How to use

emptySortedSet

method

in

org.apache.lucene.index.DocValues

@Override
public SortedSetDocValues getSortedSetDocValues( String field )
{
  return DocValues.emptySortedSet();
}

/**
 * Returns SortedSetDocValues for the field, or {@link #emptySortedSet} if it has none. 
 * @return docvalues instance, or an empty instance if {@code field} does not exist in this reader.
 * @throws IllegalStateException if {@code field} exists, but was not indexed with docvalues.
 * @throws IllegalStateException if {@code field} has docvalues, but the type is not {@link DocValuesType#SORTED_SET}
 *                               or {@link DocValuesType#SORTED}.
 * @throws IOException if an I/O error occurs.
 */
public static SortedSetDocValues getSortedSet(LeafReader reader, String field) throws IOException {
 SortedSetDocValues dv = reader.getSortedSetDocValues(field);
 if (dv == null) {
  SortedDocValues sorted = reader.getSortedDocValues(field);
  if (sorted == null) {
   checkField(reader, field, DocValuesType.SORTED, DocValuesType.SORTED_SET);
   return emptySortedSet();
  }
  dv = singleton(sorted);
 }
 return dv;
}

values = DocValues.emptySortedSet();

SortedSetDocValues v = context.reader().getSortedSetDocValues(field);
if (v == null) {
 v = DocValues.emptySortedSet();
} else {
 anyReal = true;

  @Override
  public SortedSetDocValues getOrdinalsValues() {
    return DocValues.emptySortedSet();
  }
};

@Override
public SortedSetDocValues globalOrdinalsValues(LeafReaderContext context) {
  return DocValues.emptySortedSet();
}

@Override
public SortedSetDocValues ordinalsValues(LeafReaderContext context) {
  return DocValues.emptySortedSet();
}

@Override
public SortedSetDocValues getOrdinalsValues() {
  return DocValues.emptySortedSet();
}

values = DocValues.emptySortedSet();

return select(DocValues.emptySortedSet());

public GlobalOrdinalsStringTermsAggregator(String name, AggregatorFactories factories,
                      ValuesSource.Bytes.WithOrdinals valuesSource,
                      BucketOrder order,
                      DocValueFormat format,
                      BucketCountThresholds bucketCountThresholds,
                      IncludeExclude.OrdinalsFilter includeExclude,
                      SearchContext context,
                      Aggregator parent,
                      boolean remapGlobalOrds,
                      SubAggCollectionMode collectionMode,
                      boolean showTermDocCountError,
                      List<PipelineAggregator> pipelineAggregators,
                      Map<String, Object> metaData) throws IOException {
  super(name, factories, context, parent, order, format, bucketCountThresholds, collectionMode, showTermDocCountError,
    pipelineAggregators, metaData);
  this.valuesSource = valuesSource;
  this.includeExclude = includeExclude;
  final IndexReader reader = context.searcher().getIndexReader();
  final SortedSetDocValues values = reader.leaves().size() > 0 ?
    valuesSource.globalOrdinalsValues(context.searcher().getIndexReader().leaves().get(0)) : DocValues.emptySortedSet();
  this.valueCount = values.getValueCount();
  this.lookupGlobalOrd = values::lookupOrd;
  this.acceptedGlobalOrdinals = includeExclude != null ? includeExclude.acceptedGlobalOrdinals(values) : null;
  this.bucketOrds = remapGlobalOrds ? new LongHash(1, context.bigArrays()) : null;
}

v = DocValues.emptySortedSet();

  @Override
  public RandomAccessOrds getOrdinalsValues() {
    return DocValues.emptySortedSet();
  }
};

  @Override
  public SortedSetDocValues getOrdinalsValues() {
    return DocValues.emptySortedSet();
  }
};

  @Override
  public SortedSetDocValues getOrdinalsValues() {
    return DocValues.emptySortedSet();
  }
};

  @Override
  public RandomAccessOrds getOrdinalsValues() {
    return DocValues.emptySortedSet();
  }
};

@Override
public RandomAccessOrds getOrdinalsValues() {
  return DocValues.emptySortedSet();
}

@Override
public RandomAccessOrds globalOrdinalsValues(LeafReaderContext context) {
  return DocValues.emptySortedSet();
}

/** Returns a SortedSetDocValues view of this instance */
public SortedSetDocValues iterator(LeafReader reader) throws IOException {
 if (isEmpty()) {
  return DocValues.emptySortedSet();
 } else {
  return new Iterator(reader);
 }
}

/** Returns a SortedSetDocValues view of this instance */
public SortedSetDocValues iterator(LeafReader reader) throws IOException {
 if (isEmpty()) {
  return DocValues.emptySortedSet();
 } else {
  return new Iterator(reader);
 }
}