I attach a junit test which shows strange behaviour of the inOrder parameter on the SpanNearQuery constructor, using Lucene 2.9.4.
My understanding of this parameter is that true forces the order and
false doesn't care about the order.
Using true always works. However using false works fine when the terms
in the query are distinct, but if they are equivalent, e.g. searching
for "john john", I do not get the expected results. The workaround seems
to be to always use true for queries with repeated terms.
Any help?
Thanks
Greg
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.TopDocsCollector;
import org.apache.lucene.search.TopScoreDocCollector;
import org.apache.lucene.search.spans.SpanNearQuery;
import org.apache.lucene.search.spans.SpanQuery;
import org.apache.lucene.search.spans.SpanTermQuery;
import org.apache.lucene.store.RAMDirectory;
import org.apache.lucene.util.Version;
import org.junit.Assert;
import org.junit.Test;
public class TestSpanNearQueryInOrder {
@Test
public void testSpanNearQueryInOrder() {
RAMDirectory directory = new RAMDirectory();
IndexWriter writer = new IndexWriter(directory, new
StandardAnalyzer(Version.LUCENE_29), true,
IndexWriter.MaxFieldLength.UNLIMITED);
TopDocsCollector collector = TopScoreDocCollector.create(3, false);
Document doc = new Document();
// DOC1
doc.add(new Field("text","dddd aaaa bbbb cccc", Field.Store.YES,
Field.Index.ANALYZED));
writer.addDocument(doc);
doc = new Document();
// DOC2
doc.add(new Field("text","dddd aaaa aaaa cccc"));
writer.addDocument(doc);
doc = new Document();
// DOC3
doc.add(new Field("text","dddd aaaa yyyy aaaa xxxx cccc"));
writer.addDocument(doc);
writer.optimize();
writer.close();
searcher = new IndexSearcher(directory, false);
SpanQuery[] clauses = new SpanQuery[2];
clauses[0] = new SpanTermQuery(new Term("text", "aaaa"));
clauses[1] = new SpanTermQuery(new Term("text", "aaaa"));
// Don't care about order, so setting inOrder = false
SpanNearQuery q = new SpanNearQuery(clauses, 1, false);
searcher.search(q, collector);
// This assert fails - 3 docs are returned. Expecting only DOC2 and DOC3
Assert.assertEquals("Check 2 results", 2, collector.getTotalHits());
collector = new TopScoreDocCollector.create(3, false);
clauses = new SpanQuery[2];
clauses[0] = new SpanTermQuery(new Term("text", "aaaa"));
clauses[1] = new SpanTermQuery(new Term("text", "aaaa"));
// Don't care about order, so setting inOrder = false
q = new SpanNearQuery(clauses, 0, false);
searcher.search(q, collector);
// This assert fails - 3 docs are returned. Expecting only DOC2
Assert.assertEquals("Check 1 result", 1, collector.getTotalHits());
}
}
<<TestSpanNearQueryInOrder.java>>
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TestSpanNearQueryInOrder.java
Description: TestSpanNearQueryInOrder.java
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