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
17package com.android.contacts.common.util;
18
19import android.util.Log;
20
21import com.google.common.collect.Lists;
22
23import java.util.ArrayList;
24
25/**
26 * A {@link StopWatch} records start, laps and stop, and print them to logcat.
27 */
28public 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
35    private StopWatch(String label) {
36        mLabel = label;
37        lap("");
38    }
39
40    /**
41     * Create a new instance and start it.
42     */
43    public static StopWatch start(String label) {
44        return new StopWatch(label);
45    }
46
47    /**
48     * Record a lap.
49     */
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     */
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     */
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
96        public NullStopWatch() {
97            super(null);
98        }
99
100        @Override
101        public void lap(String lapLabel) {
102            // noop
103        }
104
105        @Override
106        public void stopAndLog(String TAG, int timeThresholdToLog) {
107            // noop
108        }
109    }
110}
111