> Why not have
>
> public interface DataProvider extends Serializable {
>
> Iterator getElements(int first, int minCount);
> int getCount();
> }
>
I was definetely thinking of doing that, didn't get to it yet. A list was
simply the most convinient because that's what EntityManager returns and I
didn't have to rewrite too much existing listview code. As I said this was
just a proof-of-concept to test the interface idea.
Maybe one of the wicket devels can create a project for us in one of the
subprojects and we can collaborate if you are interested.
> If you have a List you have an Iterator and an Iterator will
> work for any Collection (and more). I think minCount should
> tell just the minimum number of elements the iterator should
> contain. This is just to get it easy and cheap from a List.
> (Maybe alternatively it could also be just a hint so that the
> iterator could actually be smaller).
If I understand you correctly you would like to provide the min amount of
entries and have the iterator access more if they are needed? If so, this is
one of the things I was trying to eliminate. Currently dataview asks your
dataprovider for the exact segment of data it needs and so it eliminates the
whole need for retrieving data window by window.
If you want to connect a list all you have to do is list.sublist(first,
first+count).iterator()
> Maybe keep the Object to IModel translation in the DataView
> (ListView) - I have to extend it anyway. In case it is a
> horizontal concern, you could easaly write a delegating
> Iterator: (and plug it in whereever you need it)
>
> public class ModelIterator implements Iterator{
> private Iterator _delegate;
> public boolean hasNext(){
> return _delegate.hasNext();
> }
> public Object next(){
> return makeIModel(_delegate.next());
> }
> ......
> }
In order to achieve this the default impl of getlistitemmodel() in the
dataview would have to pass the object through unchanged. Is that what you
are thinking?
Also, where would be a good point to wrap the iterator? I will have to play
with this tomorrow to see. Let me know if you have any ideas.
Igor
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