Java Data Type How to - Get the next or same closest date from the specified days in daysOfWeek List at specified hour and min

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Question

We would like to know how to get the next or same closest date from the specified days in daysOfWeek List at specified hour and min.

Answer

   /*from ww w  . jav  a2  s.com*/
import java.time.DayOfWeek;
import java.time.LocalDateTime;
import java.time.temporal.TemporalAdjusters;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;

public class Main {
  public static void main(String[] argv) {
    DayOfWeek d = DayOfWeek.FRIDAY;
    List<DayOfWeek> l = new ArrayList<>();
    l.add(d);
    
    System.out.println(getNextClosestDateTime(l,22,20));
  }

  /**
   * Gets the next or same closest date from the specified days in
   * {@code daysOfWeek List} at specified {@code hour} and {@code min}.
   * 
   * @param daysOfWeek
   *          the days of week
   * @param hour
   *          the hour
   * @param min
   *          the min
   * @return the next or same date from the days of week at specified time
   * @throws IllegalArgumentException
   *           if the {@code daysOfWeek List} is empty.
   */
  public static LocalDateTime getNextClosestDateTime(
      List<DayOfWeek> daysOfWeek, int hour, int min)
      throws IllegalArgumentException {
    if (daysOfWeek.isEmpty()) {
      throw new IllegalArgumentException("daysOfWeek should not be empty.");
    }

    final LocalDateTime dateNow = LocalDateTime.now();
    final LocalDateTime dateNowWithDifferentTime = dateNow.withHour(hour)
        .withMinute(min).withSecond(0);

    // @formatter:off
    return daysOfWeek
        .stream()
        .map(
            d -> dateNowWithDifferentTime.with(TemporalAdjusters.nextOrSame(d)))
        .filter(d -> d.isAfter(dateNow))
        .min(Comparator.naturalOrder())
        .orElse(
            dateNowWithDifferentTime.with(TemporalAdjusters.next(daysOfWeek
                .get(0))));
    // @formatter:on
  }
}

/*
 * Copyright (C) 2004-2015 L2J Server
 * 
 * This file is part of L2J Server.
 * 
 * L2J Server is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * L2J Server is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

The code above generates the following result.

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