/// <summary>
/// This method indexes the content that is sent across to it. Each piece of content (or "document")
/// that is indexed has to have a unique identifier (so that the caller can take action based on the
/// document id). Therefore, this method accepts key-value pairs in the form of a dictionary. The key
/// is a ulong which uniquely identifies the string to be indexed. The string itself is the value
/// within the dictionary for that key. Be aware that stop words (like the, this, at, etc.) are _not_
/// indexed.
/// </summary>
/// <param name="txtIdPairToBeIndexed">A dictionary of key-value pairs that are sent by the caller
/// to uniquely identify each string that is to be indexed.</param>
/// <returns>The number of documents indexed.</returns>
public int Index(Dictionary<ulong, string> txtIdPairToBeIndexed, IndexContentType indexContentType)
{
IndexWriter indexWriter = new IndexWriter (_indexDir, new StandardAnalyzer (), true);
indexWriter.SetUseCompoundFile (false);
Dictionary<ulong, string>.KeyCollection keys = txtIdPairToBeIndexed.Keys;
foreach (ulong id in keys) {
string text = txtIdPairToBeIndexed[id];
Document document = new Document ();
Field bodyField = new Field (indexContentType.ToString (), text, Field.Store.YES, Field.Index.TOKENIZED);
document.Add (bodyField);
Field idField = new Field (DOC_ID_FIELD_NAME, (id).ToString (), Field.Store.YES, Field.Index.TOKENIZED);
document.Add (idField);
indexWriter.AddDocument (document);
}
int numIndexed = indexWriter.DocCount ();
indexWriter.Optimize ();
indexWriter.Close ();
return numIndexed;
}
/// <summary>
/// This method searches for the search term passed by the caller.
/// </summary>
/// <param name="searchTerm">The search term as a string that the caller wants to search for within the
/// index as referenced by this object.</param>
/// <param name="ids">An out parameter that is populated by this method for the caller with docments ids.</param>
/// <param name="results">An out parameter that is populated by this method for the caller with docments text.</param>
/// <param name="scores">An out parameter that is populated by this method for the caller with docments scores.</param>
public void Search(string searchTerm, IndexContentType indexContentType, out ulong[] ids, out string[] results, out float[] scores)
{
IndexSearcher indexSearcher = new IndexSearcher (_indexDir);
try {
QueryParser queryParser = new QueryParser (indexContentType.ToString (), new StandardAnalyzer ());
Query query = queryParser.Parse (searchTerm);
Hits hits = indexSearcher.Search (query);
int numHits = hits.Length ();
ids = new ulong[numHits];
results = new string[numHits];
scores = new float[numHits];
for (int i = 0; i < numHits; ++i) {
float score = hits.Score (i);
string text = hits.Doc (i).Get (indexContentType.ToString ());
string idAsText = hits.Doc (i).Get (LuceneIndexer.DOC_ID_FIELD_NAME);
ids[i] = UInt64.Parse (idAsText);
results[i] = text;
scores[i] = score;
}
} finally {
indexSearcher.Close ();
}
}
