How to use

emptyBinary

method

in

org.apache.lucene.index.DocValues

@Override
public BinaryDocValues getBinaryDocValues( String field )
{
  return DocValues.emptyBinary();
}

/**
 * Returns BinaryDocValues for the field, or {@link #emptyBinary} 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#BINARY}
 *                               or {@link DocValuesType#SORTED}.
 * @throws IOException if an I/O error occurs.
 */
public static BinaryDocValues getBinary(LeafReader reader, String field) throws IOException {
 BinaryDocValues dv = reader.getBinaryDocValues(field);
 if (dv == null) {
  dv = reader.getSortedDocValues(field);
  if (dv == null) {
   checkField(reader, field, DocValuesType.BINARY, DocValuesType.SORTED);
   return emptyBinary();
  }
 }
 return dv;
}

BinaryEntry entry = binaries.get(field.name);
if (entry.docsWithFieldOffset == -2) {
 return DocValues.emptyBinary();

/**
 * Return a {@link SortedBinaryDocValues} that doesn't contain any value.
 */
public static SortedBinaryDocValues emptySortedBinary() {
  return singleton(DocValues.emptyBinary());
}

/**
 * Return a {@link SortedBinaryDocValues} that doesn't contain any value.
 */
public static SortedBinaryDocValues emptySortedBinary() {
  return singleton(DocValues.emptyBinary());
}

/**
 * Return a {@link SortedBinaryDocValues} that doesn't contain any value.
 */
public static SortedBinaryDocValues emptySortedBinary() {
  return singleton(DocValues.emptyBinary());
}

/**
 * Return a {@link SortedBinaryDocValues} that doesn't contain any value.
 */
public static SortedBinaryDocValues emptySortedBinary(int maxDoc) {
  return singleton(DocValues.emptyBinary(), new Bits.MatchNoBits(maxDoc));
}

/**
 * Return a {SortedBinaryDocValues} that doesn't contain any value.
 */
public static SortedBinaryDocValues emptySortedBinary(int maxDoc) {
  return singleton(DocValues.emptyBinary(), new Bits.MatchNoBits(maxDoc));
}

/**
 * Return a {@link SortedBinaryDocValues} that doesn't contain any value.
 */
public static SortedBinaryDocValues emptySortedBinary(int maxDoc) {
  return singleton(DocValues.emptyBinary(), new Bits.MatchNoBits(maxDoc));
}

@Override
public OrdinalsSegmentReader getReader(LeafReaderContext context) throws IOException {
 BinaryDocValues values0 = context.reader().getBinaryDocValues(field);
 if (values0 == null) {
  values0 = DocValues.emptyBinary();
 }
 final BinaryDocValues values = values0;
 return new OrdinalsSegmentReader() {
  @Override
  public void get(int docID, IntsRef ordinals) throws IOException {
   final BytesRef bytes = values.get(docID);
   decode(bytes, ordinals);
  }
 };
}

@Override
public OrdinalsSegmentReader getReader(LeafReaderContext context) throws IOException {
 BinaryDocValues values0 = context.reader().getBinaryDocValues(field);
 if (values0 == null) {
  values0 = DocValues.emptyBinary();
 }
 final BinaryDocValues values = values0;
 return new OrdinalsSegmentReader() {
  private int lastDocID;
  
  @Override
  public void get(int docID, IntsRef ordinals) throws IOException {
   if (docID < lastDocID) {
    throw new AssertionError("docs out of order: lastDocID=" + lastDocID + " vs docID=" + docID);
   }
   lastDocID = docID;
   if (docID > values.docID()) {
    values.advance(docID);
   }
   final BytesRef bytes;
   if (values.docID() == docID) {
    bytes = values.binaryValue();
   } else {
    bytes = new BytesRef(BytesRef.EMPTY_BYTES);
   }
   decode(bytes, ordinals);
  }
 };
}

/**
 * Returns BinaryDocValues for the field, or {@link #emptyBinary} 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#BINARY}
 *                               or {@link DocValuesType#SORTED}.
 * @throws IOException if an I/O error occurs.
 */
public static BinaryDocValues getBinary(LeafReader reader, String field) throws IOException {
 BinaryDocValues dv = reader.getBinaryDocValues(field);
 if (dv == null) {
  dv = reader.getSortedDocValues(field);
  if (dv == null) {
   checkField(reader, field, DocValuesType.BINARY, DocValuesType.SORTED);
   return emptyBinary();
  }
 }
 return dv;
}

/**
 * Returns BinaryDocValues for the field, or {@link #emptyBinary} 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#BINARY}
 *                               or {@link DocValuesType#SORTED}.
 * @throws IOException if an I/O error occurs.
 */
public static BinaryDocValues getBinary(LeafReader reader, String field) throws IOException {
 BinaryDocValues dv = reader.getBinaryDocValues(field);
 if (dv == null) {
  dv = reader.getSortedDocValues(field);
  if (dv == null) {
   checkField(reader, field, DocValuesType.BINARY, DocValuesType.SORTED);
   return emptyBinary();
  }
 }
 return dv;
}

/**
 * Returns BinaryDocValues for the field, or {@link #emptyBinary} 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#BINARY}
 *                               or {@link DocValuesType#SORTED}.
 * @throws IOException if an I/O error occurs.
 */
public static BinaryDocValues getBinary(LeafReader reader, String field) throws IOException {
 BinaryDocValues dv = reader.getBinaryDocValues(field);
 if (dv == null) {
  dv = reader.getSortedDocValues(field);
  if (dv == null) {
   checkField(reader, field, DocValuesType.BINARY, DocValuesType.SORTED);
   return emptyBinary();
  }
 }
 return dv;
}

public BinaryDocValues getTerms(LeafReader reader, String field, boolean setDocsWithField, float acceptableOverheadRatio) throws IOException {
 BinaryDocValues valuesIn = reader.getBinaryDocValues(field);
 if (valuesIn == null) {
  valuesIn = reader.getSortedDocValues(field);
 }
 if (valuesIn != null) {
  // Not cached here by FieldCacheImpl (cached instead
  // per-thread by SegmentReader):
  return valuesIn;
 }
 final FieldInfo info = reader.getFieldInfos().fieldInfo(field);
 if (info == null) {
  return DocValues.emptyBinary();
 } else if (info.getDocValuesType() != DocValuesType.NONE) {
  throw new IllegalStateException("Type mismatch: " + field + " was indexed as " + info.getDocValuesType());
 } else if (info.getIndexOptions() == IndexOptions.NONE) {
  return DocValues.emptyBinary();
 }
 BinaryDocValuesImpl impl = (BinaryDocValuesImpl) caches.get(BinaryDocValues.class).get(reader, new CacheKey(field, acceptableOverheadRatio), setDocsWithField);
 return impl.iterator();
}

public BinaryDocValues getTerms(LeafReader reader, String field, boolean setDocsWithField, float acceptableOverheadRatio) throws IOException {
 BinaryDocValues valuesIn = reader.getBinaryDocValues(field);
 if (valuesIn == null) {
  valuesIn = reader.getSortedDocValues(field);
 }
 if (valuesIn != null) {
  // Not cached here by FieldCacheImpl (cached instead
  // per-thread by SegmentReader):
  return valuesIn;
 }
 final FieldInfo info = reader.getFieldInfos().fieldInfo(field);
 if (info == null) {
  return DocValues.emptyBinary();
 } else if (info.getDocValuesType() != DocValuesType.NONE) {
  throw new IllegalStateException("Type mismatch: " + field + " was indexed as " + info.getDocValuesType());
 } else if (info.getIndexOptions() == IndexOptions.NONE) {
  return DocValues.emptyBinary();
 }
 BinaryDocValuesImpl impl = (BinaryDocValuesImpl) caches.get(BinaryDocValues.class).get(reader, new CacheKey(field, acceptableOverheadRatio), setDocsWithField);
 return impl.iterator();
}

BinaryDocValues v = context.reader().getBinaryDocValues(field);
if (v == null) {
 v = DocValues.emptyBinary();
} else {
 anyReal = true;

BinaryDocValues v = context.reader().getBinaryDocValues(field);
if (v == null) {
 v = DocValues.emptyBinary();
} else {
 anyReal = true;

values = DocValues.emptyBinary();
bits = new Bits.MatchNoBits(mergeState.maxDocs[i]);

BinaryEntry entry = binaries.get(field.name);
if (entry.docsWithFieldOffset == -2) {
 return DocValues.emptyBinary();