[Dev] Problem with collection notifications

[John Anderson]

Philippe Bossut wrote:

>
>
> John Anderson wrote:
>
>>
>> Blocks should always be model, widgets should always be view.
>
>
> I'm assuming this to make sense of the next paragraph.
>
>> If the selection isn't part of the block or the collection it won't 
>> be persisted, which won't work. In relality the selection is stored 
>> in both the widget and a block or collection. 
>
>
> As far as I remember, Views are supposed to be "data ignorant". For 
> sure, a model data cannot be stored in Views and Model at the same 
> time. So, either:
> - Block/Widgets/xx are not following the MVC model and we should not 
> continue to use this term in the discussion
> or
> - We need to fix Block/Widgets so that they are conforming to MVC
>
> I have no religion as to whether or not we should use MVC and I know 
> of quite a few good UI that didn't use them. I think however we should 
> not call something MVC if it's not.

I don't agree with this. I think the MVC description make sense in this 
context and helps improve the understanding and simplify the design -- 
even though a widget (which we don't control), happens to also have a 
local cache of the data (which isn't persisted).

>
>> We need to keep they in sync. If the widget changes its selection we 
>> need to reflect it in a persistant model. If something outside the 
>> platform changes the persistent model we need to have a way to 
>> sychronize the widgets's idea of the selection.
>>
> So, MVC discussion aside, it looks like widgets and blocks should be 
> able to decide individually when receiving a notification if they are 
> already synced or not and, if they are, hold off generating 
> notification themselves, therefore stopping the notification generation.

It's often difficult to write a piece of code that can tell we're 
already synced, so we sometimes have to update more than what really 
changed. Therefore, any time we can easily eliminate unnecessary 
notificaitons it's nice to take advange of them.

>
> Philippe