code: public Indexer getIndexer(Field field) {
      PropertyIndexer indexerAnnotation = field.getAnnotation(PropertyIndexer.class);
      if (indexerAnnotation != null) {
        Class<? extends Indexer> indexerClass = indexerAnnotation.value();
        return getIndexer(indexerClass);
      }
      return getDefaultIndexer(field);
    }
docs: Gets the {@link Indexer} for the given field. If the field has a {@link PropertyIndexer}
  annotation, the specified indexer will be returned. Otherwise, a default indexer will be
  returned based on the field's type.
  
  @param field
  the field
  @return the indexer for the specified field.