[Standards] One more pubsub question: Name space for Nodes/Items under a Collection Node

Ralph Meijer jabber.org at ralphm.ik.nu
Thu Jan 25 08:27:44 UTC 2007


On Thu, 2007-01-25 at 00:53 -0500, Nick Parker wrote:
> In a tree of PubSub nodes, is there a single universal namespace across 
> the entire server, or is it okay for two nodes to share the same ID if 
> they are stored under different collection nodes?
> 
> Here's an example configuration of node IDs, do any of the combinations 
> lead to a collision?:
> 
> Root Collection P
>   Node A
>   Sub-Collection X
>     Node A
>     Node B
>   Sub-Collection Y
>     Node B
>     Node C
>     Node D
> Root Collection Q
>   Node C
>   Sub-Collection X
>     Node D

This shouldn't lead to any problems. Basically collections let you
create a directed acyclic graph. The nodes you show with the same name
are the same nodes. Taking 'A' as an example, when it generates
notifications, subscribers to nodes P, X and A will get those
notifications.

One thing to note is that we have only one 'root' node, which is the
node with the empty identifier. It contains all the 'real' nodes in the
service.


> This question would also apply to Items which are stored under different 
> Nodes but share the same IDs.

Item IDs are (only) unique to their node. Collections don't contain
items.

-- 
Groetjes,

ralphm




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