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Lucene example source code file (TestWildcard.java)

This example Lucene source code file (TestWildcard.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

booleanquery, directory, indexsearcher, io, ioexception, query, query, randomindexwriter, scoredoc, string, string, term, term, wildcardquery, wildcardquery

The Lucene TestWildcard.java source code

package org.apache.lucene.search;

/**
 * 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,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import org.apache.lucene.store.Directory;
import org.apache.lucene.util.LuceneTestCase;
import org.apache.lucene.analysis.MockAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.Field.Store;
import org.apache.lucene.document.Field.Index;
import org.apache.lucene.index.RandomIndexWriter;
import org.apache.lucene.index.Term;
import org.apache.lucene.queryParser.QueryParser;

import java.io.IOException;

/**
 * TestWildcard tests the '*' and '?' wildcard characters.
 */
public class TestWildcard
    extends LuceneTestCase {
  
  @Override
  public void setUp() throws Exception {
    super.setUp();
  }

  public void testEquals() {
    WildcardQuery wq1 = new WildcardQuery(new Term("field", "b*a"));
    WildcardQuery wq2 = new WildcardQuery(new Term("field", "b*a"));
    WildcardQuery wq3 = new WildcardQuery(new Term("field", "b*a"));

    // reflexive?
    assertEquals(wq1, wq2);
    assertEquals(wq2, wq1);

    // transitive?
    assertEquals(wq2, wq3);
    assertEquals(wq1, wq3);

    assertFalse(wq1.equals(null));

    FuzzyQuery fq = new FuzzyQuery(new Term("field", "b*a"));
    assertFalse(wq1.equals(fq));
    assertFalse(fq.equals(wq1));
  }
  
  /**
   * Tests if a WildcardQuery that has no wildcard in the term is rewritten to a single
   * TermQuery. The boost should be preserved, and the rewrite should return
   * a ConstantScoreQuery if the WildcardQuery had a ConstantScore rewriteMethod.
   */
  public void testTermWithoutWildcard() throws IOException {
      Directory indexStore = getIndexStore("field", new String[]{"nowildcard", "nowildcardx"});
      IndexSearcher searcher = new IndexSearcher(indexStore, true);

      MultiTermQuery wq = new WildcardQuery(new Term("field", "nowildcard"));
      assertMatches(searcher, wq, 1);

      wq.setRewriteMethod(MultiTermQuery.SCORING_BOOLEAN_QUERY_REWRITE);
      wq.setBoost(0.1F);
      Query q = searcher.rewrite(wq);
      assertTrue(q instanceof TermQuery);
      assertEquals(q.getBoost(), wq.getBoost());
      
      wq.setRewriteMethod(MultiTermQuery.CONSTANT_SCORE_FILTER_REWRITE);
      wq.setBoost(0.2F);
      q = searcher.rewrite(wq);
      assertTrue(q instanceof ConstantScoreQuery);
      assertEquals(q.getBoost(), wq.getBoost());
      
      wq.setRewriteMethod(MultiTermQuery.CONSTANT_SCORE_AUTO_REWRITE_DEFAULT);
      wq.setBoost(0.3F);
      q = searcher.rewrite(wq);
      assertTrue(q instanceof ConstantScoreQuery);
      assertEquals(q.getBoost(), wq.getBoost());
      
      wq.setRewriteMethod(MultiTermQuery.CONSTANT_SCORE_BOOLEAN_QUERY_REWRITE);
      wq.setBoost(0.4F);
      q = searcher.rewrite(wq);
      assertTrue(q instanceof ConstantScoreQuery);
      assertEquals(q.getBoost(), wq.getBoost());
      searcher.close();
      indexStore.close();
  }
  
  /**
   * Tests if a WildcardQuery with an empty term is rewritten to an empty BooleanQuery
   */
  public void testEmptyTerm() throws IOException {
    Directory indexStore = getIndexStore("field", new String[]{"nowildcard", "nowildcardx"});
    IndexSearcher searcher = new IndexSearcher(indexStore, true);

    MultiTermQuery wq = new WildcardQuery(new Term("field", ""));
    wq.setRewriteMethod(MultiTermQuery.SCORING_BOOLEAN_QUERY_REWRITE);
    assertMatches(searcher, wq, 0);
    Query q = searcher.rewrite(wq);
    assertTrue(q instanceof BooleanQuery);
    assertEquals(0, ((BooleanQuery) q).clauses().size());
    searcher.close();
    indexStore.close();
  }
  
  /**
   * Tests Wildcard queries with an asterisk.
   */
  public void testAsterisk()
      throws IOException {
    Directory indexStore = getIndexStore("body", new String[]
    {"metal", "metals"});
    IndexSearcher searcher = new IndexSearcher(indexStore, true);
    Query query1 = new TermQuery(new Term("body", "metal"));
    Query query2 = new WildcardQuery(new Term("body", "metal*"));
    Query query3 = new WildcardQuery(new Term("body", "m*tal"));
    Query query4 = new WildcardQuery(new Term("body", "m*tal*"));
    Query query5 = new WildcardQuery(new Term("body", "m*tals"));

    BooleanQuery query6 = new BooleanQuery();
    query6.add(query5, BooleanClause.Occur.SHOULD);

    BooleanQuery query7 = new BooleanQuery();
    query7.add(query3, BooleanClause.Occur.SHOULD);
    query7.add(query5, BooleanClause.Occur.SHOULD);

    // Queries do not automatically lower-case search terms:
    Query query8 = new WildcardQuery(new Term("body", "M*tal*"));

    assertMatches(searcher, query1, 1);
    assertMatches(searcher, query2, 2);
    assertMatches(searcher, query3, 1);
    assertMatches(searcher, query4, 2);
    assertMatches(searcher, query5, 1);
    assertMatches(searcher, query6, 1);
    assertMatches(searcher, query7, 2);
    assertMatches(searcher, query8, 0);
    assertMatches(searcher, new WildcardQuery(new Term("body", "*tall")), 0);
    assertMatches(searcher, new WildcardQuery(new Term("body", "*tal")), 1);
    assertMatches(searcher, new WildcardQuery(new Term("body", "*tal*")), 2);
    searcher.close();
    indexStore.close();
  }

  /**
   * LUCENE-2620
   */
  public void testLotsOfAsterisks()
      throws IOException {
    Directory indexStore = getIndexStore("body", new String[]
    {"metal", "metals"});
    IndexSearcher searcher = new IndexSearcher(indexStore, true);
    StringBuilder term = new StringBuilder();
    term.append("m");
    for (int i = 0; i < 512; i++)
      term.append("*");
    term.append("tal");
    Query query3 = new WildcardQuery(new Term("body", term.toString()));

    assertMatches(searcher, query3, 1);
    searcher.close();
    indexStore.close();
  }
  
  /**
   * Tests Wildcard queries with a question mark.
   *
   * @throws IOException if an error occurs
   */
  public void testQuestionmark()
      throws IOException {
    Directory indexStore = getIndexStore("body", new String[]
    {"metal", "metals", "mXtals", "mXtXls"});
    IndexSearcher searcher = new IndexSearcher(indexStore, true);
    Query query1 = new WildcardQuery(new Term("body", "m?tal"));
    Query query2 = new WildcardQuery(new Term("body", "metal?"));
    Query query3 = new WildcardQuery(new Term("body", "metals?"));
    Query query4 = new WildcardQuery(new Term("body", "m?t?ls"));
    Query query5 = new WildcardQuery(new Term("body", "M?t?ls"));
    Query query6 = new WildcardQuery(new Term("body", "meta??"));
    
    assertMatches(searcher, query1, 1); 
    assertMatches(searcher, query2, 1);
    assertMatches(searcher, query3, 0);
    assertMatches(searcher, query4, 3);
    assertMatches(searcher, query5, 0);
    assertMatches(searcher, query6, 1); // Query: 'meta??' matches 'metals' not 'metal'
    searcher.close();
    indexStore.close();
  }

  private Directory getIndexStore(String field, String[] contents)
      throws IOException {
    Directory indexStore = newDirectory();
    RandomIndexWriter writer = new RandomIndexWriter(random, indexStore);
    for (int i = 0; i < contents.length; ++i) {
      Document doc = new Document();
      doc.add(newField(field, contents[i], Field.Store.YES, Field.Index.ANALYZED));
      writer.addDocument(doc);
    }
    writer.close();

    return indexStore;
  }

  private void assertMatches(IndexSearcher searcher, Query q, int expectedMatches)
      throws IOException {
    ScoreDoc[] result = searcher.search(q, null, 1000).scoreDocs;
    assertEquals(expectedMatches, result.length);
  }

  /**
   * Test that wild card queries are parsed to the correct type and are searched correctly.
   * This test looks at both parsing and execution of wildcard queries.
   * Although placed here, it also tests prefix queries, verifying that
   * prefix queries are not parsed into wild card queries, and viceversa.
   * @throws Exception
   */
  public void testParsingAndSearching() throws Exception {
    String field = "content";
    QueryParser qp = new QueryParser(TEST_VERSION_CURRENT, field, new MockAnalyzer(random));
    qp.setAllowLeadingWildcard(true);
    String docs[] = {
        "\\ abcdefg1",
        "\\79 hijklmn1",
        "\\\\ opqrstu1",
    };
    // queries that should find all docs
    String matchAll[] = {
        "*", "*1", "**1", "*?", "*?1", "?*1", "**", "***", "\\\\*"
    };
    // queries that should find no docs
    String matchNone[] = {
        "a*h", "a?h", "*a*h", "?a", "a?",
    };
    // queries that should be parsed to prefix queries
    String matchOneDocPrefix[][] = {
        {"a*", "ab*", "abc*", }, // these should find only doc 0 
        {"h*", "hi*", "hij*", "\\\\7*"}, // these should find only doc 1
        {"o*", "op*", "opq*", "\\\\\\\\*"}, // these should find only doc 2
    };
    // queries that should be parsed to wildcard queries
    String matchOneDocWild[][] = {
        {"*a*", "*ab*", "*abc**", "ab*e*", "*g?", "*f?1", "abc**"}, // these should find only doc 0
        {"*h*", "*hi*", "*hij**", "hi*k*", "*n?", "*m?1", "hij**"}, // these should find only doc 1
        {"*o*", "*op*", "*opq**", "op*q*", "*u?", "*t?1", "opq**"}, // these should find only doc 2
    };

    // prepare the index
    Directory dir = newDirectory();
    RandomIndexWriter iw = new RandomIndexWriter(random, dir, 
        newIndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(random))
        .setMergePolicy(newLogMergePolicy()));
    for (int i = 0; i < docs.length; i++) {
      Document doc = new Document();
      doc.add(newField(field,docs[i],Store.NO,Index.ANALYZED));
      iw.addDocument(doc);
    }
    iw.close();
    
    IndexSearcher searcher = new IndexSearcher(dir, true);
    
    // test queries that must find all
    for (int i = 0; i < matchAll.length; i++) {
      String qtxt = matchAll[i];
      Query q = qp.parse(qtxt);
      if (VERBOSE) System.out.println("matchAll: qtxt="+qtxt+" q="+q+" "+q.getClass().getName());
      ScoreDoc[] hits = searcher.search(q, null, 1000).scoreDocs;
      assertEquals(docs.length,hits.length);
    }
    
    // test queries that must find none
    for (int i = 0; i < matchNone.length; i++) {
      String qtxt = matchNone[i];
      Query q = qp.parse(qtxt);
      if (VERBOSE) System.out.println("matchNone: qtxt="+qtxt+" q="+q+" "+q.getClass().getName());
      ScoreDoc[] hits = searcher.search(q, null, 1000).scoreDocs;
      assertEquals(0,hits.length);
    }

    // test queries that must be prefix queries and must find only one doc
    for (int i = 0; i < matchOneDocPrefix.length; i++) {
      for (int j = 0; j < matchOneDocPrefix[i].length; j++) {
        String qtxt = matchOneDocPrefix[i][j];
        Query q = qp.parse(qtxt);
        if (VERBOSE) System.out.println("match 1 prefix: doc="+docs[i]+" qtxt="+qtxt+" q="+q+" "+q.getClass().getName());
        assertEquals(PrefixQuery.class, q.getClass());
        ScoreDoc[] hits = searcher.search(q, null, 1000).scoreDocs;
        assertEquals(1,hits.length);
        assertEquals(i,hits[0].doc);
      }
    }

    // test queries that must be wildcard queries and must find only one doc
    for (int i = 0; i < matchOneDocPrefix.length; i++) {
      for (int j = 0; j < matchOneDocWild[i].length; j++) {
        String qtxt = matchOneDocWild[i][j];
        Query q = qp.parse(qtxt);
        if (VERBOSE) System.out.println("match 1 wild: doc="+docs[i]+" qtxt="+qtxt+" q="+q+" "+q.getClass().getName());
        assertEquals(WildcardQuery.class, q.getClass());
        ScoreDoc[] hits = searcher.search(q, null, 1000).scoreDocs;
        assertEquals(1,hits.length);
        assertEquals(i,hits[0].doc);
      }
    }

    searcher.close();
    dir.close();
  }
  
}

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