code: public Range intersection(final Range range) {
  		int c0 = Math.max(this.start, range.start);
  		int c1 = Math.min(this.end, range.end);
  		return c0 <= c1 ? new Range(c0, c1) : null;
  	}
docs: 共通部分を取り出す
  
  @param range 判定Range
  @return {@link Range} 共通部が無い場合はnull