protected virtual IEnumerable<int> GetCandidates(QueryParser qparser, IList<IList<int>> posting_lists, IIntersection<int> ialg)
{
if (posting_lists.Count == 0) {
return new int[0];
} else if (posting_lists.Count == 1) {
return posting_lists [0];
} else {
return ialg.Intersection (posting_lists);
}
}
protected virtual IList<IList<int>> GetPostingLists(QueryParser qparser)
{
var posting_lists = new List<IList<int>> ();
for (int i = 0; i < qparser.Query.Count; ++i) {
int symbol;
if (qparser.Query[i] != null && this.RankVoc (qparser.Query [i], out symbol)) {
var rs = this.Seq.Unravel (symbol);
var L = new SortedListRSCache (rs, -i);
posting_lists.Add (L);
}
}
return posting_lists;
}
public virtual IList<int> SearchPhrase(string query, IIntersection<int> ialg, Action<QueryParser> modify_query = null)
{
var qparser = new QueryParser (this.InputTokenizer);
qparser.Parse (query);
if (null != modify_query) {
modify_query (qparser);
}
var posting = this.GetPostingLists (qparser);
var _r = this.GetCandidates (qparser, posting, ialg);
var _s = _r as IList<int>;
if (_s == null) {
return new List<int> (_r);
}
return _s;
}
