Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.util.concurrent.TimeUnit;

public class Main {
    public static final long DAY_IN_MILLIS = TimeUnit.DAYS.toMillis(1);

    /**
     * Normalizes a date (in milliseconds).
     *
     * Normalize, in our usage within Sunshine means to convert a given date in milliseconds to
     * the very beginning of the date in UTC time.
     *
     *   For example, given the time representing
     *
     *     Friday, 9/16/2016, 17:45:15 GMT-4:00 DST (1474062315000)
     *
     *   this method would return the number of milliseconds (since the epoch) that represents
     *
     *     Friday, 9/16/2016, 00:00:00 GMT (1473984000000)
     *
     * To make it easy to query for the exact date, we normalize all dates that go into
     * the database to the start of the day in UTC time. In order to normalize the date, we take
     * advantage of simple integer division, noting that any remainder is discarded when dividing
     * two integers.
     *
     *     For example, dividing 7 / 3 (when using integer division) equals 2, not 2.333 repeating
     *   as you may expect.
     *
     * @param date The date (in milliseconds) to normalize
     *
     * @return The UTC date at 12 midnight of the date
     */
    public static long normalizeDate(long date) {
        long daysSinceEpoch = elapsedDaysSinceEpoch(date);
        long millisFromEpochToTodayAtMidnightUtc = daysSinceEpoch * DAY_IN_MILLIS;
        return millisFromEpochToTodayAtMidnightUtc;
    }

    /**
     * This method returns the number of days since the epoch (January 01, 1970, 12:00 Midnight UTC)
     * in UTC time from the current date.
     *
     * @param utcDate A date in milliseconds in UTC time.
     *
     * @return The number of days from the epoch to the date argument.
     */
    private static long elapsedDaysSinceEpoch(long utcDate) {
        return TimeUnit.MILLISECONDS.toDays(utcDate);
    }
}