1 /*
2  * Copyright (C) 2014 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.ex.camera2.portability;
18 
19 import android.os.Handler;
20 import android.os.Looper;
21 import android.os.Message;
22 
23 import java.util.LinkedList;
24 
25 class HistoryHandler extends Handler {
26     private static final int MAX_HISTORY_SIZE = 400;
27 
28     final LinkedList<Integer> mMsgHistory;
29 
HistoryHandler(Looper looper)30     HistoryHandler(Looper looper) {
31         super(looper);
32         mMsgHistory = new LinkedList<Integer>();
33         // We add a -1 at the beginning to mark the very beginning of the
34         // history.
35         mMsgHistory.offerLast(-1);
36     }
37 
getCurrentMessage()38     Integer getCurrentMessage() {
39         return mMsgHistory.peekLast();
40     }
41 
generateHistoryString(int cameraId)42     String generateHistoryString(int cameraId) {
43         String info = new String("HIST");
44         info += "_ID" + cameraId;
45         for (Integer msg : mMsgHistory) {
46             info = info + '_' + msg.toString();
47         }
48         info += "_HEND";
49         return info;
50     }
51 
52     /**
53      * Subclasses' implementations should call this one before doing their work.
54      */
55     @Override
handleMessage(Message msg)56     public void handleMessage(Message msg) {
57         mMsgHistory.offerLast(msg.what);
58         while (mMsgHistory.size() > MAX_HISTORY_SIZE) {
59             mMsgHistory.pollFirst();
60         }
61     }
62 }
63