Adding/Removing items dynamically

Otake

Hi,

I have a scenario where I need to add new items or remove existing ones from my NonVisualTable subscription. I could not see any API for this; am I supposed to re-subscribe (pushPage.addTable) again every time I need to modify the list of items that I need to subscribe.

If that is the way, how would client library behave; will it actually make the calculation and remove/add the necessary ones or remove everything and add everything again?

Dario Crivelli

The tables are always managed atomically and if you reissue addTable all the previous content is unsubscribed first.
You can simply define multiple tables, one for each item, so that you can remove and add table instances directly.
This may introduce some redundancy, but the Web Client library is able to manage the case in an optimized way.

Note that you would have to create multiple NonVisualTable object, but you could still reuse the same callbacks for all of them.

Otake

If I subscribe an item that has been already subscribed to a different table; when there is an update on this item, will the same callback method of these tables fire twice?

Otake

Also if I use like 100 tables (each one is for one single item), would that be a problem?
(I have multiple grids and windows using the same information and they can be closed/opened indivdually)

Dario Crivelli

Yes, multiple subscriptions for the same item are managed independently from one another.
If the same callback method is used and you still need to distinguish the two subscriptions, you could add custom attributes to the two NonVisualTable instances.

If you have a lot of items, the screen update activity is more likely to become the main bottleneck.
In this perspective, using one multi-item table or multiple mono-item tables does not change the performances.
Performing 100 mono-item table subscriptions in a burst does not cause 100 HTTP requests to be issued to the Server, as the requests are batched; so, the performances are not expected to degrade.
Resubscribing upon page changes is then very light, as shown by our Grid Demo.

Otake

Many thanks for detailed clarification.