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Lucene example source code file (TestPrefixFilter.java)

This example Lucene source code file (TestPrefixFilter.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

computers, computers/linux, computers/mac/one, computers/windows, constantscorequery, constantscorequery, document, document, prefixfilter, prefixfilter, randomindexwriter, string, term, term

The Lucene TestPrefixFilter.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.util.LuceneTestCase;
import org.apache.lucene.store.Directory;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.RandomIndexWriter;
import org.apache.lucene.index.Term;

import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;

/**
 * Tests {@link PrefixFilter} class.
 *
 */
public class TestPrefixFilter extends LuceneTestCase {
  public void testPrefixFilter() throws Exception {
    Directory directory = newDirectory();

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

    // PrefixFilter combined with ConstantScoreQuery
    PrefixFilter filter = new PrefixFilter(new Term("category", "/Computers"));
    Query query = new ConstantScoreQuery(filter);
    IndexSearcher searcher = newSearcher(reader);
    ScoreDoc[] hits = searcher.search(query, null, 1000).scoreDocs;
    assertEquals(4, hits.length);

    // test middle of values
    filter = new PrefixFilter(new Term("category", "/Computers/Mac"));
    query = new ConstantScoreQuery(filter);
    hits = searcher.search(query, null, 1000).scoreDocs;
    assertEquals(2, hits.length);

    // test start of values
    filter = new PrefixFilter(new Term("category", "/Computers/Linux"));
    query = new ConstantScoreQuery(filter);
    hits = searcher.search(query, null, 1000).scoreDocs;
    assertEquals(1, hits.length);

    // test end of values
    filter = new PrefixFilter(new Term("category", "/Computers/Windows"));
    query = new ConstantScoreQuery(filter);
    hits = searcher.search(query, null, 1000).scoreDocs;
    assertEquals(1, hits.length);

    // test non-existant
    filter = new PrefixFilter(new Term("category", "/Computers/ObsoleteOS"));
    query = new ConstantScoreQuery(filter);
    hits = searcher.search(query, null, 1000).scoreDocs;
    assertEquals(0, hits.length);

    // test non-existant, before values
    filter = new PrefixFilter(new Term("category", "/Computers/AAA"));
    query = new ConstantScoreQuery(filter);
    hits = searcher.search(query, null, 1000).scoreDocs;
    assertEquals(0, hits.length);

    // test non-existant, after values
    filter = new PrefixFilter(new Term("category", "/Computers/ZZZ"));
    query = new ConstantScoreQuery(filter);
    hits = searcher.search(query, null, 1000).scoreDocs;
    assertEquals(0, hits.length);

    // test zero length prefix
    filter = new PrefixFilter(new Term("category", ""));
    query = new ConstantScoreQuery(filter);
    hits = searcher.search(query, null, 1000).scoreDocs;
    assertEquals(4, hits.length);

    // test non existent field
    filter = new PrefixFilter(new Term("nonexistantfield", "/Computers"));
    query = new ConstantScoreQuery(filter);
    hits = searcher.search(query, null, 1000).scoreDocs;
    assertEquals(0, hits.length);
    
    writer.close();
    searcher.close();
    reader.close();
    directory.close();
  }
}

Other Lucene examples (source code examples)

Here is a short list of links related to this Lucene TestPrefixFilter.java source code file:

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