[Dev] Item Collection Spec 0.1

[Phillip J. Eby]

At 05:44 PM 6/2/2005 -0700, John Anderson wrote:
>Currently notifications fire only for UI that's visible. However, the way 
>the repository works today makes initialization of non-persistent data 
>hopelessly complicated -- we spent many man months trying to make it work 
>before giving up and going with the persistent model, and since then life 
>has been much better. Some of these problems could be address by changing 
>the repository, however, I haven't been able to make that happen.

And that's a fine answer, if that's the reasoning behind the proposal.  It 
just wasn't in there, and "if it's persistent it's simpler" didn't convey 
that information either.

However, I'm confused as to why you say initialization of something like 
that would be complicated.  The visual components receive messages that 
tell them they're being shown or hidden, so that seems to me like it would 
be an obvious time to activate or deactivate a subscription for 
notifications.  This doesn't have anything to do with "initialization of 
non-persistent data" in the general sense; only visual components in 
particular.

Such an approach avoids the need to commit the subscribes and unsubscribes 
to the persistent store as the component's visual state changes, for 
example.  It also avoids the issue of persistent callbacks occurring in 
multiple repository views; instead the callback could be view-specific.