HighlightTest.java

package lia.tools;

/**
 * Copyright Manning Publications Co.
 *
 * Licensed 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 lan      
*/

import junit.framework.TestCase;
import lia.common.TestUtil;

import org.apache.lucene.analysis.SimpleAnalyzer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.index.Term;
import org.apache.lucene.document.Document;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.search.highlight.Highlighter;
import org.apache.lucene.search.highlight.QueryScorer;
import org.apache.lucene.search.highlight.TokenSources;
import org.apache.lucene.search.highlight.SimpleSpanFragmenter;
import org.apache.lucene.search.highlight.Fragmenter;

import java.io.StringReader;

// From chapter 8
public class HighlightTest extends TestCase {
  public void testHighlighting() throws Exception {
    String text = "The quick brown fox jumps over the lazy dog";

    TermQuery query = new TermQuery(new Term("field", "fox"));

    TokenStream tokenStream =
        new SimpleAnalyzer().tokenStream("field",
            new StringReader(text));

    QueryScorer scorer = new QueryScorer(query, "field");
    Fragmenter fragmenter = new SimpleSpanFragmenter(scorer);
    Highlighter highlighter = new Highlighter(scorer);
    highlighter.setTextFragmenter(fragmenter);
    assertEquals("The quick brown <B>fox</B> jumps over the lazy dog",
        highlighter.getBestFragment(tokenStream, text));
  }

  public void testHits() throws Exception {
    IndexSearcher searcher = new IndexSearcher(TestUtil.getBookIndexDirectory());
    TermQuery query = new TermQuery(new Term("title", "action"));
    TopDocs hits = searcher.search(query, 10);

    QueryScorer scorer = new QueryScorer(query, "title");
    Highlighter highlighter = new Highlighter(scorer);
    highlighter.setTextFragmenter(
                   new SimpleSpanFragmenter(scorer));
      
    Analyzer analyzer = new SimpleAnalyzer();
    
    for (ScoreDoc sd : hits.scoreDocs) {
      Document doc = searcher.doc(sd.doc);
      String title = doc.get("title");

      TokenStream stream = TokenSources.getAnyTokenStream(searcher.getIndexReader(),
                                                          sd.doc,
                                                          "title",
                                                          doc,
                                                          analyzer);
      String fragment =
          highlighter.getBestFragment(stream, title);

      System.out.println(fragment);
    }
  }

}