Lucene example source code file (SearchTravRetHighlightTask.java)

This example Lucene source code file (SearchTravRetHighlightTask.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

benchmarkhighlighter, collection, collection, document, exception, exception, hashset, highlighter, override, override, searchtravrethighlighttask, set, string, string, util

The Lucene SearchTravRetHighlightTask.java source code

package org.apache.lucene.benchmark.byTask.tasks;

/**
 * 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.analysis.Analyzer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.benchmark.byTask.PerfRunData;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.highlight.Highlighter;
import org.apache.lucene.search.highlight.QueryScorer;
import org.apache.lucene.search.highlight.SimpleHTMLFormatter;
import org.apache.lucene.search.highlight.TextFragment;
import org.apache.lucene.search.highlight.TokenSources;

import java.util.Set;
import java.util.Collection;
import java.util.HashSet;
import java.util.Collections;

/**
 * Search and Traverse and Retrieve docs task.  Highlight the fields in the retrieved documents.
 *
 * Uses the {@link org.apache.lucene.search.highlight.SimpleHTMLFormatter} for formatting.
 *
 * <p>Note: This task reuses the reader if it is already open.
 * Otherwise a reader is opened at start and closed at the end.
 * </p>
 *
 * <p>Takes optional multivalued, comma separated param string as: size[<traversal size>],highlight[<int>],maxFrags[<int>],mergeContiguous[<boolean>],fields[name1;name2;...]

 * <ul>
 * <li>traversal size - The number of hits to traverse, otherwise all will be traversed
 * <li>highlight - The number of the hits to highlight.  Will always be less than or equal to traversal size.  Default is Integer.MAX_VALUE (i.e. hits.length())
 * <li>maxFrags - The maximum number of fragments to score by the highlighter
 * <li>mergeContiguous - true if contiguous fragments should be merged.
 * <li>fields - The fields to highlight.  If not specified all fields will be highlighted (or at least attempted)
 * </ul>
 * Example:
 * <pre>"SearchHlgtSameRdr" SearchTravRetHighlight(size[10],highlight[10],mergeContiguous[true],maxFrags[3],fields[body]) > : 1000
 * </pre>
 *
 * Documents must be stored in order for this task to work.  Additionally, term vector positions can be used as well.
 *
 * <p>Other side effects: counts additional 1 (record) for each traversed hit,
 * and 1 more for each retrieved (non null) document and 1 for each fragment returned.</p>
 */
public class SearchTravRetHighlightTask extends SearchTravTask {

  protected int numToHighlight = Integer.MAX_VALUE;
  protected boolean mergeContiguous;
  protected int maxFrags = 2;
  protected Set<String> paramFields = Collections.emptySet();
  protected Highlighter highlighter;
  protected int maxDocCharsToAnalyze;

  public SearchTravRetHighlightTask(PerfRunData runData) {
    super(runData);
  }

  @Override
  public void setup() throws Exception {
    super.setup();
    //check to make sure either the doc is being stored
    PerfRunData data = getRunData();
    if (data.getConfig().get("doc.stored", false) == false){
      throw new Exception("doc.stored must be set to true");
    }
    maxDocCharsToAnalyze = data.getConfig().get("highlighter.maxDocCharsToAnalyze", Highlighter.DEFAULT_MAX_CHARS_TO_ANALYZE);
  }

  @Override
  public boolean withRetrieve() {
    return true;
  }

  @Override
  public int numToHighlight() {
    return numToHighlight;
  }
  
  @Override
  protected BenchmarkHighlighter getBenchmarkHighlighter(Query q){
    highlighter = new Highlighter(new SimpleHTMLFormatter(), new QueryScorer(q));
    highlighter.setMaxDocCharsToAnalyze(maxDocCharsToAnalyze);
    return new BenchmarkHighlighter(){
      @Override
      public int doHighlight(IndexReader reader, int doc, String field,
          Document document, Analyzer analyzer, String text) throws Exception {
        TokenStream ts = TokenSources.getAnyTokenStream(reader, doc, field, document, analyzer);
        TextFragment[] frag = highlighter.getBestTextFragments(ts, text, mergeContiguous, maxFrags);
        return frag != null ? frag.length : 0;
      }
    };
  }

  @Override
  protected Collection<String> getFieldsToHighlight(Document document) {
    Collection<String> result = super.getFieldsToHighlight(document);
    //if stored is false, then result will be empty, in which case just get all the param fields
    if (paramFields.isEmpty() == false && result.isEmpty() == false) {
      result.retainAll(paramFields);
    } else {
      result = paramFields;
    }
    return result;
  }

  @Override
  public void setParams(String params) {
    // can't call super because super doesn't understand our
    // params syntax
    this.params = params;
    String [] splits = params.split(",");
    for (int i = 0; i < splits.length; i++) {
      if (splits[i].startsWith("size[") == true){
        traversalSize = (int)Float.parseFloat(splits[i].substring("size[".length(),splits[i].length() - 1));
      } else if (splits[i].startsWith("highlight[") == true){
        numToHighlight = (int)Float.parseFloat(splits[i].substring("highlight[".length(),splits[i].length() - 1));
      } else if (splits[i].startsWith("maxFrags[") == true){
        maxFrags = (int)Float.parseFloat(splits[i].substring("maxFrags[".length(),splits[i].length() - 1));
      } else if (splits[i].startsWith("mergeContiguous[") == true){
        mergeContiguous = Boolean.valueOf(splits[i].substring("mergeContiguous[".length(),splits[i].length() - 1)).booleanValue();
      } else if (splits[i].startsWith("fields[") == true){
        paramFields = new HashSet<String>();
        String fieldNames = splits[i].substring("fields[".length(), splits[i].length() - 1);
        String [] fieldSplits = fieldNames.split(";");
        for (int j = 0; j < fieldSplits.length; j++) {
          paramFields.add(fieldSplits[j]);          
        }

      }
    }
  }


}