GWT 2.2 AsyncDataProvider / CellTable gotcha

I’ve been trying out CellTable in GWT 2.2 and found a potential gotcha. I created an AsyncDataProvider and attached the CellTable to it, but found that the table does not refresh properly unless you update BOTH row count and row data. If you call only updateRowData(), the CellTable will show the loading bar when there are zero rows, and will not remove rows when you delete them in the provider. The solution is simple: whenever you want to update a CellTable bound to an AsyncDataProvider, be sure to call both updateRowData() and updateRowCount(). Example code here:

	public static class ListDataProvider extends
			AsyncDataProvider<ItemListProxy>
	{
		private Logger logger = Logger
				.getLogger(ListsActivity.ListDataProvider.class.getName());
		private ListwidgetRequestFactory rf;

		public ListDataProvider(ListwidgetRequestFactory requestFactory)
		{
			this.rf = requestFactory;
		}

		@Override
		protected void onRangeChanged(HasData<ItemListProxy> display)
		{
			getData();
		}
		
		private void getData()
		{
			logger.warning("getting data");
			// To retrieve relations and value types, use .with()
			Request<List<ItemListProxy>> findAllReq = rf.itemListRequest()
					.listAll().with("owner");
			// Receiver specifies return type
			findAllReq.fire(new Receiver<List<ItemListProxy>>()
			{
				@Override
				public void onSuccess(List<ItemListProxy> response)
				{
					updateRowCount(response.size(), true);
					updateRowData(0, response);
				}
			});
		}
	}

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