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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.server.accessibility;
     18 
     19 import android.app.Notification;
     20 import android.os.Handler;
     21 import android.os.Message;
     22 import android.util.Pair;
     23 
     24 import java.util.ArrayList;
     25 import java.util.List;
     26 
     27 /**
     28  * Utility class to capture messages dispatched through a handler and control when they arrive
     29  * at their target.
     30  */
     31 public class MessageCapturingHandler extends Handler {
     32     List<Pair<Message, Long>> timedMessages = new ArrayList<>();
     33 
     34     Handler.Callback mCallback;
     35 
     36     public MessageCapturingHandler(Handler.Callback callback) {
     37         mCallback = callback;
     38     }
     39 
     40     @Override
     41     public boolean sendMessageAtTime(Message message, long uptimeMillis) {
     42         timedMessages.add(new Pair<>(Message.obtain(message), uptimeMillis));
     43         return super.sendMessageAtTime(message, uptimeMillis);
     44     }
     45 
     46     public void setCallback(Handler.Callback callback) {
     47         mCallback = callback;
     48     }
     49 
     50     public void sendOneMessage() {
     51         Message message = timedMessages.remove(0).first;
     52         removeMessages(message.what, message.obj);
     53         dispatchMessage(message);
     54         removeStaleMessages();
     55     }
     56 
     57     public void sendAllMessages() {
     58         while (!timedMessages.isEmpty()) {
     59             sendOneMessage();
     60         }
     61     }
     62 
     63     public void sendLastMessage() {
     64         Message message = timedMessages.remove(timedMessages.size() - 1).first;
     65         removeMessages(message.what, message.obj);
     66         dispatchMessage(message);
     67         removeStaleMessages();
     68     }
     69 
     70     public boolean hasMessages() {
     71         removeStaleMessages();
     72         return !timedMessages.isEmpty();
     73     }
     74 
     75     private void removeStaleMessages() {
     76         for (int i = 0; i < timedMessages.size(); i++) {
     77             Message message = timedMessages.get(i).first;
     78             if (!hasMessages(message.what, message.obj)) {
     79                 timedMessages.remove(i--);
     80             }
     81         }
     82     }
     83 
     84     public void dispatchMessage(Message m) {
     85         if (mCallback != null) {
     86             mCallback.handleMessage(m);
     87             return;
     88         }
     89         super.dispatchMessage(m);
     90     }
     91 }
     92