Create a Simple highlight formatter for Lucene.net 3.0.3

Question

I'm using Lucene.Net 3.0.3 and I have working code but I can't figure out how to add a simple formatter.

    Public Function Lucene_Index_Search_Complete(term As String) As String
    Dim sb As New StringBuilder()
    Dim sw As New StringWriter(sb)
    Dim writer As JsonWriter = New JsonTextWriter(sw)
    Try
        Dim d As Lucene.Net.Store.Directory = FSDirectory.Open(New DirectoryInfo(Server.MapPath("~") + "\\IndexedFiles_V33\\"))
        Dim indexReader As IndexReader = indexReader.Open(d, True)
        Dim indexSearch As Searcher = New IndexSearcher(indexReader)
        Dim a As Analyzer = New StandardAnalyzer(Lucene.Net.Util.Version.LUCENE_30)

        'IFormatter formatter = new SimpleHTMLFormatter("<b>", "</b>");


        Dim HighlightFormatter As SimpleHTMLFormatter = New SimpleHTMLFormatter("<span style='background:yellow;'>", "</span>")

        Dim FieldNames As String() = indexReader.GetFieldNames(indexReader.FieldOption.INDEXED_NO_TERMVECTOR).toArray
        Dim parser As MultiFieldQueryParser = New MultiFieldQueryParser(Lucene.Net.Util.Version.LUCENE_30, FieldNames, a)

        Dim q As BooleanQuery = New BooleanQuery()

        term = term.Trim

        Dim phases As String() = Nothing
        If term.contains(",") Then
            phases = Split(term, ",")
            For Each phase As String In phases
                q.Add(parser.Parse(phase), Occur.SHOULD)
            Next
        Else
            phases = Split(term, " ")
            For Each phase As String In phases
                q.Add(parser.Parse(phase), Occur.MUST)
            Next
        End If



        Dim collector As TopScoreDocCollector = TopScoreDocCollector.create(1000, True)
        indexSearch.Search(q, collector)

        Dim hits As ScoreDoc() = collector.topDocs().scoreDocs


        Dim GrantID As String = ""
        Dim Title As String = ""
        Dim Posted_Date As String = ""
        Dim link As String = ""
        Dim jsonData As JObject = Nothing
        Dim purpose As String = ""
        Dim Short_Description As String = ""

        ' Loop through the matching hits, retrieving the document
        writer.WriteStartArray()
        For i As Integer = 0 To hits.Length - 1
            Try
                If i >= 50 Then
                    Exit For
                End If

                Dim docId As Integer = hits(i).doc
                Dim doc As Document = indexSearch.doc(docId)
                Dim Score As String = hits(i).Score.tostring
                GrantID = doc.get("GrantID")
                link = doc.get("link")
                jsonData = JObject.Parse(doc.get("JSON_Data"))
                Title = jsonData("Funding Opportunity Title").ToString
                Posted_Date = jsonData("Posted Date").ToString
                purpose = jsonData("Funding Opportunity Purpose").ToString

                writer.WriteStartObject()
                writer.WritePropertyName("id")
                writer.WriteValue((1 + i).ToString)
                writer.WritePropertyName("Grant_ID")
                writer.WriteValue(GrantID)
                writer.WritePropertyName("text")
                writer.WriteValue("<br/>" + Title + "<br/>" + purpose + "<br/><b>Score:</b> " + Score + "<br/>")
                writer.WritePropertyName("Score")
                writer.WriteValue(Score)
                writer.WriteEndObject()

            Catch ex As Exception
                WriteErrorLog(ex.Message, link)

            End Try
        Next

        writer.Close()


        Return sb.ToString




    Catch ex As Exception
        Return ex.Message

    End Try

End Function

All I want to do is to wrap the term with a yellow background. Any help is appreciated because I have searched for the answer and I think that I must be missing something. I need to highlight the search terms that are in the JSON fields of Funding Opportunity Purpose and Funding Opportunity Title

Answer 1

got it done

 Public Function GeneratePreviewSimpleText(q As Query, text As String, fieldName As String) As String
    Try
        Dim scorer As QueryScorer = New QueryScorer(q)
        Dim formatter As IFormatter = New SimpleHTMLFormatter("<span style='background:yellow;'>", "</span>")
        Dim fragmenter As SimpleFragmenter = New SimpleFragmenter(50)
        Dim highlighter As Highlighter = New Highlighter(formatter, scorer)
        highlighter.TextFragmenter = fragmenter
        Dim stream As TokenStream = New StandardAnalyzer(Lucene.Net.Util.Version.LUCENE_30).TokenStream(fieldName, New StringReader(text))


        Return highlighter.GetBestFragments(stream, text, 4, "<br/>")

    Catch ex As Exception

    End Try
End Function