Hi Jeff,
I've explained to Ed about this regarding custom paging.
Currently when we have custom paging and click in a datagrid column
header, the complete fill must be at the client side to be sorted.
By adding sortFields & sortDirections to the custom method and passing
them automatically to the customFill method, we are able to extract ANY
page of the collection in any order without having to collect all the
data items at the client.
few key points:
1) better user experience since it's lot faster to retrieve 1 page of
500 items instead of collecting 100.000+ items in the client just to
sort them.
2) it happens under the hood like it does for lazy loading support,
which requires 0 lines of code
3) less data crossing the wire and less load on the server
João Fernandes
Jeff Vroom wrote:
Hi João,
So I think that you can do this today where you just pass the sort
fields as additional fill parameters. Is there a reason you want the
sort fields broken out explicitly in the api?
Jeff
------------------------------------------------------------------------
*From:* flexcoders@yahoogroups.com [mailto:[EMAIL PROTECTED]
*On Behalf Of *João Fernandes
*Sent:* Thursday, August 30, 2007 4:05 AM
*To:* flexcoders@yahoogroups.com
*Subject:* Re: [flexcoders] FDS and Paging
Jeff,
I would like to see the custom paging method to be enhanced so it
would also pass the sort fields and their order.
I say fields because we could sort by multiples columns the paged
collection.
Once the client sort by n fields, those would be passed to the custom
fill method with their corresponding order and it would allow to
retrieve any page with any order without having to retrieve all the
collection to the client.
João Fernandes
Jeff Vroom wrote:
By default, DS will just page from the client to the server, not from
the server to the database. I'd expect it to call fill once, but
then the client fetches the data in pages.
Starting in LC DS 2.5, we added a mechanism to page directly to the
database. Currently it is limited in that you must set
autoSyncEnabled=false for it to work before you call fill (though we
hope to fix that limitation in the next release).
To use this you implement the variant of the fill method which takes
the start and count methods:
Collection fill(List fillParameters, int startIndex, int
numberOfRows);
You also must override the "useFillPage" method and have it return
"true" for that set of fill parameters.
There are two options for determining the size of the collection that
the client sees. It will call your assembler's count method with the
same fill parameters. If that returns -1, it goes into a dynamic
sizing mode where it makes the size of the collection on the client
pageSize+1 items, then when that one missing item is fetched it ups
the size to pageSize+pageSize+1, etc. until it hits the end.
By default when you sort in the data grid (or apply any filters) it
will page in all items automatically since the default behavior is to
sort on the client. This can be inefficient so you might want to
add the sort criteria to the fill parameters. You can then override
the sort behavior in the data grid to call fill again rather than
paging all of the items.
Jeff
------------------------------------------------------------------------
*From:* flexcoders@yahoogroups.com
[mailto:[EMAIL PROTECTED] *On Behalf Of *Alban Soupper
*Sent:* Wednesday, August 29, 2007 7:27 AM
*To:* flexcoders@yahoogroups.com
*Subject:* [flexcoders] FDS and Paging
Hi All,
I need some help with FDS and the paging feature.
Here is the situation:
I have a DataGrid that display a list of managed objects -- using DFS
and the Assembler strategy.
The number of objects is very large and is time consuming to load.
I would want to use the paging feature to deal with this situation.
I enabled the paging option in the destination descriptor, but the
behavior does not change.
The client just calls my assembler fill method always in the same way.
Did I miss some point?
What happens with the paging feature and the sort feature of the
Datagrid?
Any help is welcomed.
Alban.
************************************************************************************
This email and any attachments transmitted with it are confidential
and intended solely for the use of the individual or entity to whom
they are addressed. If you are not the intended recipient, any
disclosure, copying, use, or distribution of the information included
in this message and any attachments is strictly prohibited.
If you have received this email in error please notify the system
manager at [EMAIL PROTECTED] or by reply e-mail and immediately and
permanently delete this message and any attachments. Thank you.
************************************************************************************
