> > Message: 5 > Date: Thu, 2 Apr 2009 10:53:04 +0200 > From: Rong Chen <rong.acode at gmail.com> > Subject: Re: Question about the item property of Item_Tree > To: For openEHR technical discussions <openehr-technical at openehr.org> > Message-ID: > ? ? ? ?<ebd0d070904020153y4bac0b48yb794a8b7fa2885d8 at mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1 > > Hi Seref, > > Interesting thought! I think this comes down to a design choice, which > is whether we want to force single-rooted tree. By definition, tree > data structure has a single root. But when we model hierarchical > structure of clinical content, it's convenient to allow multiple nodes > at the top level of the tree without the need to create a root node > just to satisfy the notion of single-rooted tree. So it's a choice > between purity (according to computer science definition of a tree) > and convenience (which somewhat indirectly translated to usability of > the model and relevant tools). > > Cheers, > Rong >
Not sure if it helps in the design but in Java (Swing) the JTree control's model has a tree data structure (per comp sci definition) but to display a multiple top level nodes you can mark the root node as hidden.
