1/*
2 * Copyright (C) 2015 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.tv.analytics;
18
19import android.os.SystemClock;
20
21/**
22 * Times a duration.
23 */
24public final class DurationTimer {
25    public static final long TIME_NOT_SET = -1;
26
27    private long startTimeMs = TIME_NOT_SET;
28
29    /**
30     * Returns true if the timer is running.
31     */
32    public boolean isRunning() {
33        return startTimeMs != TIME_NOT_SET;
34    }
35
36    /**
37     * Start the timer.
38     */
39    public void start() {
40        startTimeMs = SystemClock.elapsedRealtime();
41    }
42
43    /**
44     * Returns the current duration in milliseconds or {@link #TIME_NOT_SET} if the timer is not
45     * running.
46     */
47    public long getDuration() {
48        return isRunning() ? SystemClock.elapsedRealtime() - startTimeMs : TIME_NOT_SET;
49    }
50
51    /**
52     * Stops the timer and resets its value to {@link #TIME_NOT_SET}.
53     *
54     * @return the current duration in milliseconds or {@link #TIME_NOT_SET} if the timer is not
55     * running.
56     */
57    public long reset() {
58        long duration = getDuration();
59        startTimeMs = TIME_NOT_SET;
60        return duration;
61    }
62}
63