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.io.IOException;
  import java.util.ArrayList;
  import java.util.Comparator;
  import java.util.Iterator;
  import java.util.List;
  
  import org.apache.lucene.analysis.Token;
  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.index.TermPositionVector;
  import org.apache.lucene.index.TermVectorOffsetInfo;
  import org.apache.lucene.util.CollectionUtil;
  
  public final class TokenStreamFromTermPositionVector extends TokenStream {
  
    private final List<Token> positionedTokens = new ArrayList<Token>();
  
    private Iterator<Token> tokensAtCurrentPosition;
  
    private CharTermAttribute termAttribute;
  
    private PositionIncrementAttribute positionIncrementAttribute;
  
    private OffsetAttribute offsetAttribute;
  
    /**
     * Constructor.
     * 
     * @param termPositionVector TermPositionVector that contains the data for
     *        creating the TokenStream. Must have positions and offsets.
     */
    public TokenStreamFromTermPositionVector(
        final TermPositionVector termPositionVector) {
      termAttribute = addAttribute(CharTermAttribute.class);
      positionIncrementAttribute = addAttribute(PositionIncrementAttribute.class);
      offsetAttribute = addAttribute(OffsetAttribute.class);
      final String[] terms = termPositionVector.getTerms();
      for (int i = 0; i < terms.length; i++) {
        final TermVectorOffsetInfo[] offsets = termPositionVector.getOffsets(i);
        final int[] termPositions = termPositionVector.getTermPositions(i);
        for (int j = 0; j < termPositions.length; j++) {
          Token token;
          if (offsets != null) {
            token = new Token(terms[i].toCharArray(), 0, terms[i].length(),
                offsets[j].getStartOffset(), offsets[j].getEndOffset());
          } else {
            token = new Token();
            token.setEmpty().append(terms[i]);
          }
          // Yes - this is the position, not the increment! This is for
          // sorting. This value
          // will be corrected before use.
          token.setPositionIncrement(termPositions[j]);
          this.positionedTokens.add(token);
        }
      }
      CollectionUtil.mergeSort(this.positionedTokens, tokenComparator);
      int lastPosition = -1;
      for (final Token token : this.positionedTokens) {
        int thisPosition = token.getPositionIncrement();
        token.setPositionIncrement(thisPosition - lastPosition);
        lastPosition = thisPosition;
      }
      this.tokensAtCurrentPosition = this.positionedTokens.iterator();
    }
  
    private static final Comparator<Token> tokenComparator = new Comparator<Token>() {
      public int compare(final Token o1, final Token o2) {
        return o1.getPositionIncrement() - o2.getPositionIncrement();
      }
    };
    
    @Override
    public boolean incrementToken() throws IOException {
      if (this.tokensAtCurrentPosition.hasNext()) {
        final Token next = this.tokensAtCurrentPosition.next();
        clearAttributes();
        termAttribute.setEmpty().append(next);
        positionIncrementAttribute.setPositionIncrement(next
            .getPositionIncrement());
        offsetAttribute.setOffset(next.startOffset(), next.endOffset());
        return true;
      }
      return false;
    }
  
    @Override
    public void reset() throws IOException {
      this.tokensAtCurrentPosition = this.positionedTokens.iterator();
    }
  }
  