@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		Period other = (Period) obj;
		if (cost != other.cost)
			return false;
		if (date_hour == null) {
			if (other.date_hour != null)
				return false;
		} else if (!date_hour.equals(other.date_hour))
			return false;
		if (duration != other.duration)
			return false;
		if (id != other.id)
			return false;
		return true;
	}