Lucene.Net.Search.DocIdSetIterator.Empty C# (CSharp) Method

        public static DocIdSetIterator Empty()
        {
            return new DocIdSetIteratorAnonymousInnerClassHelper();
        }

            public override Explanation Explain(AtomicReaderContext ir, int i)
            {
                Explanation      inner            = Weight.Explain(ir, i);
                Filter           f                = OuterInstance.Filter_Renamed;
                DocIdSet         docIdSet         = f.GetDocIdSet(ir, ir.AtomicReader.LiveDocs);
                DocIdSetIterator docIdSetIterator = docIdSet == null?DocIdSetIterator.Empty() : docIdSet.GetIterator();

                if (docIdSetIterator == null)
                {
                    docIdSetIterator = DocIdSetIterator.Empty();
                }
                if (docIdSetIterator.Advance(i) == i)
                {
                    return(inner);
                }
                else
                {
                    Explanation result = new Explanation(0.0f, "failure to match filter: " + f.ToString());
                    result.AddDetail(inner);
                    return(result);
                }
            }