1. CS276 Lucene Section

2. Agenda
Lucene overview
Specific examples
Luke

3. Lucene: overview Apache Java text indexing project Rich query syntax
Sorts returned results by variant of tf-idf

4. Lucene: indexing
IndexWriter writer = new IndexWriter(indexPath, new StandardAnalyzer(), true, IndexWriter.MaxFieldLength.LIMITED);
Document doc = new Document();
doc.add(new Field("test", "value", Field.Store.YES, Field.Index.ANALYZED));
writer.addDocument(doc);
writer.close();

5. Lucene: querying 1
Query query = new QueryParser("some field", new StandardAnalyzer()).parse("some value");
Hits hits = indexSearcher.search(query);
for (int ind = 0; ind < Math.min(hits.length(), 20); ind++) {
Document doc = hits.doc(ind);
System.out.println(printDocument(doc, hits.score(ind),"some field")); }

6. Lucene: querying 2
ery.html
Query query = new TermQuery(new Term("some field","value"));
Hits hits = indexSearcher.search(query);
for (int ind = 0; ind < Math.min(hits.length(), 20); ind++) {
Document doc = hits.doc(ind);
System.out.println(printDocument(doc, hits.score(ind),"some field")); }

7. Lucene: querying 3
Query query = new TermQuery(new Term("some field","value"));
TopDocs docs = indexSearcher.search(query, 20);
for (int ind = 0; ind < docs.totalHits; ind++) {
int docID = docs.scoreDocs[ind].doc;
Document doc = indexSearcher.doc(docID);
System.out.println(printDocument(doc, hits.score(ind),"some field")); }

8. Lucene: common problems
No errors when field doesn't exist
Update = delete + add
There is max field length
javac -cp lib/lucene-core jar:lib/lucene- spellchecker jar