class SpanImpl extends DataPointImpl implements Span {

	@Override
	public <T extends Span> boolean extendsSpan(T span) {
		return span.intersection(this) != null && ((this.date.getMillis() < span.getDate().getMillis()) ||
				(this.nextDate.getMillis() > span.getNextDate().getMillis()));
	}

	public  SpanImpl(Period period, DateTime d, DateTime next);
	public  SpanImpl(SpanImpl other);

}