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Lucene example source code file (TestSearchForDuplicates.java)

This example Lucene source code file (TestSearchForDuplicates.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Lucene tags/keywords

document, document, io, max_docs, max_docs, med_priority, printwriter, printwriter, priority_field, query, queryparser, searcher, string, string, stringwriter, util

The Lucene TestSearchForDuplicates.java source code

package org.apache.lucene;

 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *     http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * See the License for the specific language governing permissions and
 * limitations under the License.

import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.Random;

import org.apache.lucene.store.*;
import org.apache.lucene.document.*;
import org.apache.lucene.analysis.*;
import org.apache.lucene.index.*;
import org.apache.lucene.search.*;
import org.apache.lucene.queryParser.*;
import org.apache.lucene.util.LuceneTestCase;
import junit.framework.TestSuite;
import junit.textui.TestRunner;

public class TestSearchForDuplicates extends LuceneTestCase {

    /** Main for running test case by itself. */
    public static void main(String args[]) {
        TestRunner.run (new TestSuite(TestSearchForDuplicates.class));

  static final String PRIORITY_FIELD ="priority";
  static final String ID_FIELD ="id";
  static final String HIGH_PRIORITY ="high";
  static final String MED_PRIORITY ="medium";
  static final String LOW_PRIORITY ="low";

  /** This test compares search results when using and not using compound
   *  files.
   *  TODO: There is rudimentary search result validation as well, but it is
   *        simply based on asserting the output observed in the old test case,
   *        without really knowing if the output is correct. Someone needs to
   *        validate this output and make any changes to the checkHits method.
  public void testRun() throws Exception {
      StringWriter sw = new StringWriter();
      PrintWriter pw = new PrintWriter(sw, true);
      doTest(random, pw, false);
      String multiFileOutput = sw.getBuffer().toString();

      sw = new StringWriter();
      pw = new PrintWriter(sw, true);
      doTest(random, pw, true);
      String singleFileOutput = sw.getBuffer().toString();

      assertEquals(multiFileOutput, singleFileOutput);

  private void doTest(Random random, PrintWriter out, boolean useCompoundFiles) throws Exception {
      Directory directory = newDirectory();
      Analyzer analyzer = new MockAnalyzer(random);
      IndexWriterConfig conf = newIndexWriterConfig(TEST_VERSION_CURRENT, analyzer);
      final MergePolicy mp = conf.getMergePolicy();
      if (mp instanceof LogMergePolicy) {
        ((LogMergePolicy) mp).setUseCompoundFile(useCompoundFiles);
      IndexWriter writer = new IndexWriter(directory, conf);
      if (VERBOSE) {
        System.out.println("TEST: now build index");

      final int MAX_DOCS = 225;

      for (int j = 0; j < MAX_DOCS; j++) {
        Document d = new Document();
        d.add(newField(PRIORITY_FIELD, HIGH_PRIORITY, Field.Store.YES, Field.Index.ANALYZED));
        d.add(newField(ID_FIELD, Integer.toString(j), Field.Store.YES, Field.Index.ANALYZED));

      // try a search without OR
      Searcher searcher = new IndexSearcher(directory, true);

      QueryParser parser = new QueryParser(TEST_VERSION_CURRENT, PRIORITY_FIELD, analyzer);

      Query query = parser.parse(HIGH_PRIORITY);
      out.println("Query: " + query.toString(PRIORITY_FIELD));

      final Sort sort = new Sort(new SortField[] {
          new SortField(ID_FIELD, SortField.INT)});

      ScoreDoc[] hits = searcher.search(query, null, MAX_DOCS, sort).scoreDocs;
      printHits(out, hits, searcher);
      checkHits(hits, MAX_DOCS, searcher);


      // try a new search with OR
      searcher = new IndexSearcher(directory, true);
      hits = null;

      parser = new QueryParser(TEST_VERSION_CURRENT, PRIORITY_FIELD, analyzer);

      query = parser.parse(HIGH_PRIORITY + " OR " + MED_PRIORITY);
      out.println("Query: " + query.toString(PRIORITY_FIELD));

      hits = searcher.search(query, null, MAX_DOCS, sort).scoreDocs;
      printHits(out, hits, searcher);
      checkHits(hits, MAX_DOCS, searcher);


  private void printHits(PrintWriter out, ScoreDoc[] hits, Searcher searcher ) throws IOException {
    out.println(hits.length + " total results\n");
    for (int i = 0 ; i < hits.length; i++) {
      if ( i < 10 || (i > 94 && i < 105) ) {
        Document d = searcher.doc(hits[i].doc);
        out.println(i + " " + d.get(ID_FIELD));

  private void checkHits(ScoreDoc[] hits, int expectedCount, Searcher searcher) throws IOException {
    assertEquals("total results", expectedCount, hits.length);
    for (int i = 0 ; i < hits.length; i++) {
      if (i < 10 || (i > 94 && i < 105) ) {
      Document d = searcher.doc(hits[i].doc);
        assertEquals("check " + i, String.valueOf(i), d.get(ID_FIELD));


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