1 /*
2  * Copyright (C) 2012 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.contacts.common.util;
18 
19 import android.util.Log;
20 
21 import com.google.common.collect.Lists;
22 
23 import java.util.ArrayList;
24 
25 /**
26  * A {@link StopWatch} records start, laps and stop, and print them to logcat.
27  */
28 public class StopWatch {
29 
30     private final String mLabel;
31 
32     private final ArrayList<Long> mTimes = Lists.newArrayList();
33     private final ArrayList<String> mLapLabels = Lists.newArrayList();
34 
StopWatch(String label)35     private StopWatch(String label) {
36         mLabel = label;
37         lap("");
38     }
39 
40     /**
41      * Create a new instance and start it.
42      */
start(String label)43     public static StopWatch start(String label) {
44         return new StopWatch(label);
45     }
46 
47     /**
48      * Record a lap.
49      */
lap(String lapLabel)50     public void lap(String lapLabel) {
51         mTimes.add(System.currentTimeMillis());
52         mLapLabels.add(lapLabel);
53     }
54 
55     /**
56      * Stop it and log the result, if the total time >= {@code timeThresholdToLog}.
57      */
stopAndLog(String TAG, int timeThresholdToLog)58     public void stopAndLog(String TAG, int timeThresholdToLog) {
59 
60         lap("");
61 
62         final long start = mTimes.get(0);
63         final long stop = mTimes.get(mTimes.size() - 1);
64 
65         final long total = stop - start;
66         if (total < timeThresholdToLog) return;
67 
68         final StringBuilder sb = new StringBuilder();
69         sb.append(mLabel);
70         sb.append(",");
71         sb.append(total);
72         sb.append(": ");
73 
74         long last = start;
75         for (int i = 1; i < mTimes.size(); i++) {
76             final long current = mTimes.get(i);
77             sb.append(mLapLabels.get(i));
78             sb.append(",");
79             sb.append((current - last));
80             sb.append(" ");
81             last = current;
82         }
83         Log.v(TAG, sb.toString());
84     }
85 
86     /**
87      * Return a dummy instance that does no operations.
88      */
getNullStopWatch()89     public static StopWatch getNullStopWatch() {
90         return NullStopWatch.INSTANCE;
91     }
92 
93     private static class NullStopWatch extends StopWatch {
94         public static final NullStopWatch INSTANCE = new NullStopWatch();
95 
NullStopWatch()96         public NullStopWatch() {
97             super(null);
98         }
99 
100         @Override
lap(String lapLabel)101         public void lap(String lapLabel) {
102             // noop
103         }
104 
105         @Override
stopAndLog(String TAG, int timeThresholdToLog)106         public void stopAndLog(String TAG, int timeThresholdToLog) {
107             // noop
108         }
109     }
110 }
111