content: package org.apache.lucene.analysis.position;
  
  /**
   * 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 org.apache.lucene.analysis.TokenFilter;
  import org.apache.lucene.analysis.TokenStream;
  import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
  
  /** Set the positionIncrement of all tokens to the "positionIncrement",
   * except the first return token which retains its original positionIncrement value.
   * The default positionIncrement value is zero.
   */
  public final class PositionFilter extends TokenFilter {
  
    /** Position increment to assign to all but the first token - default = 0 */
    private int positionIncrement = 0;
    
    /** The first token must have non-zero positionIncrement **/
    private boolean firstTokenPositioned = false;
    
    private PositionIncrementAttribute posIncrAtt = addAttribute(PositionIncrementAttribute.class);
  
    /**
     * Constructs a PositionFilter that assigns a position increment of zero to
     * all but the first token from the given input stream.
     * 
     * @param input the input stream
     */
    public PositionFilter(final TokenStream input) {
      super(input);
    }
  
    /**
     * Constructs a PositionFilter that assigns the given position increment to
     * all but the first token from the given input stream.
     * 
     * @param input the input stream
     * @param positionIncrement position increment to assign to all but the first
     *  token from the input stream
     */
    public PositionFilter(final TokenStream input, final int positionIncrement) {
      this(input);
      this.positionIncrement = positionIncrement;
    }
  
    @Override
    public final boolean incrementToken() throws IOException {
      if (input.incrementToken()) {
        if (firstTokenPositioned) {
          posIncrAtt.setPositionIncrement(positionIncrement);
        } else {
          firstTokenPositioned = true;
        }
        return true;
      } else {
        return false;
      }
    }
  
    @Override
    public void reset() throws IOException {
      super.reset();
      firstTokenPositioned = false;
    }
  }
  