How can I enable different analyzers for each field in a document I'm indexing with Lucene? Example:
RAMDirectory dir = new RAMDirectory();
IndexWriter iw = new IndexWriter(dir, new StandardAnalyzer(Lucene.Net.Util.Version.LUCENE_CURRENT), true, IndexWriter.MaxFieldLength.UNLIMITED);
Document doc = new Document();
Field field1 = new Field("field1", someText1, Field.Store.YES, Field.Index.ANALYZED, Field.TermVector.WITH_POSITIONS_OFFSETS);
Field field2 = new Field("field2", someText2, Field.Store.YES, Field.Index.ANALYZED, Field.TermVector.WITH_POSITIONS_OFFSETS);
doc.Add(field1);
doc.Add(field2);
iw.AddDocument(doc);
iw.Commit();
The analyzer is an argument to the IndexWriter, but I want to use StandardAnalyzer for field1 and SimpleAnalyzer for field2, how can I do that? The same applies when searching, of course. The correct analyzer must be applied for each field.
PerFieldAnalyzerWrapper is what you are looking for. The equivalent of this in Lucene.net is here.
Map<String, Analyzer> analyzerMap = new HashMap<String, Analyzer>();
analyzerMap.put(fieldone, new IKAnalyzer4PinYin(false, IKAnalyzer4PinYin.PINYIN));
analyzerMap.put(fieldtwo, new IKAnalyzer4PinYin(false, KAnalyzer4PinYin.PINYIN_SHOUZIMU));
PerFieldAnalyzerWrapper wrapper = new PerFieldAnalyzerWrapper(new IKAnalyzer4PinYin(false), analyzerMap);
IndexWriterConfig iwConfig = new IndexWriterConfig(Version.LUCENE_40 , wrapper);
Necromancing.
For C#:
Lucene.Net.Util.LuceneVersion version = Lucene.Net.Util.LuceneVersion.LUCENE_48;
Dictionary<string, Lucene.Net.Analysis.Analyzer> fieldAnalyzers =
new Dictionary<string, Lucene.Net.Analysis.Analyzer>(System.StringComparer.OrdinalIgnoreCase);
fieldAnalyzers["YourFieldName"] = new Lucene.Net.Analysis.Core.KeywordAnalyzer();
Lucene.Net.Analysis.Miscellaneous.PerFieldAnalyzerWrapper wrapper =
new Lucene.Net.Analysis.Miscellaneous.PerFieldAnalyzerWrapper(
new Lucene.Net.Analysis.Core.KeywordAnalyzer(), fieldAnalyzers);
Lucene.Net.Index.IndexWriterConfig writerConfig = new Lucene.Net.Index.IndexWriterConfig(version, wrapper);
Related
I'm having some problems with Lucene that are driving me nuts. I have the following field:
doc.Add(new Field("cataloguenumber", i.CatalogueNumber.ToLower(), Field.Store.YES, Field.Index.ANALYZED));
Which will contain a catalogue number that looks something like this:
DF-GH5
DF-FJ4
DF-DOG
AC-DP
AC-123
AC-DOCO
i.e. two characters followed by a hyphen followed by 2-5 alphanumeric characters.
I'm trying to run a boolean query to allow users to search over the data:
// specify the search fields, lucene search in multiple fields
string[] searchfields = new string[] { "cataloguenumber", "title", "author", "categories", "year", "length", "keyword", "description" };
// Making a boolean query for searching and get the searched hits
BooleanQuery mainQuery = new BooleanQuery();
QueryParser parser;
//Add filter for main keyword
parser = new MultiFieldQueryParser(Lucene.Net.Util.Version.LUCENE_30, searchfields, new StandardAnalyzer(Lucene.Net.Util.Version.LUCENE_30));
parser.AllowLeadingWildcard = true;
mainQuery.Add(parser.Parse(GetMainSearchQueryString(SearchPhrase)), Occur.MUST);
The system is working fine for all fields EXCEPT cataloguenumber which for whatever reason is not working at all.
Ideally we would like to be able to search by full or partial cataloguenumber so for example "DF-" should return all items prefixed DF
Does anyone know how I can make this work?
Thanks very much in advance
Olly
A common source of problems is to use different analyzers on index-time and query-time. You should be able to get good results by using a StandardAnalyzer - it treats the text DF-GH5 as a single token so you will be able to search using fx df-gh5 or df-* but make sure to use it for the IndexWriter and the QueryParser.
Here is a simple example which builds an in-memory index with a single document, and tries to query the index by cataloguenumber.
public static void Test()
{
// Use an in-memory index.
RAMDirectory indexDirectory = new RAMDirectory();
// Make sure to use the same analyzer for indexing
Analyzer analyzer = new StandardAnalyzer(Lucene.Net.Util.Version.LUCENE_30);
// Add single document to the index.
using (IndexWriter writer = new IndexWriter(indexDirectory, analyzer, IndexWriter.MaxFieldLength.UNLIMITED))
{
Document document = new Document();
document.Add(new Field("content", "This is just some text", Field.Store.YES, Field.Index.ANALYZED));
document.Add(new Field("cataloguenumber", "DF-GH5", Field.Store.YES, Field.Index.ANALYZED));
writer.AddDocument(document);
}
var parser = new MultiFieldQueryParser(
Lucene.Net.Util.Version.LUCENE_30,
new[] { "cataloguenumber", "content" },
analyzer);
var searcher = new IndexSearcher(indexDirectory);
DoSearch("df-gh5", parser, searcher);
DoSearch("df-*", parser, searcher);
}
private static void DoSearch(string queryString, MultiFieldQueryParser parser, IndexSearcher searcher)
{
var query = parser.Parse(queryString);
TopDocs docs = searcher.Search(query, 10);
foreach (ScoreDoc scoreDoc in docs.ScoreDocs)
{
Document searchHit = searcher.Doc(scoreDoc.Doc);
string cataloguenumber = searchHit.GetValues("cataloguenumber").FirstOrDefault();
string content = searchHit.GetValues("content").FirstOrDefault();
Console.WriteLine($"Found object: {cataloguenumber} {content}");
}
}
I'm using Apache Lucene 5.5.3. I'm using org.apache.lucene.analysis.standard.StandardAnalyzer in my code and using below code snippet to create index.
Document doc = new Document();
doc.add(new TextField("userName", getUserName(), Field.Store.YES));
Now if I search for a string 'ALL-' , then I'm not getting any search results but if I search for a string 'ALL-Categories', then I'm getting some search results.
The same thing is happening for a string with special characters '+' , '.', '!' etc.
Below is my search code:-
Directory directory = new RAMDirectory();
IndexReader reader = DirectoryReader.open(directory);
IndexSearcher searcher = new IndexSearcher(reader);
Document document = new Document();
document.add(new TextField("body", ALL-THE GLITTERS IS NOT GOLD, Field.Store.YES));
IndexWriter writer = new IndexWriter(directory, new IndexWriterConfig(buildAnalyzer()));
writer.addDocument(document);
writer.commit();
Builder builder = new BooleanQuery.Builder();
Query query1 = new QueryParser(IndexAttribute.USER_NAME, buildAnalyzer()).parse(searchQUery+"*");
Query query2 = new QueryParser(IndexAttribute.IS_VETERAN, buildAnalyzer()).parse(""+isVeteran);
builder.add(query1, BooleanClause.Occur.MUST);
builder.add(query2, BooleanClause.Occur.MUST);
Query q = builder.build();
TopDocs docs = searcher.search(q, 10);
ScoreDoc[] hits = docs.scoreDocs;
private static Analyzer buildAnalyzer() throws IOException {
return CustomAnalyzer.builder().withTokenizer("whitespace").addTokenFilter("lowercase")
.addTokenFilter("standard").build();
}
So, Please suggest me on this.
Please refer section Escaping Special Characters to know special characters in Lucene 5.5.3.
As suggested in above article, you need to place a \ or alternatively you can use method public static String escape(String s) of QueryParser class to achieve the same.
I got the solution with WildcardQuery, StringField and MultiFieldQueryParser combination. In addition to these classes, we have to do is escape the space in the query string
I'm trying to index and then search integer field with lucene. But it doesn't find anything (Text fields search well).
Document doc = new Document();
//UserType = 1
doc.add(new IntField("userType", user.getType().getId(), Field.Store.YES));
FSDirectory dir = FSDirectory.open(FileSystems.getDefault().getPath(indexDir));
IndexWriterConfig config = new IndexWriterConfig(new StandardAnalyzer());
writer = new IndexWriter(dir, config);
writer.addDocument(doc);
For search I tried to use next queries:
1) new QueryParser(defautField, new StandartAnalyzer()).parse("userType:1");
2) new QueryParser(defautField, new StandartAnalyzer()).parse("userType:[1 TO 1]");
3) new QueryParser(defautField, new StandartAnalyzer()).parse("userType:\"1\"");
But it doesn't work.
QueryParser doesn't handle numerics. You can search using NumericRangeQuery:
Query query = NumericRangeQuery.newIntRange("userType", 1, 1, true, true);
I'm updating a document in Lucene, but when I search for the full value in one of the fields no results come back. If I search for just one word, then I get a result back.
This example comes from chapter 2 of the Lucene in Action 2nd Edition book and I'm using the Lucene 3 Java Library.
Here's the main logic
"Document fields show new value when updated, and not old value" in {
getHitCount("city", "Amsterdam") must equal(1)
val update = new Document
update add new Field("id", "1", Field.Store.YES, Field.Index.NOT_ANALYZED)
update add new Field("country", "Netherlands", Field.Store.YES, Field.Index.NO)
update add new Field("contents", "Den Haag has a lot of museums", Field.Store.NO, Field.Index.ANALYZED)
update add new Field("city", "Den Haag", Field.Store.YES, Field.Index.ANALYZED)
wr updateDocument(new Term("id", "1"), update)
wr close
getHitCount("city", "Amsterdam") must equal(0)
getHitCount("city", "Den Haag") must equal(1)
}
It's the last line in the above that fails - the hit count is 0. If I change the query to either "Den" or "Haag" then I get 1 hit.
Here is all the setup and dependencies. Note how the writer uses a white space query analyzer as the book suggests. Is this the problem?
override def beforeEach{
dir = new RAMDirectory
val wri = writer
for (i <- 0 to ids.length - 1) {
val doc = new Document
doc add new Field("id", ids(i), Field.Store.YES, Field.Index.NOT_ANALYZED)
doc add new Field("country", unindexed(i), Field.Store.YES, Field.Index.NO)
doc add new Field("contents", unstored(i), Field.Store.NO, Field.Index.ANALYZED)
doc add new Field("city", text(i), Field.Store.YES, Field.Index.ANALYZED)
wri addDocument doc
}
wri close
wr = writer
}
var dir: RAMDirectory = _
def writer = new IndexWriter(dir, new WhitespaceAnalyzer, IndexWriter.MaxFieldLength.UNLIMITED)
var wr: IndexWriter = _
def getHitCount(field: String, q: String): Int = {
val searcher = new IndexSearcher(dir)
val query = new TermQuery(new Term(field, q))
val hitCount = searcher.search(query, 1).totalHits
searcher.close()
hitCount
}
You may want to look at PhraseQuery instead of TermQuery.
I'm under the impression from a variety of tutorials out there on Lucene that if I do something like:
IndexWriter writer = new IndexWriter(indexPath, new StandardAnalyzer(Version.LUCENE_CURRENT), true, IndexWriter.MaxFieldLength.LIMITED);
Document doc = new Document();
Field title = new Field("title", titlefield, Field.Store.YES, Field.Index.ANALYZED);
doc.add(title);
writer.addDocument(doc);
writer.optimize();
writer.close();
IndexReader ireader = IndexReader.open(indexPath);
IndexSearcher indexsearcher = new IndexSearcher(ireader);
Term term1 = new Term("title", "one");
Term term2 = new Term("title", "two");
PhraseQuery query = new PhraseQuery();
query.add(term1);
query.add(term2);
query.setSlop(2);
that Lucene should return all queries for the title field containing "one" and "two" within 2 words of each other. But I don't get any results because I'm not using the StandardAnalyzer to search. How can do a proximity search in Lucene then? Does the following queryParser allow for proximity searches (using the tilde?)
QueryParser queryParser = new QueryParser("title",new StandardAnalyzer());
Query query = queryParser.parse("test");
yes, when you parse a query using QueryParser you will be able to do proximity searching.
In general it is always recommended to use the same analyser for indexing and searching.
BR,
Chris