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 android.net.util;
18 
19 import android.os.SystemClock;
20 
21 
22 /**
23  * @hide
24  */
25 public class Stopwatch {
26     private long mStartTimeNs;
27     private long mStopTimeNs;
28 
isStarted()29     public boolean isStarted() {
30         return (mStartTimeNs > 0);
31     }
32 
isStopped()33     public boolean isStopped() {
34         return (mStopTimeNs > 0);
35     }
36 
isRunning()37     public boolean isRunning() {
38         return (isStarted() && !isStopped());
39     }
40 
41     /**
42      * Start the Stopwatch.
43      */
start()44     public Stopwatch start() {
45         if (!isStarted()) {
46             mStartTimeNs = SystemClock.elapsedRealtimeNanos();
47         }
48         return this;
49     }
50 
51     /**
52      * Restart the Stopwatch.
53      */
restart()54     public Stopwatch restart() {
55         mStartTimeNs = SystemClock.elapsedRealtimeNanos();
56         mStopTimeNs = 0;
57         return this;
58     }
59 
60     /**
61      * Stop the Stopwatch.
62      * @return the total time recorded, in microseconds, or 0 if not started.
63      */
stop()64     public long stop() {
65         if (isRunning()) {
66             mStopTimeNs = SystemClock.elapsedRealtimeNanos();
67         }
68         // Return either the delta after having stopped, or 0.
69         return (mStopTimeNs - mStartTimeNs) / 1000;
70     }
71 
72     /**
73      * Return the total time recorded to date, in microseconds.
74      * If the Stopwatch is not running, returns the same value as stop(),
75      * i.e. either the total time recorded before stopping or 0.
76      */
lap()77     public long lap() {
78         if (isRunning()) {
79             return (SystemClock.elapsedRealtimeNanos() - mStartTimeNs) / 1000;
80         } else {
81             return stop();
82         }
83     }
84 
85     /**
86      * Reset the Stopwatch. It will be stopped when this method returns.
87      */
reset()88     public void reset() {
89         mStartTimeNs = 0;
90         mStopTimeNs = 0;
91     }
92 }
93