UserTagDesign

[Karl Wettin <ka...@gmail.com>]

I've been looking at <http://wiki.apache.org/solr/UserTagDesign> on  
and off for a while and think all the use cases could be explained  
with simple UML class diagram semantics:

> [Taggable](tag:Tag)-- {0..*} ----|--- {0..*} --(tag:Tag)[Tagger]
>
>                                  |
>                              [Tagging]

Rendered: <http://ginandtonique.org/~kalle/tagging.pdf>

This is of course a design that might not fit everybody, it could be  
represented using an n-ary association or what not. But I find the  
text on the wiki much easier to follow with this in my head.

How (or even if) one would represent this in a index is a completely  
different story.

Translated to Java the diagram would look something like this:

> /** the user */
> class Tagger {
>   Map<Tag, Set<Tagging>> taggingsByTag;
> }
>
> /** the content */
> class Taggable {
>   Map<Tag, Set <Tagging>> taggingsByTag;
> }
>
> /** content tagging */
> class Tagging {
>   Tagger tagger;
>   Taggable tagged;
>   Date created;
> }
>
> class Tag {
>   String text;
> }

Thought it was better to let you people decide whether or not this  
fits in the wiki.


-- 
karl