internal void Build(IndexReader indexReader)
{
indexReader.ExtractTermsForField(this.Field)
.Select(x => new { Value = x.Item1, MatchingDocuments = this.GetBitSetFromFilter(x.Item2, indexReader), Filter = x.Item2 })
.ToList()
.ForEach(x => this.AddValue(x.Value, x.MatchingDocuments, x.Filter));
}