Lucene example source code file (TestWildcardRandom.java)

This example Lucene source code file (TestWildcardRandom.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, exception, exception, field, field, n, n, n*n, nn, nn, override, randomindexwriter, stringbuilder, term, text, util

The Lucene TestWildcardRandom.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 java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;
import java.text.NumberFormat;
import java.util.Locale;

import org.apache.lucene.analysis.MockAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.RandomIndexWriter;
import org.apache.lucene.index.Term;
import org.apache.lucene.store.Directory;
import org.apache.lucene.util.LuceneTestCase;
import org.apache.lucene.util._TestUtil;

/**
 * Create an index with terms from 000-999.
 * Generates random wildcards according to patterns,
 * and validates the correct number of hits are returned.
 */
public class TestWildcardRandom extends LuceneTestCase {
  private IndexSearcher searcher;
  private IndexReader reader;
  private Directory dir;
  
  @Override
  public void setUp() throws Exception {
    super.setUp();
    dir = newDirectory();
    RandomIndexWriter writer = new RandomIndexWriter(random, dir,
        newIndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(random))
        .setMaxBufferedDocs(_TestUtil.nextInt(random, 50, 1000)));
    
    Document doc = new Document();
    Field bogus1 = newField("bogus1", "", Field.Store.NO, Field.Index.NOT_ANALYZED_NO_NORMS);
    Field field = newField("field", "", Field.Store.NO, Field.Index.ANALYZED_NO_NORMS);
    Field bogus2 = newField("zbogus2", "", Field.Store.NO, Field.Index.NOT_ANALYZED_NO_NORMS);
    doc.add(field);
    doc.add(bogus1);
    doc.add(bogus2);
    
    NumberFormat df = new DecimalFormat("000", new DecimalFormatSymbols(Locale.ENGLISH));
    for (int i = 0; i < 1000; i++) {
      field.setValue(df.format(i));
      bogus1.setValue(_TestUtil.randomUnicodeString(random, 10));
      bogus2.setValue(_TestUtil.randomUnicodeString(random, 10));
      writer.addDocument(doc);
    }
    
    reader = writer.getReader();
    searcher = newSearcher(reader);
    writer.close();
  }
  
  private char N() {
    return (char) (0x30 + random.nextInt(10));
  }
  
  private String fillPattern(String wildcardPattern) {
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < wildcardPattern.length(); i++) {
      switch(wildcardPattern.charAt(i)) {
        case 'N':
          sb.append(N());
          break;
        default:
          sb.append(wildcardPattern.charAt(i));
      }
    }
    return sb.toString();
  }
  
  private void assertPatternHits(String pattern, int numHits) throws Exception {
    // TODO: run with different rewrites
    Query wq = new WildcardQuery(new Term("field", fillPattern(pattern)));
    TopDocs docs = searcher.search(wq, 25);
    assertEquals("Incorrect hits for pattern: " + pattern, numHits, docs.totalHits);
  }

  @Override
  public void tearDown() throws Exception {
    searcher.close();
    reader.close();
    dir.close();
    super.tearDown();
  }
  
  public void testWildcards() throws Exception {;
    int num = atLeast(1);
    for (int i = 0; i < num; i++) {
      assertPatternHits("NNN", 1);
      assertPatternHits("?NN", 10);
      assertPatternHits("N?N", 10);
      assertPatternHits("NN?", 10);
    }
    
    for (int i = 0; i < num; i++) {
      assertPatternHits("??N", 100);
      assertPatternHits("N??", 100);
      assertPatternHits("???", 1000);
      
      assertPatternHits("NN*", 10);
      assertPatternHits("N*", 100);
      assertPatternHits("*", 1000);
      
      assertPatternHits("*NN", 10);
      assertPatternHits("*N", 100);
      
      assertPatternHits("N*N", 10);
      
      // combo of ? and * operators
      assertPatternHits("?N*", 100);
      assertPatternHits("N?*", 100);
      
      assertPatternHits("*N?", 100);
      assertPatternHits("*??", 1000);
      assertPatternHits("*?N", 100);
    }
  }
}