Lucene example source code file (FieldFragList.java)

This example Lucene source code file (FieldFragList.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

arraylist, fieldfraglist, list, list, override, string, string, stringbuilder, stringbuilder, subinfo, subinfo, toffs, util, weightedfraginfo, weightedphraseinfo

The Lucene FieldFragList.java source code

package org.apache.lucene.search.vectorhighlight;

/**
 * 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 java.util.ArrayList;
import java.util.List;

import org.apache.lucene.search.vectorhighlight.FieldPhraseList.WeightedPhraseInfo;
import org.apache.lucene.search.vectorhighlight.FieldPhraseList.WeightedPhraseInfo.Toffs;

/**
 * FieldFragList has a list of "frag info" that is used by FragmentsBuilder class
 * to create fragments (snippets).
 */
public class FieldFragList {

  private List<WeightedFragInfo> fragInfos = new ArrayList();

  /**
   * a constructor.
   * 
   * @param fragCharSize the length (number of chars) of a fragment
   */
  public FieldFragList( int fragCharSize ){
  }

  /**
   * convert the list of WeightedPhraseInfo to WeightedFragInfo, then add it to the fragInfos
   * 
   * @param startOffset start offset of the fragment
   * @param endOffset end offset of the fragment
   * @param phraseInfoList list of WeightedPhraseInfo objects
   */
  public void add( int startOffset, int endOffset, List<WeightedPhraseInfo> phraseInfoList ){
    fragInfos.add( new WeightedFragInfo( startOffset, endOffset, phraseInfoList ) );
  }
  
  /**
   * return the list of WeightedFragInfos.
   * 
   * @return fragInfos.
   */ 
  public List<WeightedFragInfo> getFragInfos() {
    return fragInfos;
  }

  public static class WeightedFragInfo {

    List<SubInfo> subInfos;
    float totalBoost;
    int startOffset;
    int endOffset;

    public WeightedFragInfo( int startOffset, int endOffset, List<WeightedPhraseInfo> phraseInfoList ){
      this.startOffset = startOffset;
      this.endOffset = endOffset;
      subInfos = new ArrayList<SubInfo>();
      for( WeightedPhraseInfo phraseInfo : phraseInfoList ){
        SubInfo subInfo = new SubInfo( phraseInfo.text, phraseInfo.termsOffsets, phraseInfo.seqnum );
        subInfos.add( subInfo );
        totalBoost += phraseInfo.boost;
      }
    }
    
    public List<SubInfo> getSubInfos(){
      return subInfos;
    }
    
    public float getTotalBoost(){
      return totalBoost;
    }
    
    public int getStartOffset(){
      return startOffset;
    }
    
    public int getEndOffset(){
      return endOffset;
    }
    
    @Override
    public String toString(){
      StringBuilder sb = new StringBuilder();
      sb.append( "subInfos=(" );
      for( SubInfo si : subInfos )
        sb.append( si.toString() );
      sb.append( ")/" ).append( totalBoost ).append( '(' ).append( startOffset ).append( ',' ).append( endOffset ).append( ')' );
      return sb.toString();
    }
    
    public static class SubInfo {
      final String text;  // unnecessary member, just exists for debugging purpose
      final List<Toffs> termsOffsets;   // usually termsOffsets.size() == 1,
                              // but if position-gap > 1 and slop > 0 then size() could be greater than 1
      int seqnum;

      SubInfo( String text, List<Toffs> termsOffsets, int seqnum ){
        this.text = text;
        this.termsOffsets = termsOffsets;
        this.seqnum = seqnum;
      }
      
      public List<Toffs> getTermsOffsets(){
        return termsOffsets;
      }
      
      public int getSeqnum(){
        return seqnum;
      }
      
      @Override
      public String toString(){
        StringBuilder sb = new StringBuilder();
        sb.append( text ).append( '(' );
        for( Toffs to : termsOffsets )
          sb.append( to.toString() );
        sb.append( ')' );
        return sb.toString();
      }
    }
  }
}