How to define a class that represents an age group? - date-range

Question

I need to be able to define various age groups, i.e. 10 - 11, 12 - 13, etc.
How can I represent an AgeGroup class such that that the age can appropriately group people together today, tomorrow, and in the future, i.e. today's 11 year old could 12 tomorrow (in which case he would be grouped into the 12-13 group instead of the 10-11 year old group, as he was yesterday).
So far I have this:
public class AgeGroup
{
public string Name { get; protected set; }
public DateRange BirthDateRange { get; protected set; }
public Guid Id { get; protected set; }
public Status Status { get; protected set; }
public virtual DateRange ApplicableDateRange { get; set; }
public AgeGroup(Guid id, string name, DateRange birthDateRange,DateRange applicableDateRange)
{
Id = id;
Name = name;
Status = status;
BirthDateRange = birthDateRange;
ApplicableDateRange = applicableDateRange;
}
}
public class DateRange
{
public DateRange(DateTime startDate, DateTime endDate)
{
StartDate = startDate;
EndDate = endDate;
}
DateTime _startDate;
DateTime _endDate;
public virtual DateTime StartDate
{
get { return _startDate; }
set { _startDate = value.ToUniversalTime(); }
}
public virtual DateTime EndDate
{
get { return _endDate; }
set { _endDate = value.ToUniversalTime(); }
}
}
This class defines a range of time where this agegroup is applicable. When the applicable date range is passed, we would need to shift everything in time. But is there a better way to do this?

Answer 1

If you're thinking of storing the age range within a person object of some description, I wouldn't, since (1) it's an easily calculable value from the birth date; and (2) it's not really a property of the object (it could be considered so but its transient nature will make things more complex than need be).
Instead, store only the birth date then provide some code which can give an age range based on that birth date and the current date.
You can still have age ranges but the people themselves do not exist "inside" them. Instead, you would be able to pass a person object to a function and have it give you back the relevant range.
And, if possible, the age ranges should be based on ages rather than birth dates, since the former is unchanging - you don't have to "move" objects between ranges since that's automatic when their range is calculated from their birth date and the current date.
If that's not possible (and it appears from your supplied chart that it may be difficult):
then you can use birth dates as you currently are but with a slight modification to allow for things to change year to year.
Have a season object which has the following fields:
Start date.
A collection of range objects.
This will allow you to have multiple season objects if, for example, the age ranges change in following years. As long as they don't change, you'll only have a single season object with a start date of whenever your 2014/15 season starts.
The range objects themselves are then a collection of objects of the form:
Start birth date End birth date Range name
---------------- -------------- ----------
1993-01-01 1993-07-31 U22
1993-08-01 1994-07-31 U21
1994-08-01 1995-07-31 U20
:
2009-08-01 2010-07-31 U5
2010-08-01 2010-12-31 U4
Then, in order to find out which age group someone belongs to, you:
Find the current season object, based on the date of the season (usually today, though it's conceivable you may want to look at earlier seasons as well).
Go through all the range objects for that season until you find one where the persons birth date falls between the start and end dates for the range. If you don't find an eligible range, then they're not allowed to play.
Then extract the range name.