LocalDateTimeRange.java

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.*;
import java.util.stream.Collectors;

public class LocalDateTimeRange<T> {


    enum EDGE {
        START, END
    }


    Map<LocalDateTime, Set<EDGE>> localDateTimesMap = new HashMap<>();

    private Set<RangeWrap<T>> rangeWrapList = new HashSet<>();

    public LocalDateTimeRange() {

    }


    public void add(RangeWrap<T> rangeWrap) {
        rangeWrapList.add(rangeWrap);

        LocalDateTime startedAtKey = rangeWrap.getStartedAt().plusSeconds(0);
        localDateTimesMap.computeIfAbsent(startedAtKey, (key) -> new HashSet<>()).add(EDGE.START);

        LocalDateTime endedAtKey = rangeWrap.getEndedAt().plusSeconds(0);
        localDateTimesMap.computeIfAbsent(endedAtKey, (key) -> new HashSet<>()).add(EDGE.END);
    }

    public void add(LocalDateTime startedAt, LocalDateTime endedAt, T wrapObj) {
        this.add(new RangeWrap<T>(startedAt, endedAt, wrapObj));
    }


    public List<RangeWrapResult> getResults() {

        List<RangeWrapResult> rangeWrapResults = new ArrayList<>();

        List<LocalDateTime> timeKeyList = localDateTimesMap.keySet().stream()
                .sorted()
                .collect(Collectors.toList());


        for (int i = 0; i < timeKeyList.size() - 1; i++) {

            LocalDateTime from = timeKeyList.get(i);
            LocalDateTime to = timeKeyList.get(i + 1);

            // 시작일이 아닐 경우 기간 분리를 위해 1초 +
            if (!localDateTimesMap.get(from).contains(EDGE.START)) {
                from = from.plusSeconds(1);
            }

            // 종료일이 아닐경우 기간 분리를 위해 1초 -
            if (!localDateTimesMap.get(to).contains(EDGE.END)) {
                to = to.minusSeconds(1);
            }

            // lambda 참조를 위한 final 선언
            final LocalDateTime checkedFrom = from;
            final LocalDateTime checkedTo = to;

            // 기간분리시 종료~시작 케이스 , 역순 기간은 제외
            if (from.compareTo(to) < 0) {

                // 기간에 포함되는 obj list
                List<T> wrapObjList = rangeWrapList.stream()
                        .filter(wrapItem -> {

                            if (checkedFrom.compareTo(wrapItem.startedAt) >= 0 && checkedTo.compareTo(wrapItem.endedAt) <= 0) {
                                return true;
                            }
                            return false;
                        })
                        .map(wrapItem -> wrapItem.wrapObj)
                        .collect(Collectors.toList());

                // 기가엔 포함되는 obj가 없을경우 결과 제외
                if(!wrapObjList.isEmpty()) {
                    RangeWrapResult result = new RangeWrapResult(checkedFrom, checkedTo, wrapObjList);
                    rangeWrapResults.add(result);
                }
            }

        }
        return rangeWrapResults;
    }


    @SuppressWarnings("hiding")
    class RangeWrap<T> {

        private LocalDateTime startedAt;
        private LocalDateTime endedAt;
        private T wrapObj;

        public RangeWrap(LocalDateTime startedAt, LocalDateTime endedAt, T wrapObj) {
            this.startedAt = startedAt;
            this.endedAt = endedAt;
            this.wrapObj = wrapObj;
        }

        public LocalDateTime getStartedAt() {
            return startedAt;
        }

        public void setStartedAt(LocalDateTime startedAt) {
            this.startedAt = startedAt;
        }

        public LocalDateTime getEndedAt() {
            return endedAt;
        }

        public void setEndedAt(LocalDateTime endedAt) {
            this.endedAt = endedAt;
        }

        public T getWrapObj() {
            return wrapObj;
        }

        public void setWrapObj(T wrapObj) {
            this.wrapObj = wrapObj;
        }

        @Override
        public String toString() {
            return "RangeWrap [startedAt=" + startedAt + ", endedAt=" + endedAt + ", wrapObj=" + wrapObj + "]";
        }


    }


    class RangeWrapResult {

        private LocalDateTime startedAt;
        private LocalDateTime endedAt;
        private List<T> wrapObjList;

        public RangeWrapResult(LocalDateTime startedAt, LocalDateTime endedAt, List<T> wrapObjList) {
            this.startedAt = startedAt;
            this.endedAt = endedAt;
            this.wrapObjList = wrapObjList;
        }

        public LocalDateTime getStartedAt() {
            return startedAt;
        }

        public void setStartedAt(LocalDateTime startedAt) {
            this.startedAt = startedAt;
        }

        public LocalDateTime getEndedAt() {
            return endedAt;
        }

        public void setEndedAt(LocalDateTime endedAt) {
            this.endedAt = endedAt;
        }

        public List<T> getWrapObjList() {
            return wrapObjList;
        }

        public void setWrapObjList(List<T> wrapObjList) {
            this.wrapObjList = wrapObjList;
        }

        @Override
        public String toString() {
            return "RangeWrapResult [startedAt=" + startedAt + ", endedAt=" + endedAt + ", wrapObjList=" + wrapObjList + "]";
        }

    }


    public static void main(String... args) {


        LocalDateTime now = LocalDateTime.now();


        LocalDateTime as = LocalDateTime.parse("2019-03-01 15:00:00", DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
        LocalDateTime ae = LocalDateTime.parse("2019-03-10 14:59:59", DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));

        LocalDateTime bs = LocalDateTime.parse("2019-03-02 15:00:00", DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
        LocalDateTime be = LocalDateTime.parse("2019-03-13 14:59:59", DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));

        LocalDateTime cs = LocalDateTime.parse("2019-03-08 15:00:00", DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
        LocalDateTime ce = LocalDateTime.parse("2019-03-15 14:59:59", DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
        LocalDateTimeRange<String> a = new LocalDateTimeRange<>();

        LocalDateTimeRange<String>.RangeWrap<String> rw1 = a.new RangeWrap<>(as, ae, "1");
        System.out.println(rw1);
        LocalDateTimeRange<String>.RangeWrap<String> rw2 = a.new RangeWrap<>(bs, be, "2");
        System.out.println(rw2);
        LocalDateTimeRange<String>.RangeWrap<String> rw3 = a.new RangeWrap<>(cs, ce, "3");
        System.out.println(rw3);
        
        a.add(rw1);
        a.add(rw2);
        a.add(rw3);

        a.getResults().stream().forEach(wrap -> {
            System.out.println(wrap.getStartedAt() + " ~ " + wrap.getEndedAt() + " : " + wrap.getWrapObjList());
        });

    }
}