/// <summary>
/// method to return the whole Lucene search index
/// </summary>
/// <returns></returns>
public IEnumerable <LearningCourseDTO> GetAllIndexRecords()
{
// validate search index
if (!System.IO.Directory.EnumerateFiles(_luceneDir).Any())
{
return(new List <LearningCourseDTO>());
}
// set up lucene searcher
var searcher = new IndexSearcher(_directory, false);
var reader = IndexReader.Open(_directory, false);
var docs = new List <Document>();
var term = reader.TermDocs();
while (term.Next())
{
docs.Add(searcher.Doc(term.Doc));
}
reader.Dispose();
searcher.Dispose();
var mapper = new LearningCourseMapper();
return(mapper.MapLuceneToDataList(docs));
}
/// <summary>
///
/// </summary>
/// <param name="searchQuery"></param>
/// <param name="searchField"></param>
/// <returns></returns>
public IEnumerable <LearningCourseDTO> GetSearchResults(string searchQuery, string searchField = "")
{
// validation
if (string.IsNullOrEmpty(searchQuery.Replace("*", "").Replace("?", "")))
{
return(new List <LearningCourseDTO>());
}
// set up lucene searcher
using (var searcher = new IndexSearcher(_directory, false))
{
var hits_limit = 1000;
var analyzer = new StandardAnalyzer(Lucene.Net.Util.Version.LUCENE_30);
//if one need to add new field to search:
//var parser = new MultiFieldQueryParser
//(Version.LUCENE_30, new[] { "Id", "Name", "Description", "NEW_FIELD" }, analyzer);
// search by single field
if (!string.IsNullOrEmpty(searchField))
{
var parser = new QueryParser(Lucene.Net.Util.Version.LUCENE_30, searchField, analyzer);
var query = parseQuery(searchQuery, parser);
var hits = searcher.Search(query, hits_limit).ScoreDocs;
var mapper = new LearningCourseMapper();
var results = mapper.MapLuceneToDataList(hits, searcher);
analyzer.Close();
searcher.Dispose();
return(results);
}
// search by multiple fields (ordered by RELEVANCE)
else
{
var parser = new MultiFieldQueryParser
(Lucene.Net.Util.Version.LUCENE_30, new[] { "Name", "Description" }, analyzer);
var query = parseQuery(searchQuery, parser);
var hits = searcher.Search
(query, null, hits_limit, Sort.RELEVANCE).ScoreDocs;
var mapper = new LearningCourseMapper();
var results = mapper.MapLuceneToDataList(hits, searcher);
analyzer.Close();
searcher.Dispose();
return(results);
}
}
}
