content: package org.apache.lucene.analysis.tokenattributes;
  
  /**
   * 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.Serializable;
  
  import org.apache.lucene.analysis.TokenStream;
  import org.apache.lucene.util.AttributeImpl;
  
  /** The positionIncrement determines the position of this token
   * relative to the previous Token in a {@link TokenStream}, used in phrase
   * searching.
   *
   * <p>The default value is one.
   *
   * <p>Some common uses for this are:<ul>
   *
   * <li>Set it to zero to put multiple terms in the same position.  This is
   * useful if, e.g., a word has multiple stems.  Searches for phrases
   * including either stem will match.  In this case, all but the first stem's
   * increment should be set to zero: the increment of the first instance
   * should be one.  Repeating a token with an increment of zero can also be
   * used to boost the scores of matches on that token.
   *
   * <li>Set it to values greater than one to inhibit exact phrase matches.
   * If, for example, one does not want phrases to match across removed stop
   * words, then one could build a stop word filter that removes stop words and
   * also sets the increment to the number of stop words removed before each
   * non-stop word.  Then exact phrase queries will only match when the terms
   * occur with no intervening stop words.
   *
   * </ul>
   */
  public class PositionIncrementAttributeImpl extends AttributeImpl implements PositionIncrementAttribute, Cloneable, Serializable {
    private int positionIncrement = 1;
    
    /** Set the position increment. The default value is one.
     *
     * @param positionIncrement the distance from the prior term
     */
    public void setPositionIncrement(int positionIncrement) {
      if (positionIncrement < 0)
        throw new IllegalArgumentException
          ("Increment must be zero or greater: " + positionIncrement);
      this.positionIncrement = positionIncrement;
    }
  
    /** Returns the position increment of this Token.
     * @see #setPositionIncrement
     */
    public int getPositionIncrement() {
      return positionIncrement;
    }
  
    @Override
    public void clear() {
      this.positionIncrement = 1;
    }
    
    @Override
    public boolean equals(Object other) {
      if (other == this) {
        return true;
      }
      
      if (other instanceof PositionIncrementAttributeImpl) {
        return positionIncrement == ((PositionIncrementAttributeImpl) other).positionIncrement;
      }
   
      return false;
    }
  
    @Override
    public int hashCode() {
      return positionIncrement;
    }
    
    @Override
    public void copyTo(AttributeImpl target) {
      PositionIncrementAttribute t = (PositionIncrementAttribute) target;
      t.setPositionIncrement(positionIncrement);
    }  
  
  }
  