content: package org.apache.lucene.search.highlight;
  
  
  /**
   * 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.List;
  
  import org.apache.lucene.analysis.TokenStream;
  import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
  import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
  import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
  import org.apache.lucene.search.spans.Spans;
  
  
  /**
   * {@link Fragmenter} implementation which breaks text up into same-size
   * fragments but does not split up {@link Spans}. This is a simple sample class.
   */
  public class SimpleSpanFragmenter implements Fragmenter {
    private static final int DEFAULT_FRAGMENT_SIZE = 100;
    private int fragmentSize;
    private int currentNumFrags;
    private int position = -1;
    private QueryScorer queryScorer;
    private int waitForPos = -1;
    private int textSize;
    private CharTermAttribute termAtt;
    private PositionIncrementAttribute posIncAtt;
    private OffsetAttribute offsetAtt;
  
    /**
     * @param queryScorer QueryScorer that was used to score hits
     */
    public SimpleSpanFragmenter(QueryScorer queryScorer) {
      this(queryScorer, DEFAULT_FRAGMENT_SIZE);
    }
  
    /**
     * @param queryScorer QueryScorer that was used to score hits
     * @param fragmentSize size in bytes of each fragment
     */
    public SimpleSpanFragmenter(QueryScorer queryScorer, int fragmentSize) {
      this.fragmentSize = fragmentSize;
      this.queryScorer = queryScorer;
    }
    
    /* (non-Javadoc)
     * @see org.apache.lucene.search.highlight.Fragmenter#isNewFragment()
     */
    public boolean isNewFragment() {
      position += posIncAtt.getPositionIncrement();
  
      if (waitForPos == position) {
        waitForPos = -1;
      } else if (waitForPos != -1) {
        return false;
      }
  
      WeightedSpanTerm wSpanTerm = queryScorer.getWeightedSpanTerm(termAtt.toString());
  
      if (wSpanTerm != null) {
        List<PositionSpan> positionSpans = wSpanTerm.getPositionSpans();
  
        for (int i = 0; i < positionSpans.size(); i++) {
          if (positionSpans.get(i).start == position) {
            waitForPos = positionSpans.get(i).end + 1;
            break;
          }
        }
      }
  
      boolean isNewFrag = offsetAtt.endOffset() >= (fragmentSize * currentNumFrags)
          && (textSize - offsetAtt.endOffset()) >= (fragmentSize >>> 1);
      
      if (isNewFrag) {
        currentNumFrags++;
      }
  
      return isNewFrag;
    }
  
  
    /* (non-Javadoc)
     * @see org.apache.lucene.search.highlight.Fragmenter#start(java.lang.String, org.apache.lucene.analysis.TokenStream)
     */
    public void start(String originalText, TokenStream tokenStream) {
      position = -1;
      currentNumFrags = 1;
      textSize = originalText.length();
      termAtt = tokenStream.addAttribute(CharTermAttribute.class);
      posIncAtt = tokenStream.addAttribute(PositionIncrementAttribute.class);
      offsetAtt = tokenStream.addAttribute(OffsetAttribute.class);
    }
  }
  