Custom filters and booleanquery (MUST_NOT)

[Amrit Jassal]

I am experimenting with using a custom filter with QueryParser and ran into
some unanticipated issues with using NOT terms. I narrowed down the issue
into the following test case. I am expecting a MUST_NOT booleanclause within
a booleanquery to return a resultset that is the complement of a MUST
clause. Can filters not be used for negative queries (such as "-term:xxx")
like this?

BTW I have checked with the latest SVN codebase as well.

Thanks for any hints...

=====

import java.io.IOException;
import java.util.BitSet;
import java.util.Iterator;

import org.apache.lucene.analysis.SimpleAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.search.BooleanClause;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.Filter;
import org.apache.lucene.search.FilteredQuery;
import org.apache.lucene.search.Hit;
import org.apache.lucene.search.Hits;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.MatchAllDocsQuery;
import org.apache.lucene.store.RAMDirectory;

import junit.framework.TestCase;

public class FilteredQueryTest extends TestCase {
    private class MyFilter extends Filter {
        MyFilter(BitSet bits) {
            this.bits= bits;
        }
        @Override
        public BitSet bits(IndexReader arg0) throws IOException {
            return this.bits;
        }
        private BitSet bits;
    }
    public void setUp() throws Exception {
        RAMDirectory indexStore = new RAMDirectory ();
        IndexWriter writer = new IndexWriter (indexStore, new
SimpleAnalyzer(), true);
        Document doc = new Document();
        doc.add(new Field("tag", "t1", Field.Store.YES,
Field.Index.UN_TOKENIZED));
        writer.addDocument(doc);
        doc = new Document();
        doc.add(new Field("tag", "t2", Field.Store.YES,
Field.Index.UN_TOKENIZED));
        writer.addDocument(doc);
        writer.optimize ();
        writer.close();
        this.searcher = new IndexSearcher (indexStore);
    }

    public void testFilter() {
        try {
            BitSet bits = new BitSet(this.searcher.maxDoc());
            bits.set(1);
            FilteredQuery fq = new FilteredQuery(new MatchAllDocsQuery(),
new MyFilter(bits));
            BooleanQuery bquery = new BooleanQuery();
            bquery.add(new BooleanClause(fq, BooleanClause.Occur.MUST));
            Hits hits = this.searcher.search(bquery);
            assertTrue(hits.length() == 1);
            for (Iterator h = hits.iterator(); h.hasNext(); ) {
                assertTrue(((Hit)h.next()).getId() == 1);
            }
            bquery = new BooleanQuery();
            bquery.add(new BooleanClause(fq, BooleanClause.Occur.MUST_NOT));
            hits = this.searcher.search(bquery);
            assertTrue(hits.length() == 1);       // <<<<<<<<< returns 0,
expecting doc #2 (t2) to return...
            for (Iterator h = hits.iterator(); h.hasNext(); ) {
                assertTrue(((Hit)h.next()).getId() == 2);
            }
        } catch (Exception e) {
            e.printStackTrace();
            fail();
        }
    }

    private IndexSearcher searcher;
}