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.
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