| /* |
| * Copyright (c) 1997, 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 sun.applet; |
| |
| import java.util.EventListener; |
| import java.io.Serializable; |
| import java.io.ObjectOutputStream; |
| import java.io.IOException; |
| |
| /** |
| * AppletEventMulticaster class. This class manages an immutable |
| * structure consisting of a chain of AppletListeners and is |
| * responsible for dispatching events to them. |
| * |
| * @author Sunita Mani |
| * |
| * @deprecated The Applet API is deprecated. See the |
| * <a href="../../java/applet/package-summary.html"> java.applet package |
| * documentation</a> for further information. |
| */ |
| @Deprecated(since = "9") |
| public class AppletEventMulticaster implements AppletListener { |
| |
| private final AppletListener a, b; |
| |
| public AppletEventMulticaster(AppletListener a, AppletListener b) { |
| this.a = a; this.b = b; |
| } |
| |
| public void appletStateChanged(AppletEvent e) { |
| a.appletStateChanged(e); |
| b.appletStateChanged(e); |
| } |
| |
| /** |
| * Adds Applet-listener-a with Applet-listener-b and |
| * returns the resulting multicast listener. |
| * @param a Applet-listener-a |
| * @param b Applet-listener-b |
| */ |
| public static AppletListener add(AppletListener a, AppletListener b) { |
| return addInternal(a, b); |
| } |
| |
| /** |
| * Removes the old Applet-listener from Applet-listener-l and |
| * returns the resulting multicast listener. |
| * @param l Applet-listener-l |
| * @param oldl the Applet-listener being removed |
| */ |
| public static AppletListener remove(AppletListener l, AppletListener oldl) { |
| return 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 AppletEventMulticaster instance which chains a with b. |
| * @param a event listener-a |
| * @param b event listener-b |
| */ |
| private static AppletListener addInternal(AppletListener a, AppletListener b) { |
| if (a == null) return b; |
| if (b == null) return a; |
| return new AppletEventMulticaster(a, b); |
| } |
| |
| |
| /** |
| * Removes a listener from this multicaster and returns the |
| * resulting multicast listener. |
| * @param oldl the listener to be removed |
| */ |
| protected AppletListener remove(AppletListener oldl) { |
| if (oldl == a) return b; |
| if (oldl == b) return a; |
| AppletListener a2 = removeInternal(a, oldl); |
| AppletListener 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 AppletEventMulticaster |
| * 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 |
| */ |
| private static AppletListener removeInternal(AppletListener l, AppletListener oldl) { |
| if (l == oldl || l == null) { |
| return null; |
| } else if (l instanceof AppletEventMulticaster) { |
| return ((AppletEventMulticaster)l).remove(oldl); |
| } else { |
| return l; // it's not here |
| } |
| } |
| } |