/// <summary>
/// 从局部缓存中获取论文的引用次数。
/// </summary>
private int?CitationCount(PaperNode node)
{
Debug.Assert(node != null);
int count;
if (_CitationCountDict.TryGetValue(node.Id, out count))
{
return(count);
}
return(null);
}
private async Task FetchCitationsToPaperAsync(PaperNode paper, string constraint, ConcurrentPagingMode pagingMode)
{
Debug.Assert(paper != null);
if (constraint == null)
{
if (!await GetStatus(paper.Id).MarkAsFetchingOrUntilFetched(NodeStatus.PaperCitationsFetching))
{
return;
}
}
// 一般来说， Paper2 肯定就是题目中的终结点，
// 因此我们是知道其具体信息的。
var maxPapers = CitationCount(paper);
var strategy = maxPapers == null
? ConcurrentPagingMode.Optimistic
: pagingMode;
if (maxPapers == null)
{
maxPapers = Assumptions.PaperMaxCitations;
}
var expr = SEB.ReferenceIdContains(paper.Id);
if (constraint != null)
{
expr = SEB.And(expr, constraint);
}
await SearchClient.EvaluateAsync(expr, maxPapers.Value, strategy, async page =>
{
await Task.WhenAll(page.Entities.Select(entity =>
{
RegisterNode(entity);
return(ExplorePaperAsync(entity));
}));
});
if (constraint == null)
{
GetStatus(paper.Id).MarkAsFetched(NodeStatus.PaperCitationsFetching);
}
}
