LocalDateTimeRange2.java

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.stream.Collectors;

public class LocalDateTimeRange<T> {


    List<LocalDateTime> localDateTimes;

    private List<RangeWrap<T>> rangeWrapList;

    public LocalDateTimeRange() {
        localDateTimes = new ArrayList<>();
        rangeWrapList = new ArrayList<>();
    }


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


        localDateTimes.add(startedAt.plusSeconds(0));
        localDateTimes.add(endedAt.plusSeconds(0));
    }

    public Predicate<LocalDateTime> distinctByKey(Function<LocalDateTime, String> keyExtractor) {
        Map<Object, Boolean> map = new ConcurrentHashMap<>();
        return t -> map.putIfAbsent(keyExtractor.apply(t), Boolean.TRUE) == null;
    }


    public void show() {

        List<LocalDateTime> timeList = localDateTimes.stream()
                .filter(distinctByKey((Function<LocalDateTime, String>) (time) -> time.toString()))
                .sorted()
                .collect(Collectors.toList());
        ;



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


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

            System.out.println();
           final LocalDateTime current = timeList.get(i);
           final LocalDateTime next = timeList.get(i+1);

            System.out.println("current : " + current);
            System.out.println("next : " + next);

            LocalDateTime checkedCurrent = current.plusSeconds(0);
            LocalDateTime checkedNext = next.plusSeconds(0);


            boolean currentIsSomeStart = rangeWrapList.stream().filter(rw -> {
                        if (current.compareTo(rw.startedAt) != 0) {
                            return true;
                        }
                        return false;
                    }).findFirst().isPresent();

            if(!currentIsSomeStart) {
                checkedCurrent = current.plusSeconds(1);
            }

            boolean nextIsSomeEnd = rangeWrapList.stream().filter(rw -> {
                if (current.compareTo(rw.endedAt) != 0) {
                    return true;
                }
                return false;
            }).findFirst().isPresent();
            if(!nextIsSomeEnd) {
                checkedNext = next.minusSeconds(1);
            }

            System.out.println("checkedCurrent : " + checkedCurrent);
            System.out.println("checkedNext : " + checkedNext);

            RangeWrapResult r = new RangeWrapResult(checkedCurrent, checkedNext , new ArrayList<>());

            List<T> wrapList = rangeWrapList.stream().filter(rw -> {

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

                    r.wrapObjList = wrapList;

                    rangeWrapResults.add(r);



        }


        rangeWrapResults.stream()
                .filter(r-> (r.wrapObjList != null && !r.wrapObjList.isEmpty()))
                .forEach(r -> {
                    System.out.println(r.startedAt + " ~ " + r.endedAt + "  " + r.wrapObjList);
                });




    }


    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;
        }

    }


    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 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"));
        System.out.println(as);
        LocalDateTime ae = LocalDateTime.parse("2019-03-02 14:59:59", DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
        System.out.println(ae);

        LocalDateTime bs = LocalDateTime.parse("2019-03-03 15:00:00", DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
        System.out.println(bs);
        LocalDateTime be = LocalDateTime.parse("2019-03-07 14:59:59", DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
        System.out.println(be);

        LocalDateTime cs = LocalDateTime.parse("2019-03-05 15:00:00", DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
        System.out.println(cs);
        LocalDateTime ce = LocalDateTime.parse("2019-03-07 14:59:59", DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
        System.out.println(ce);

        LocalDateTimeRange<String> a = new LocalDateTimeRange<>();

        a.add(as, ae, "1");
        a.add(bs, be, "2");
        a.add(cs, ce, "3");
        System.out.println();
        System.out.println();
        a.show();


    }


}