lucene/core/src/test/org/apache/lucene/search/TestPrefixQuery.java

/*
 * 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.
 */
package org.apache.lucene.search;


import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

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.BytesRef;
import org.apache.lucene.util.LuceneTestCase;
import org.apache.lucene.util.StringHelper;
import org.apache.lucene.util.TestUtil;

/**
 * Tests {@link PrefixQuery} class.
 *
 */
public class TestPrefixQuery extends LuceneTestCase {
  public void testPrefixQuery() throws Exception {
    Directory directory = newDirectory();

    String[] categories = new String[] {"/Computers",
                                        "/Computers/Mac",
                                        "/Computers/Windows"};
    RandomIndexWriter writer = new RandomIndexWriter(random(), directory);
    for (int i = 0; i < categories.length; i++) {
      Document doc = new Document();
      doc.add(newStringField("category", categories[i], Field.Store.YES));
      writer.addDocument(doc);
    }
    IndexReader reader = writer.getReader();

    PrefixQuery query = new PrefixQuery(new Term("category", "/Computers"));
    IndexSearcher searcher = newSearcher(reader);
    ScoreDoc[] hits = searcher.search(query, 1000).scoreDocs;
    assertEquals("All documents in /Computers category and below", 3, hits.length);

    query = new PrefixQuery(new Term("category", "/Computers/Mac"));
    hits = searcher.search(query, 1000).scoreDocs;
    assertEquals("One in /Computers/Mac", 1, hits.length);

    query = new PrefixQuery(new Term("category", ""));
    hits = searcher.search(query, 1000).scoreDocs;
    assertEquals("everything", 3, hits.length);
    writer.close();
    reader.close();
    directory.close();
  }

  public void testMatchAll() throws Exception {
    Directory directory = newDirectory();

    RandomIndexWriter writer = new RandomIndexWriter(random(), directory);
    Document doc = new Document();
    doc.add(newStringField("field", "field", Field.Store.YES));
    writer.addDocument(doc);

    IndexReader reader = writer.getReader();

    PrefixQuery query = new PrefixQuery(new Term("field", ""));
    IndexSearcher searcher = newSearcher(reader);

    assertEquals(1, searcher.search(query, 1000).totalHits.value);
    writer.close();
    reader.close();
    directory.close();
  }

  public void testRandomBinaryPrefix() throws Exception {
    Directory dir = newDirectory();
    RandomIndexWriter w = new RandomIndexWriter(random(), dir);

    int numTerms = atLeast(1000);
    Set<BytesRef> terms = new HashSet<>();
    while (terms.size() < numTerms) {
      byte[] bytes = new byte[TestUtil.nextInt(random(), 1, 10)];
      random().nextBytes(bytes);
      terms.add(new BytesRef(bytes));
    }

    List<BytesRef> termsList = new ArrayList<>(terms);  
    Collections.shuffle(termsList, random());
    for(BytesRef term : termsList) {
      Document doc = new Document();
      doc.add(newStringField("field", term, Field.Store.NO));
      w.addDocument(doc);
    }

    IndexReader r = w.getReader();
    IndexSearcher s = newSearcher(r);

    int iters = atLeast(100);   
    for(int iter=0;iter<iters;iter++) {
      byte[] bytes = new byte[random().nextInt(3)];
      random().nextBytes(bytes);
      BytesRef prefix = new BytesRef(bytes);
      PrefixQuery q = new PrefixQuery(new Term("field", prefix));
      int count = 0;
      for(BytesRef term : termsList) {
        if (StringHelper.startsWith(term, prefix)) {
          count++;
        }
      }
      assertEquals(count, s.count(q));
    }
    r.close();
    w.close();
    dir.close();
  }
}