The purpose of size() is to give the DataView an idea of how many
pages there will be, so this really won't work. You should fetch size
in a separate query as the number of orders total over all pages, and
cache that.
best,
jim
On 5/29/07, V. Jenks <[EMAIL PROTECTED]> wrote:
>
> I'm trying to use a provider class for a DataView so I can do paging/sorting,
> etc. It looks like this:
>
> ************************************************
> public class OrderProvider implements IDataProvider
> {
> private transient List<Order> orders;
>
> public OrderProvider()
> {
> }
>
> public Iterator iterator(int first, int count)
> {
> this.orders =
> WicketHelper.<List<Order>>getDetachedModelObject(
> OrderProxy.getAll(first, first + count));
>
> return this.orders.iterator();
> }
>
> public IModel model(Object model)
> {
> return WicketHelper.getDetachedModel(model);
> }
>
> public int size()
> {
> return this.orders.size();
> }
> }
> ************************************************
>
> I thought this would work but it looks like size() is called first, since I
> get a NPE:
>
> ************************************************
> Caused by: java.lang.NullPointerException
> at com.myapp.provider.OrderProvider.size(OrderProvider.java:36)
> ************************************************
>
> It works if size() makes a call to the database to get a count of
> records...but I'm trying to use a global field to prevent that data call.
>
> Any suggestions?
> --
> View this message in context:
> http://www.nabble.com/Chicken-and-egg-w--Data-Provider-tf3834369.html#a10855464
> Sent from the Wicket - User mailing list archive at Nabble.com.
>
>
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