给定两个日期范围列表，如何在java中查找非重叠日期

Question

我不确定我的标题是否正确，但这正是我想要实现的目标。 考虑以下两个类，AbsentPeriod，UnavailablePeriod。

class AbsentPeriod
{
    Date startDate;
    Date endDate;
}

class UnavailablePeriod
{
    Date startDate;
    Date endDate;
}

特定

Date StartDate // starting point
Date EndDate //ending point
List<AbsentPeriod> absentperiods
List<UnavailablePeriods> unavailablePeriods

找

List<AvailablePeriod> 

具有日期的开始日期和结束日期与不存在和不可用期间的日期不重叠; 在给定的StartDate和endDate之间

class AvailablePeriod
{
   Date startDate;
   Date endDate;
}

Answer 1

您可以遍历AbsentPeriod和UnavailablePeriod列表，使用以下函数检查日期是否重叠，如果没有，则将其添加到结果列表：

public static boolean dateRangeOverlap(Date givenStartDate, Date givenEndDate, Date listItemStartDate, Date listItemEndDate)
{
    boolean result = false;
    if (givenStartDate !=null && givenEndDate !=null && listItemStartDate !=null && listItemEndDate != null){
        result = (givenStartDate.getTime() <= listItemEndDate.getTime()) && (givenEndDate.getTime() >= listItemStartDate.getTime()); 
    }
    return result;
}

Answer 2

如果我的理解是：你试图找出所有可用的时期，当有一些缺席的时期列表

然后有一个完整的解决方案，当有很多缺席期间列表时解决：

public class Extra_1_interval_merge {
    @Test
    public void testAvailablePeriod() {
        List<MyPeriod> absentPeriods0 = new ArrayList<>();
        absentPeriods0.add(makePeriod(LocalDate.now(), LocalDate.now().plusDays(1), PeriodType.ABSENT));
        absentPeriods0.add(makePeriod(LocalDate.now().plusDays(4), LocalDate.now().plusDays(6), PeriodType.ABSENT));
        absentPeriods0.add(makePeriod(LocalDate.now().plusDays(2), LocalDate.now().plusDays(3), PeriodType.ABSENT));


        List<MyPeriod> absentPeriods1 = new ArrayList<>();
        absentPeriods1.add(makePeriod(LocalDate.now(), LocalDate.now().plusDays(2), PeriodType.UNAVAILABLE));
        absentPeriods1.add(makePeriod(LocalDate.now().plusDays(5), LocalDate.now().plusDays(7), PeriodType.UNAVAILABLE));

        List<List<MyPeriod>> absentListList = new ArrayList<>();
        absentListList.add(absentPeriods0);
        absentListList.add(absentPeriods1);
        System.out.println(getAvailablePeriods(absentListList));
    }

    private List<MyPeriod> getAvailablePeriods(List<List<MyPeriod>> absentListList) {
        // Step - 1: Collect all periods;
        List<MyPeriod> tempList = new ArrayList<>();
        absentListList.stream().forEach(list -> tempList.addAll(list));

        // Step - 2: Sort the periods based on the startDate and then endDate;
        List<MyPeriod> absentList = tempList.stream().sorted((period1, period2) -> {
            if (!period1.startDate.isEqual(period2.startDate)) {
                return period1.startDate.compareTo(period2.startDate);
            } else {
                return period1.endDate.compareTo(period2.endDate);
            }
        }).collect(toList());

        // Step - 3: Merge all overlapped periods to form an one-dimension occupied period list;
        List<MyPeriod> mergedPeriods = new ArrayList<>();
        for (MyPeriod period : absentList) {
            if (mergedPeriods.isEmpty()) {
                mergedPeriods.add(period);
            } else {
                MyPeriod lastPeriod = mergedPeriods.get(mergedPeriods.size() - 1);
                if (!lastPeriod.endDate.isBefore(period.startDate)) {
                    if (lastPeriod.endDate.isBefore(period.endDate)) {
                        lastPeriod.endDate = period.endDate;
                    }
                } else {
                    mergedPeriods.add(period);
                }
            }
        }

        // Step - 4: Pick the periods from the occupied period list;
        List<MyPeriod> availablePeriods = new ArrayList<>();
        for (int i = 0, len = mergedPeriods.size(); i < len - 1; i++) {
            availablePeriods.add(makePeriod(mergedPeriods.get(i).endDate, mergedPeriods.get(i + 1).startDate, PeriodType.AVAILABLE));
        }
        return availablePeriods;
    }

    private MyPeriod makePeriod(LocalDate startDate, LocalDate endDate, PeriodType periodType) {
        MyPeriod thePeriod = null;
        switch (periodType) {
            case ABSENT:
                thePeriod = new AbsentPeriod();
                break;
            case UNAVAILABLE:
                thePeriod = new UnavailablePeriod();
                break;
            case AVAILABLE:
                thePeriod = new AvailablePeriod();
                break;
            default:
                thePeriod = new MyPeriod();
                break;
        }
        thePeriod.startDate = startDate;
        thePeriod.endDate = endDate;
        return thePeriod;
    }

    enum PeriodType {
        ABSENT,
        UNAVAILABLE,
        AVAILABLE;
    }

    class MyPeriod {
        LocalDate startDate;
        LocalDate endDate;

        @Override
        public String toString() {
            return String.format("Start: %s, End: %s", startDate, endDate);
        }
    }

    class AbsentPeriod extends MyPeriod {
    }

    class UnavailablePeriod extends MyPeriod {
    }

    class AvailablePeriod extends MyPeriod {
    }

}

输入：

• 缺席期间清单 - 1：[0,1]，[4,6]，[2,3]
• 缺席期间清单 - 2：[0,2]，[5,7]

最终结果将是：

• 可用期限清单：[3,4]

如果需要，您可以尝试更多缺席期间列表。

更新

我不知道为什么OP需要三种不同类型的Period/Interval 。 但为了解决具体问题，我根据OP的需求更新了解决方案。

正如其他评论所指出的，为什么有三种不同的类型？ 我没有任何线索...