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      1 /*
      2  * Copyright (C) 2017 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.systemui.utils.os;
     18 
     19 import android.os.Handler;
     20 import android.os.Looper;
     21 import android.os.Message;
     22 
     23 import java.util.ArrayList;
     24 
     25 /**
     26  * A handler that allows control over when to dispatch messages and callbacks.
     27  *
     28  * WARNING: Because most Handler methods are final, the only thing this handler can intercept
     29  *          are sending messages and posting runnables, but *NOT* removing messages nor runnables.
     30  *          It also *CANNOT* intercept messages posted to the front of queue.
     31  */
     32 public class FakeHandler extends Handler {
     33 
     34     private Mode mMode = Mode.IMMEDIATE;
     35     private ArrayList<Message> mQueuedMessages = new ArrayList<>();
     36 
     37     public FakeHandler(Looper looper) {
     38         super(looper);
     39     }
     40 
     41     @Override
     42     public boolean sendMessageAtTime(Message msg, long uptimeMillis) {
     43         mQueuedMessages.add(msg);
     44         if (mMode == Mode.IMMEDIATE) {
     45             dispatchQueuedMessages();
     46         }
     47         return true;
     48     }
     49 
     50     public void setMode(Mode mode) {
     51         mMode = mode;
     52     }
     53 
     54     /**
     55      * Dispatch any messages that have been queued on the calling thread.
     56      */
     57     public void dispatchQueuedMessages() {
     58         ArrayList<Message> messages = new ArrayList<>(mQueuedMessages);
     59         mQueuedMessages.clear();
     60         for (Message msg : messages) {
     61             dispatchMessage(msg);
     62         }
     63     }
     64 
     65     public enum Mode {
     66         /** Messages are dispatched immediately on the calling thread. */
     67         IMMEDIATE,
     68         /** Messages are queued until {@link #dispatchQueuedMessages()} is called. */
     69         QUEUEING,
     70     }
     71 }
     72