public IMultiLevelCursorIterator <TInput, TOutput> Create <TDTO, TInput, TOutput>(
ITwitterPageIterator <ITwitterResult <TDTO> > pageIterator,
Func <TDTO, TInput[]> transform,
Func <TInput[], Task <TOutput[]> > getChildItems,
int maxPageSize)
{
var iterator = new MultiLevelCursorIterator <TInput, TOutput>(
async() =>
{
var userIdsPage = await pageIterator.NextPage().ConfigureAwait(false);
return(new CursorPageResult <TInput, string>
{
Items = transform(userIdsPage.Content.DataTransferObject),
NextCursor = userIdsPage.NextCursor,
IsLastPage = userIdsPage.IsLastPage
});
}, async inputs =>
{
var userIdsToAnalyze = inputs.Take(maxPageSize).ToArray();
var friends = await getChildItems(userIdsToAnalyze).ConfigureAwait(false);
return(new MultiLevelPageProcessingResult <TInput, TOutput>
{
Items = friends,
AssociatedParentItems = userIdsToAnalyze,
});
});
return(iterator);
}
public async Task Act()
{
if (_iterator.NextCursor != null)
{
throw new InvalidOperationException("Cannot run with pre executed iterator");
}
while (!_iterator.Completed)
{
var page = await _iterator.NextPage();
_resultPages.Add(page);
}
}