google.registry.model.common.TimeOfYear.java Source code

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Here is the source code for google.registry.model.common.TimeOfYear.java

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// Copyright 2016 The Nomulus Authors. All Rights Reserved.
//
// 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.

package google.registry.model.common;

import static com.google.common.collect.DiscreteDomain.integers;
import static google.registry.util.DateTimeUtils.END_OF_TIME;
import static google.registry.util.DateTimeUtils.START_OF_TIME;
import static google.registry.util.DateTimeUtils.isAtOrAfter;
import static google.registry.util.DateTimeUtils.isBeforeOrAt;
import static org.joda.time.DateTimeZone.UTC;

import com.google.common.base.Function;
import com.google.common.base.Splitter;
import com.google.common.collect.ContiguousSet;
import com.google.common.collect.FluentIterable;
import com.google.common.collect.Range;
import com.googlecode.objectify.annotation.Embed;
import com.googlecode.objectify.annotation.Index;
import google.registry.model.ImmutableObject;
import java.util.List;
import org.joda.time.DateTime;

/**
 * A time of year (month, day, millis of day) that can be stored in a sort-friendly format.
 *
 * <p>This is conceptually similar to {@code MonthDay} in Joda or more generally to Joda's
 * {@code Partial}, but the parts we need are too simple to justify a full implementation of
 * {@code Partial}.
 *
 * <p>For simplicity, the native representation of this class's data is its stored format. This
 * allows it to be embeddable with no translation needed and also delays parsing of the string on
 * load until it's actually needed.
 */
@Embed
public class TimeOfYear extends ImmutableObject {

    /**
     * The time as "month day millis" with all fields left-padded with zeroes so that lexographic
     * sorting will do the right thing.
     */
    @Index
    String timeString;

    /**
     * Constructs a {@link TimeOfYear} from a {@link DateTime}.
     *
     * <p>This handles leap years in an intentionally peculiar way by always treating February 29 as
     * February 28. It is impossible to construct a {@link TimeOfYear} for February 29th.
     */
    public static TimeOfYear fromDateTime(DateTime dateTime) {
        DateTime nextYear = dateTime.plusYears(1); // This turns February 29 into February 28.
        TimeOfYear instance = new TimeOfYear();
        instance.timeString = String.format("%02d %02d %08d", nextYear.getMonthOfYear(), nextYear.getDayOfMonth(),
                nextYear.getMillisOfDay());
        return instance;
    }

    /**
     * Returns an {@link Iterable} of {@link DateTime}s of every recurrence of this particular
     * time of year within a given {@link Range} (usually one spanning many years).
     *
     * <p>WARNING: This can return a potentially very large {@link Iterable} if {@code END_OF_TIME}
     * is used as the upper endpoint of the range.
     */
    public Iterable<DateTime> getInstancesInRange(Range<DateTime> range) {
        // In registry world, all dates are within START_OF_TIME and END_OF_TIME, so restrict any
        // ranges without bounds to our notion of zero-to-infinity.
        Range<DateTime> normalizedRange = range.intersection(Range.closed(START_OF_TIME, END_OF_TIME));
        Range<Integer> yearRange = Range.closed(normalizedRange.lowerEndpoint().getYear(),
                normalizedRange.upperEndpoint().getYear());
        return FluentIterable.from(ContiguousSet.create(yearRange, integers()))
                .transform(new Function<Integer, DateTime>() {
                    @Override
                    public DateTime apply(Integer year) {
                        return getDateTimeWithYear(year);
                    }
                }).filter(normalizedRange);
    }

    /** Get the first {@link DateTime} with this month/day/millis that is at or after the start. */
    public DateTime getNextInstanceAtOrAfter(DateTime start) {
        DateTime withSameYear = getDateTimeWithYear(start.getYear());
        return isAtOrAfter(withSameYear, start) ? withSameYear : withSameYear.plusYears(1);
    }

    /** Get the first {@link DateTime} with this month/day/millis that is at or before the end. */
    public DateTime getLastInstanceBeforeOrAt(DateTime end) {
        DateTime withSameYear = getDateTimeWithYear(end.getYear());
        return isBeforeOrAt(withSameYear, end) ? withSameYear : withSameYear.minusYears(1);
    }

    /**
     * Return a new datetime with the same year as the parameter but projected to the month, day, and
     * time of day of this object.
     */
    private DateTime getDateTimeWithYear(int year) {
        List<String> monthDayMillis = Splitter.on(' ').splitToList(timeString);
        // Do not be clever and use Ints.stringConverter here. That does radix guessing, and bad things
        // will happen because of the leading zeroes.
        return new DateTime(0, UTC).withYear(year).withMonthOfYear(Integer.parseInt(monthDayMillis.get(0)))
                .withDayOfMonth(Integer.parseInt(monthDayMillis.get(1)))
                .withMillisOfDay(Integer.parseInt(monthDayMillis.get(2)));
    }
}