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.
   */
  
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  /**
   * For each Field, store position by position information.  It ignores frequency information
   * <p/>
   * This is not thread-safe.
   */
  public class PositionBasedTermVectorMapper extends TermVectorMapper{
    private Map<String, Map<Integer,TVPositionInfo>> fieldToTerms;
  
    private String currentField;
    /**
     * A Map of Integer and TVPositionInfo
     */
    private Map<Integer,TVPositionInfo> currentPositions;
    private boolean storeOffsets;
  
    
  
  
    /**
     *
     *
     */
    public PositionBasedTermVectorMapper() {
      super(false, false);
    }
  
    public PositionBasedTermVectorMapper(boolean ignoringOffsets)
    {
      super(false, ignoringOffsets);
    }
  
    /**
     * Never ignores positions.  This mapper doesn't make much sense unless there are positions
     * @return false
     */
    @Override
    public boolean isIgnoringPositions() {
      return false;
    }
  
    /**
     * Callback for the TermVectorReader. 
     * @param term
     * @param frequency
     * @param offsets
     * @param positions
     */
    @Override
    public void map(String term, int frequency, TermVectorOffsetInfo[] offsets, int[] positions) {
      for (int i = 0; i < positions.length; i++) {
        Integer posVal = Integer.valueOf(positions[i]);
        TVPositionInfo pos = currentPositions.get(posVal);
        if (pos == null) {
          pos = new TVPositionInfo(positions[i], storeOffsets);
          currentPositions.put(posVal, pos);
        }
        pos.addTerm(term, offsets != null ? offsets[i] : null);
      }
    }
  
    /**
     * Callback mechanism used by the TermVectorReader
     * @param field  The field being read
     * @param numTerms The number of terms in the vector
     * @param storeOffsets Whether offsets are available
     * @param storePositions Whether positions are available
     */
    @Override
    public void setExpectations(String field, int numTerms, boolean storeOffsets, boolean storePositions) {
      if (storePositions == false)
      {
        throw new RuntimeException("You must store positions in order to use this Mapper");
      }
      if (storeOffsets == true)
      {
        //ignoring offsets
      }
      fieldToTerms = new HashMap<String,Map<Integer,TVPositionInfo>>(numTerms);
      this.storeOffsets = storeOffsets;
      currentField = field;
      currentPositions = new HashMap<Integer,TVPositionInfo>();
      fieldToTerms.put(currentField, currentPositions);
    }
  
    /**
     * Get the mapping between fields and terms, sorted by the comparator
     *
     * @return A map between field names and a Map.  The sub-Map key is the position as the integer, the value is {@link org.apache.lucene.index.PositionBasedTermVectorMapper.TVPositionInfo}.
     */
    public Map<String,Map<Integer,TVPositionInfo>>  getFieldToTerms() {
      return fieldToTerms;
    }
  
    /**
     * Container for a term at a position
     */
    public static class TVPositionInfo{
      private int position;
  
      private List<String> terms;
  
      private List<TermVectorOffsetInfo> offsets;
  
  
      public TVPositionInfo(int position, boolean storeOffsets) {
        this.position = position;
        terms = new ArrayList<String>();
        if (storeOffsets) {
          offsets = new ArrayList<TermVectorOffsetInfo>();
        }
      }
  
      void addTerm(String term, TermVectorOffsetInfo info)
      {
        terms.add(term);
        if (offsets != null) {
          offsets.add(info);
        }
      }
  
      /**
       *
       * @return The position of the term
       */
      public int getPosition() {
        return position;
      }
  
      /**
       * Note, there may be multiple terms at the same position
       * @return A List of Strings
       */
      public List<String> getTerms() {
        return terms;
      }
  
      /**
       * Parallel list (to {@link #getTerms()}) of TermVectorOffsetInfo objects.  There may be multiple entries since there may be multiple terms at a position
       * @return A List of TermVectorOffsetInfo objects, if offsets are stored.
       */
      public List<TermVectorOffsetInfo> getOffsets() {
        return offsets;
      }
    }
  
  
  }
  