Interval Operation - EPI

Add a closed interval

InsertInterval.java
  public static List<Interval> insertInterval(List<Interval> intervals,
                                              Interval newInterval) {
    int i = 0;
    List<Interval> result = new ArrayList<>();
    // Inserts intervals appeared before new_interval.
    while (i < intervals.size() && newInterval.left > intervals.get(i).right) {
      result.add(intervals.get(i++));
    }

    // Merges intervals that overlap with new_interval.
    while (i < intervals.size() && newInterval.right >= intervals.get(i).left) {
      newInterval = new Interval(Math.min(newInterval.left,
          intervals.get(i).left), Math.max(newInterval.right,
          intervals.get(i).right));
      ++i;
    }
    result.add(newInterval);

    // Inserts intervals appearing after new_interval.
    result.addAll(intervals.subList(i, intervals.size()));
    return result;
  }

Compute the union of intervals

UnionIntervals.java
  class Endpoint {
    public boolean isClose;
    public int val;
  }

  public int compareTo(ExInterval i) {
    if (left.val < i.left.val) {
      return -1;
    }
    if (left.val > i.left.val) {
      return 1;
    }
    if (left.isClose && !i.left.isClose) {
      return -1;
    }
    if (!left.isClose && i.left.isClose) {
      return 1;
    }
    return 0;
  }

  public Endpoint left = new Endpoint();
  public Endpoint right = new Endpoint();
}
  public static List<ExInterval> unionExIntervals(List<ExInterval> I) {

    // Empty input.
    List<ExInterval> uni = new ArrayList<>();
    if (I.isEmpty()) {
      return uni;
    }

    // Sorts ExIntervals according to their left endpoints.
    Collections.sort(I);
    ExInterval curr = new ExInterval();
    curr = I.get(0);

    for (int i = 1; i < I.size(); ++i) {
      if (I.get(i).left.val < curr.right.val
          || (I.get(i).left.val == curr.right.val
          && (I.get(i).left.isClose || curr.right.isClose))) {
        if (I.get(i).right.val > curr.right.val
            || (I.get(i).right.val == curr.right.val
            && I.get(i).right.isClose)) {
          curr.right = I.get(i).right;
        }
      } else {
        uni.add(curr);
        curr = I.get(i);
      }
    }
    uni.add(curr);
    return uni;
  }