(responding to Eric D. Tarkington)
> I'm working with a person who thinks that a catalog is an aggregate of > catalog items, but a list is not an aggregate of list items. > > Catalog, CatalogItem, List, and ListItem are all classes. > > I think that aggregation is not just a "part of" relationship (which > doesn't seem arguable), it can also be a "has a" relationship in a more > general way. I think that I have design authority to say that a List > (with an unspecified set of access methods) is an aggregate of > ListItems. I assume you complain because your 'person' thinks a List is not at all an aggregate of ListItem, rather than not _ just_ all an aggregate of ListItem. List can mean different things to different people, and it is up to the Domain Expert to clarify to the modeller what behaviour is required to be modelled in this instance. It is up to the modeller to specify this behaviour in the model. Having said this, most people, when they talk about Lists are, IMHO, talking about sequenced aggregations of ListItem. Problems can arise where people are looking at different levels, and I'd guess your 'person' might be considering an implementation model rather than a more abstract form suitable for earlier in the process. HTH, Paul Oldfield any opinions expressed herein are not necessarily those of Mentors of Cally ************************************************************************ * Rose Forum is a public venue for ideas and discussions. * For technical support, visit http://www.rational.com/support * * Admin.Subscription Requests: [EMAIL PROTECTED] * Archive of messages: http://www.rational.com/support/usergroups/rose/rose_forum.jsp * Other Requests: [EMAIL PROTECTED] * * To unsubscribe from the list, please send email * * To: [EMAIL PROTECTED] * Subject:<BLANK> * Body: unsubscribe rose_forum * *************************************************************************
