ||
| 37 | * | ||
| 38 | * @since 1.4 | ||
| 39 | * @see AWTEventMulticaster | ||
| 40 | */ | ||
| 41 | |||
| 42 | class DnDEventMulticaster extends AWTEventMulticaster | ||
| 43 | implements DragSourceListener, DragSourceMotionListener { | ||
| 44 | |||
| 45 | /** | ||
| 46 | * Creates an event multicaster instance which chains listener-a | ||
| 47 | * with listener-b. Input parameters <code>a</code> and <code>b</code> | ||
| 48 | * should not be <code>null</code>, though implementations may vary in | ||
| 49 | * choosing whether or not to throw <code>NullPointerException</code> | ||
| 50 | * in that case. | ||
| 51 | * | ||
| 52 | * @param a listener-a | ||
| 53 | * @param b listener-b | ||
| 54 | */ | ||
| 55 | protected DnDEventMulticaster(EventListener a, EventListener b) { | ||
| 56 | super(a,b); | ||
| 57 | } | ||
| 58 | |||
| 59 | /** | ||
| 60 | * Handles the <code>DragSourceDragEvent</code> by invoking | ||
| 61 | * <code>dragEnter</code> on listener-a and listener-b. | ||
| 62 | * | ||
| 63 | * @param dsde the <code>DragSourceDragEvent</code> | ||
| 64 | */ | ||
| 65 | public void dragEnter(DragSourceDragEvent dsde) { | ||
| 66 | ((DragSourceListener)a).dragEnter(dsde); | ||
| 67 | ((DragSourceListener)b).dragEnter(dsde); | ||
| 68 | } | ||
| 69 | |||
| 70 | /** | ||
| 71 | * Handles the <code>DragSourceDragEvent</code> by invoking | ||
| 72 | * <code>dragOver</code> on listener-a and listener-b. | ||
| 73 | * | ||
| 74 | * @param e the <code>DragSourceDragEvent</code> | ||
| 75 | */ | ||
| 76 | public void dragOver(DragSourceDragEvent dsde) { | ||
| 77 | ((DragSourceListener)a).dragOver(dsde); | ||
| 78 | ((DragSourceListener)b).dragOver(dsde); | ||
| 79 | } | ||
| 80 | |||
| 81 | /** | ||
| 82 | * Handles the <code>DragSourceDragEvent</code> by invoking | ||
| 83 | * <code>dropActionChanged</code> on listener-a and listener-b. | ||
| 84 | * | ||
| 85 | * @param dsde the <code>DragSourceDragEvent</code> | ||
| 86 | */ | ||
| 87 | public void dropActionChanged(DragSourceDragEvent dsde) { | ||
| 88 | ((DragSourceListener)a).dropActionChanged(dsde); | ||
| 89 | ((DragSourceListener)b).dropActionChanged(dsde); | ||
| 90 | } | ||
| 91 | |||
| 92 | /** | ||
| 93 | * Handles the <code>DragSourceEvent</code> by invoking | ||
| 94 | * <code>dragExit</code> on listener-a and listener-b. | ||
| 95 | * | ||
| 96 | * @param dse the <code>DragSourceEvent</code> | ||
| 97 | */ | ||
| 98 | public void dragExit(DragSourceEvent dse) { | ||
| 99 | ((DragSourceListener)a).dragExit(dse); | ||
| 100 | ((DragSourceListener)b).dragExit(dse); | ||
| 101 | } | ||
| 102 | |||
| 103 | /** | ||
| 104 | * Handles the <code>DragSourceDropEvent</code> by invoking | ||
| 105 | * <code>dragDropEnd</code> on listener-a and listener-b. | ||
| 106 | * | ||
| 107 | * @param dsde the <code>DragSourceDropEvent</code> | ||
| 108 | */ | ||
| 109 | public void dragDropEnd(DragSourceDropEvent dsde) { | ||
| 110 | ((DragSourceListener)a).dragDropEnd(dsde); | ||
| 111 | ((DragSourceListener)b).dragDropEnd(dsde); | ||
| 112 | } | ||
| 113 | |||
| 114 | /** | ||
| 115 | * Handles the <code>DragSourceDragEvent</code> by invoking | ||
| 116 | * <code>dragMouseMoved</code> on listener-a and listener-b. | ||
| 117 | * | ||
| 118 | * @param dsde the <code>DragSourceDragEvent</code> | ||
| 119 | */ | ||
| 120 | public void dragMouseMoved(DragSourceDragEvent dsde) { | ||
| 121 | ((DragSourceMotionListener)a).dragMouseMoved(dsde); | ||
| 122 | ((DragSourceMotionListener)b).dragMouseMoved(dsde); | ||
| 123 | } | ||
| 124 | |||
| 125 | /** | ||
| 126 | * Adds drag-source-listener-a with drag-source-listener-b and | ||
| 127 | * returns the resulting multicast listener. | ||
| 128 | * | ||
| 129 | * @param a drag-source-listener-a | ||
| 130 | * @param b drag-source-listener-b | ||
| 131 | */ | ||
| 132 | public static DragSourceListener add(DragSourceListener a, | ||
| 133 | DragSourceListener b) { | ||
| 134 | return (DragSourceListener)addInternal(a, b); | ||
| 135 | } | ||
| 136 | |||
| 137 | /** | ||
| 138 | * Adds drag-source-motion-listener-a with drag-source-motion-listener-b and | ||
| 139 | * returns the resulting multicast listener. | ||
| 140 | * | ||
| 141 | * @param a drag-source-motion-listener-a | ||
| 142 | * @param b drag-source-motion-listener-b | ||
| 143 | */ | ||
| 144 | public static DragSourceMotionListener add(DragSourceMotionListener a, | ||
| 145 | DragSourceMotionListener b) { | ||
| 146 | return (DragSourceMotionListener)addInternal(a, b); | ||
| 147 | } | ||
| 148 | |||
| 149 | /** | ||
| 150 | * Removes the old drag-source-listener from drag-source-listener-l | ||
| 151 | * and returns the resulting multicast listener. | ||
| 152 | * | ||
| 153 | * @param l drag-source-listener-l | ||
| 154 | * @param oldl the drag-source-listener being removed | ||
| 155 | */ | ||
| 156 | public static DragSourceListener remove(DragSourceListener l, | ||
| 157 | DragSourceListener oldl) { | ||
| 158 | return (DragSourceListener)removeInternal(l, oldl); | ||
| 159 | } | ||
| 160 | |||
| 161 | /** | ||
| 162 | * Removes the old drag-source-motion-listener from | ||
| 163 | * drag-source-motion-listener-l and returns the resulting multicast | ||
| 164 | * listener. | ||
| 165 | * | ||
| 166 | * @param l drag-source-motion-listener-l | ||
| 167 | * @param ol the drag-source-motion-listener being removed | ||
| 168 | */ | ||
| 169 | public static DragSourceMotionListener remove(DragSourceMotionListener l, | ||
| 170 | DragSourceMotionListener ol) { | ||
| 171 | return (DragSourceMotionListener)removeInternal(l, ol); | ||
| 172 | } | ||
| 173 | |||
| 174 | /** | ||
| 175 | * Returns the resulting multicast listener from adding listener-a | ||
| 176 | * and listener-b together. | ||
| 177 | * If listener-a is null, it returns listener-b; | ||
| 178 | * If listener-b is null, it returns listener-a | ||
| 179 | * If neither are null, then it creates and returns | ||
| 180 | * a new AWTEventMulticaster instance which chains a with b. | ||
| 181 | * @param a event listener-a | ||
| 182 | * @param b event listener-b | ||
| 183 | */ | ||
| 184 | protected static EventListener addInternal(EventListener a, EventListener b) { | ||
| 185 | if (a == null) return b; | ||
| 186 | if (b == null) return a; | ||
| 187 | return new DnDEventMulticaster(a, b); | ||
| 188 | } | ||
| 189 | |||
| 190 | /** | ||
| 191 | * Removes a listener from this multicaster and returns the | ||
| 192 | * resulting multicast listener. | ||
| 193 | * @param oldl the listener to be removed | ||
| 194 | */ | ||
| 195 | protected EventListener remove(EventListener oldl) { | ||
| 196 | if (oldl == a) return b; | ||
| 197 | if (oldl == b) return a; | ||
| 198 | EventListener a2 = removeInternal(a, oldl); | ||
| 199 | EventListener b2 = removeInternal(b, oldl); | ||
| 200 | if (a2 == a && b2 == b) { | ||
| 201 | return this; // it's not here | ||
| 202 | } | ||
| 203 | return addInternal(a2, b2); | ||
| 204 | } | ||
| 205 | |||
| 206 | /** | ||
| 207 | * Returns the resulting multicast listener after removing the | ||
| 208 | * old listener from listener-l. | ||
| 209 | * If listener-l equals the old listener OR listener-l is null, | ||
| 210 | * returns null. | ||
| 211 | * Else if listener-l is an instance of AWTEventMulticaster, | ||
| 212 | * then it removes the old listener from it. | ||
| 213 | * Else, returns listener l. | ||
| 214 | * @param l the listener being removed from | ||
| 215 | * @param oldl the listener being removed | ||
| 216 | */ | ||
| 217 | protected static EventListener removeInternal(EventListener l, EventListener oldl) { | ||
| 218 | if (l == oldl || l == null) { | ||
| 219 | return null; | ||
| 220 | } else if (l instanceof DnDEventMulticaster) { | ||
| 221 | return ((DnDEventMulticaster)l).remove(oldl); | ||
| 222 | } else { | ||
| 223 | return l; // it's not here | ||
| 224 | } | ||
| 225 | } | ||
| 226 | |||
| 227 | protected static void save(ObjectOutputStream s, String k, EventListener l) | ||
| 228 | throws IOException { | ||
| 229 | AWTEventMulticaster.save(s, k, l); | ||
| 230 | } | ||
| 231 | } | ||