1 /*
   2  * Copyright (c) 2008, 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 
  26 package sun.awt;
  27 
  28 import java.awt.AWTEvent;
  29 import java.awt.EventQueue;
  30 
  31 
  32 public class EventQueueDelegate {
  33     private static final Object EVENT_QUEUE_DELEGATE_KEY =
  34         new StringBuilder("EventQueueDelegate.Delegate");
  35 
  36     public static void setDelegate(Delegate delegate) {
  37         AppContext.getAppContext().put(EVENT_QUEUE_DELEGATE_KEY, delegate);
  38     }
  39     public static Delegate getDelegate() {
  40         return
  41           (Delegate) AppContext.getAppContext().get(EVENT_QUEUE_DELEGATE_KEY);
  42     }
  43     public interface Delegate {
  44         /**
  45          * This method allows for changing {@code EventQueue} events order.
  46          *
  47          * @param eventQueue current {@code EventQueue}
  48          * @return next {@code event} for the {@code EventDispatchThread}
  49          */
  50 
  51         public AWTEvent getNextEvent(EventQueue eventQueue) throws InterruptedException;
  52 
  53         /**
  54          * Notifies delegate before EventQueue.dispatch method.
  55          *
  56          * Note: this method may mutate the event
  57          *
  58          * @param event  to be dispatched by {@code dispatch} method
  59          * @return handle to be passed to {@code afterDispatch} method
  60          */
  61         public Object beforeDispatch(AWTEvent event) throws InterruptedException;
  62 
  63         /**
  64          * Notifies delegate after EventQueue.dispatch method.
  65          *
  66          * @param event {@code event} dispatched by the {@code dispatch} method
  67          * @param handle object which came from {@code beforeDispatch} method
  68          */
  69         public void afterDispatch(AWTEvent event, Object handle) throws InterruptedException;
  70     }
  71 }