Relationship properties

[jbailey]

My brain is drawing a blank on this:

Let's say I have a class Group and a class Person, where there's an n:m relationship between these. It's simple to say that Group could have an attribute "members" which is a collection of Persons, or Person could have an attribute "groups" which is a collection of Groups.

The problem then is that there's no relationship properties there. I can't easily describe for how long the person has been a member of the group, when that membership expires, etc. It seems to me that these type of properties ought to be describable in an elegant way. Perhaps as a characteristic of the array? I want to do this ideally in a way that for items that have no meaningful characteristics I can just use a standard Array class of some sort, but that when properties come up, I want to be able to add them silently so that existing code can continue to just work.

Comments

[malpingu.livejournal.com]

I agree with using a Membership association class, as suggested above. However, I would avoid dependence upon any particular implementation structure, such as Array, and instead use getter/setter methods for better abstraction.