public StoryCollection Find(int hostId, int storyId)
{
int?docId = ConvertStoryIdtoDocId(hostId, storyId);
if (docId.HasValue)
{
IndexSearcher indexSearch = SearchQuery.GetSearcher(hostId);
IndexReader indexReader = indexSearch.GetIndexReader();
MoreLikeThis mlt = new MoreLikeThis(indexReader);
mlt.SetAnalyzer(new DnkAnalyzer());
//mlt.SetFieldNames(new string[] { "title", "description" });
//these values control the query used to find related/similar stories
//
//-we are only using the title and tags fields,
//-the term must appear 1 or more times,
//-the query will only have 3 terms
//-a word less than 3 char in len with be ignored
//-the term must appear at in at least 4 doc
mlt.SetFieldNames(new string[] { "title", "tags" });
mlt.SetMinTermFreq(1);
mlt.SetMaxQueryTerms(5);
mlt.SetMinWordLen(3);
mlt.SetMinDocFreq(4);
mlt.SetStopWords(StopWords());
mlt.SetBoost(true);
Query mltQuery = mlt.Like(docId.Value);
Hits hits = indexSearch.Search(mltQuery);
List <int> results = new List <int>();
for (int i = 0; i < hits.Length(); i++)
{
Document d = hits.Doc(i);
int hitStoryId = int.Parse(d.GetField("id").StringValue());
if (hitStoryId != storyId)
{
results.Add(hitStoryId);
if (results.Count == NUMBER_OF_RELATED_STORIES_TO_RETURN)
{
break;
}
}
}
return(SearchQuery.LoadStorySearchResults(results));
}
else
{
return(null);
}
}
/// <summary>
/// Converts storyId as used in the database to the docId as used in lucene
/// </summary>
/// <param name="hostId"></param>
/// <param name="storyId"></param>
/// <returns>returns the docId for the story from lucene. If the story is not
/// found a null value will be returned</returns>
protected int?ConvertStoryIdtoDocId(int hostId, int storyId)
{
QueryParser queryParser = new QueryParser("id", new DnkAnalyzer());
Query q = queryParser.Parse(storyId.ToString());
IndexSearcher searcher = SearchQuery.GetSearcher(hostId);
Hits hits = searcher.Search(q);
if (hits.Length() > 0)
{
return(hits.Id(0));
}
return(null);
}