src/main/java/io/mifos/core/lang/DateRange.java

/*
 * Copyright 2018 The Apache Software Foundation
 *
 * 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 io.mifos.core.lang;

import org.springframework.util.Assert;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.time.Clock;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.format.DateTimeParseException;
import java.time.temporal.ChronoUnit;
import java.util.stream.Stream;

/**
 * A range of dates specified by a start and an end.  Inclusive of both.
 *
 * @author Myrle Krantz
 */
@SuppressWarnings("WeakerAccess")
public class DateRange {
  private final @Nonnull LocalDate start;
  private final @Nonnull LocalDate end;

  public DateRange(final @Nonnull LocalDate start, final @Nonnull LocalDate end) {
    Assert.notNull(start, "Range start must be given.");
    Assert.notNull(start, "Range end must be given.");
    this.start = start;
    this.end = end;
  }

  public Stream<LocalDate> stream() {
    return Stream.iterate(start, (current) -> current.plusDays(1))
        .limit(ChronoUnit.DAYS.between(start, end) + 1);
  }

  public LocalDateTime getStartDateTime() {
    return start.atStartOfDay();
  }

  public LocalDateTime getEndDateTime() {
    return end.plusDays(1).atStartOfDay();
  }

  @Override
  public String toString() {
    return DateConverter.toIsoString(start) + ".." + DateConverter.toIsoString(end);
  }

  @Nonnull
  public static DateRange fromIsoString(@Nullable final String isoDateRangeString) {
    if (isoDateRangeString == null) {
      final LocalDate today = LocalDate.now(Clock.systemUTC());
      return new DateRange(today, today);
    } else {
      final String[] dates = isoDateRangeString.split("\\.\\.");
      if (dates.length != 2)
        throw ServiceException.badRequest("Date range should consist of exactly two dates.",
            isoDateRangeString);

      try {
        return new DateRange(DateConverter.dateFromIsoString(dates[0]), DateConverter.dateFromIsoString(dates[1]));
      }
      catch(final DateTimeParseException e){
        throw ServiceException.badRequest("Date {0} must use ISO format",
            isoDateRangeString);
      }
    }
  }
}