home | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Lucene example source code file (SortedTermVectorMapper.java)

This example Lucene source code file (SortedTermVectorMapper.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

all, comparator, override, sortedset, sortedset, sortedtermvectormapper, sortedtermvectormapper, string, termvectorentry, termvectorentry, termvectormapper, termvectoroffsetinfo, termvectoroffsetinfo, treeset, util

The Lucene SortedTermVectorMapper.java source code

package org.apache.lucene.index;
/**
 * Copyright 2007 The Apache Software Foundation
 *
 * 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 language governing permissions and
 * limitations under the License.
 */

import java.util.*;

/**
 * Store a sorted collection of {@link org.apache.lucene.index.TermVectorEntry}s.  Collects all term information
 * into a single, SortedSet.
 * <br/>
 * NOTE: This Mapper ignores all Field information for the Document.  This means that if you are using offset/positions you will not
 * know what Fields they correlate with.
 *  <br/>
 * This is not thread-safe  
 */
public class SortedTermVectorMapper extends TermVectorMapper{


  private SortedSet<TermVectorEntry> currentSet;
  private Map<String,TermVectorEntry> termToTVE = new HashMap();
  private boolean storeOffsets;
  private boolean storePositions;
  /**
   * Stand-in name for the field in {@link TermVectorEntry}.
   */
  public static final String ALL = "_ALL_";

  /**
   *
   * @param comparator A Comparator for sorting {@link TermVectorEntry}s
   */
  public SortedTermVectorMapper(Comparator<TermVectorEntry> comparator) {
    this(false, false, comparator);
  }


  public SortedTermVectorMapper(boolean ignoringPositions, boolean ignoringOffsets, Comparator<TermVectorEntry> comparator) {
    super(ignoringPositions, ignoringOffsets);
    currentSet = new TreeSet<TermVectorEntry>(comparator);
  }

  /**
   *
   * @param term The term to map
   * @param frequency The frequency of the term
   * @param offsets Offset information, may be null
   * @param positions Position information, may be null
   */
  //We need to combine any previous mentions of the term
  @Override
  public void map(String term, int frequency, TermVectorOffsetInfo[] offsets, int[] positions) {
    TermVectorEntry entry =  termToTVE.get(term);
    if (entry == null) {
      entry = new TermVectorEntry(ALL, term, frequency, 
              storeOffsets == true ? offsets : null,
              storePositions == true ? positions : null);
      termToTVE.put(term, entry);
      currentSet.add(entry);
    } else {
      entry.setFrequency(entry.getFrequency() + frequency);
      if (storeOffsets)
      {
        TermVectorOffsetInfo [] existingOffsets = entry.getOffsets();
        //A few diff. cases here:  offsets is null, existing offsets is null, both are null, same for positions
        if (existingOffsets != null && offsets != null && offsets.length > 0)
        {
          //copy over the existing offsets
          TermVectorOffsetInfo [] newOffsets = new TermVectorOffsetInfo[existingOffsets.length + offsets.length];
          System.arraycopy(existingOffsets, 0, newOffsets, 0, existingOffsets.length);
          System.arraycopy(offsets, 0, newOffsets, existingOffsets.length, offsets.length);
          entry.setOffsets(newOffsets);
        }
        else if (existingOffsets == null && offsets != null && offsets.length > 0)
        {
          entry.setOffsets(offsets);
        }
        //else leave it alone
      }
      if (storePositions)
      {
        int [] existingPositions = entry.getPositions();
        if (existingPositions != null && positions != null && positions.length > 0)
        {
          int [] newPositions = new int[existingPositions.length + positions.length];
          System.arraycopy(existingPositions, 0, newPositions, 0, existingPositions.length);
          System.arraycopy(positions, 0, newPositions, existingPositions.length, positions.length);
          entry.setPositions(newPositions);
        }
        else if (existingPositions == null && positions != null && positions.length > 0)
        {
          entry.setPositions(positions);
        }
      }
    }


  }

  @Override
  public void setExpectations(String field, int numTerms, boolean storeOffsets, boolean storePositions) {

    this.storeOffsets = storeOffsets;
    this.storePositions = storePositions;
  }

  /**
   * The TermVectorEntrySet.  A SortedSet of {@link TermVectorEntry} objects.  Sort is by the comparator passed into the constructor.
   *<br/>
   * This set will be empty until after the mapping process takes place.
   *
   * @return The SortedSet of {@link TermVectorEntry}.
   */
  public SortedSet<TermVectorEntry> getTermVectorEntrySet()
  {
    return currentSet;
  }

}

Other Lucene examples (source code examples)

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



my book on functional programming

 

new blog posts

 

Copyright 1998-2019 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.