content: package org.apache.lucene.index;
  /**
   * Copyright 2007 The Apache Software Foundation
   *
   * Licensed 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.
   */
  
  
  /**
   * The TermVectorMapper can be used to map Term Vectors into your own
   * structure instead of the parallel array structure used by
   * {@link org.apache.lucene.index.IndexReader#getTermFreqVector(int,String)}.
   * <p/>
   * It is up to the implementation to make sure it is thread-safe.
   *
   *
   **/
  public abstract class TermVectorMapper {
  
    private boolean ignoringPositions;
    private boolean ignoringOffsets;
  
  
    protected TermVectorMapper() {
    }
  
    /**
     *
     * @param ignoringPositions true if this mapper should tell Lucene to ignore positions even if they are stored
     * @param ignoringOffsets similar to ignoringPositions
     */
    protected TermVectorMapper(boolean ignoringPositions, boolean ignoringOffsets) {
      this.ignoringPositions = ignoringPositions;
      this.ignoringOffsets = ignoringOffsets;
    }
  
    /**
     * Tell the mapper what to expect in regards to field, number of terms, offset and position storage.
     * This method will be called once before retrieving the vector for a field.
     *
     * This method will be called before {@link #map(String,int,TermVectorOffsetInfo[],int[])}.
     * @param field The field the vector is for
     * @param numTerms The number of terms that need to be mapped
     * @param storeOffsets true if the mapper should expect offset information
     * @param storePositions true if the mapper should expect positions info
     */
    public abstract void setExpectations(String field, int numTerms, boolean storeOffsets, boolean storePositions);
    /**
     * Map the Term Vector information into your own structure
     * @param term The term to add to the vector
     * @param frequency The frequency of the term in the document
     * @param offsets null if the offset is not specified, otherwise the offset into the field of the term
     * @param positions null if the position is not specified, otherwise the position in the field of the term
     */
    public abstract void map(String term, int frequency, TermVectorOffsetInfo [] offsets, int [] positions);
  
    /**
     * Indicate to Lucene that even if there are positions stored, this mapper is not interested in them and they
     * can be skipped over.  Derived classes should set this to true if they want to ignore positions.  The default
     * is false, meaning positions will be loaded if they are stored.
     * @return false
     */
    public boolean isIgnoringPositions()
    {
      return ignoringPositions;
    }
  
    /**
     *
     * @see #isIgnoringPositions() Same principal as {@link #isIgnoringPositions()}, but applied to offsets.  false by default.
     * @return false
     */
    public boolean isIgnoringOffsets()
    {
      return ignoringOffsets;
    }
  
    /**
     * Passes down the index of the document whose term vector is currently being mapped,
     * once for each top level call to a term vector reader.
     *<p/>
     * Default implementation IGNORES the document number.  Override if your implementation needs the document number.
     * <p/> 
     * NOTE: Document numbers are internal to Lucene and subject to change depending on indexing operations.
     *
     * @param documentNumber index of document currently being mapped
     */
    public void setDocumentNumber(int documentNumber) {
    }
  
  }
  