package org.apache.lucene.codecs.memory;
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.io.IOException;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.atomic.AtomicLong;
import org.apache.lucene.codecs.CodecUtil;
import org.apache.lucene.codecs.DocValuesProducer;
import org.apache.lucene.index.BinaryDocValues;
import org.apache.lucene.index.CorruptIndexException;
import org.apache.lucene.index.DocValues;
import org.apache.lucene.index.DocsAndPositionsEnum;
import org.apache.lucene.index.DocsEnum;
import org.apache.lucene.index.FieldInfo;
import org.apache.lucene.index.FieldInfos;
import org.apache.lucene.index.IndexFileNames;
import org.apache.lucene.index.NumericDocValues;
import org.apache.lucene.index.SegmentReadState;
import org.apache.lucene.index.SortedDocValues;
import org.apache.lucene.index.SortedNumericDocValues;
import org.apache.lucene.index.SortedSetDocValues;
import org.apache.lucene.index.TermsEnum;
import org.apache.lucene.store.ByteArrayDataInput;
import org.apache.lucene.store.ChecksumIndexInput;
import org.apache.lucene.store.IndexInput;
import org.apache.lucene.util.Bits;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.FixedBitSet;
import org.apache.lucene.util.IOUtils;
import org.apache.lucene.util.IntsRef;
import org.apache.lucene.util.LongValues;
import org.apache.lucene.util.PagedBytes;
import org.apache.lucene.util.RamUsageEstimator;
import org.apache.lucene.util.fst.BytesRefFSTEnum;
import org.apache.lucene.util.fst.BytesRefFSTEnum.InputOutput;
import org.apache.lucene.util.fst.FST;
import org.apache.lucene.util.fst.FST.Arc;
import org.apache.lucene.util.fst.FST.BytesReader;
import org.apache.lucene.util.fst.PositiveIntOutputs;
import org.apache.lucene.util.fst.Util;
import org.apache.lucene.util.packed.BlockPackedReader;
import org.apache.lucene.util.packed.MonotonicBlockPackedReader;
import org.apache.lucene.util.packed.PackedInts;
/**
* Reader for {@link MemoryDocValuesFormat}
*/
class MemoryDocValuesProducer extends DocValuesProducer {
// metadata maps (just file pointers and minimal stuff)
private final Map<Integer,NumericEntry> numerics = new HashMap<>();
private final Map<Integer,BinaryEntry> binaries = new HashMap<>();
private final Map<Integer,FSTEntry> fsts = new HashMap<>();
private final Map<Integer,SortedSetEntry> sortedSets = new HashMap<>();
private final Map<Integer,SortedNumericEntry> sortedNumerics = new HashMap<>();
private final IndexInput data;
// ram instances we have already loaded
private final Map<Integer,NumericDocValues> numericInstances =
new HashMap<>();
private final Map<Integer,BytesAndAddresses> pagedBytesInstances =
new HashMap<>();
private final Map<Integer,FST<Long>> fstInstances =
new HashMap<>();
private final Map<Integer,Bits> docsWithFieldInstances = new HashMap<>();
private final Map<Integer,MonotonicBlockPackedReader> addresses = new HashMap<>();
private final int maxDoc;
private final AtomicLong ramBytesUsed;
private final int version;
static final byte NUMBER = 0;
static final byte BYTES = 1;
static final byte FST = 2;
static final byte SORTED_SET = 4;
static final byte SORTED_SET_SINGLETON = 5;
static final byte SORTED_NUMERIC = 6;
static final byte SORTED_NUMERIC_SINGLETON = 7;
static final int BLOCK_SIZE = 4096;
static final byte DELTA_COMPRESSED = 0;
static final byte TABLE_COMPRESSED = 1;
static final byte BLOCK_COMPRESSED = 2;
static final byte GCD_COMPRESSED = 3;
static final int VERSION_START = 3;
static final int VERSION_CURRENT = VERSION_START;
MemoryDocValuesProducer(SegmentReadState state, String dataCodec, String dataExtension, String metaCodec, String metaExtension) throws IOException {
maxDoc = state.segmentInfo.getDocCount();
String metaName = IndexFileNames.segmentFileName(state.segmentInfo.name, state.segmentSuffix, metaExtension);
// read in the entries from the metadata file.
ChecksumIndexInput in = state.directory.openChecksumInput(metaName, state.context);
boolean success = false;
try {
version = CodecUtil.checkHeader(in, metaCodec,
VERSION_START,
VERSION_CURRENT);
readFields(in, state.fieldInfos);
CodecUtil.checkFooter(in);
ramBytesUsed = new AtomicLong(RamUsageEstimator.shallowSizeOfInstance(getClass()));
success = true;
} finally {
if (success) {
IOUtils.close(in);
} else {
IOUtils.closeWhileHandlingException(in);
}
}
String dataName = IndexFileNames.segmentFileName(state.segmentInfo.name, state.segmentSuffix, dataExtension);
this.data = state.directory.openInput(dataName, state.context);
success = false;
try {
final int version2 = CodecUtil.checkHeader(data, dataCodec,
VERSION_START,
VERSION_CURRENT);
if (version != version2) {
throw new CorruptIndexException("Format versions mismatch");
}
success = true;
} finally {
if (!success) {
IOUtils.closeWhileHandlingException(this.data);
}
}
}
private NumericEntry readNumericEntry(IndexInput meta) throws IOException {
NumericEntry entry = new NumericEntry();
entry.offset = meta.readLong();
entry.missingOffset = meta.readLong();
if (entry.missingOffset != -1) {
entry.missingBytes = meta.readLong();
} else {
entry.missingBytes = 0;
}
entry.format = meta.readByte();
switch(entry.format) {
case DELTA_COMPRESSED:
case TABLE_COMPRESSED:
case BLOCK_COMPRESSED:
case GCD_COMPRESSED:
break;
default:
throw new CorruptIndexException("Unknown format: " + entry.format + ", input=" + meta);
}
entry.packedIntsVersion = meta.readVInt();
entry.count = meta.readLong();
return entry;
}
private BinaryEntry readBinaryEntry(IndexInput meta) throws IOException {
BinaryEntry entry = new BinaryEntry();
entry.offset = meta.readLong();
entry.numBytes = meta.readLong();
entry.missingOffset = meta.readLong();
if (entry.missingOffset != -1) {
entry.missingBytes = meta.readLong();
} else {
entry.missingBytes = 0;
}
entry.minLength = meta.readVInt();
entry.maxLength = meta.readVInt();
if (entry.minLength != entry.maxLength) {
entry.packedIntsVersion = meta.readVInt();
entry.blockSize = meta.readVInt();
}
return entry;
}
private FSTEntry readFSTEntry(IndexInput meta) throws IOException {
FSTEntry entry = new FSTEntry();
entry.offset = meta.readLong();
entry.numOrds = meta.readVLong();
return entry;
}
private void readFields(IndexInput meta, FieldInfos infos) throws IOException {
int fieldNumber = meta.readVInt();
while (fieldNumber != -1) {
int fieldType = meta.readByte();
if (fieldType == NUMBER) {
numerics.put(fieldNumber, readNumericEntry(meta));
} else if (fieldType == BYTES) {
binaries.put(fieldNumber, readBinaryEntry(meta));
} else if (fieldType == FST) {
fsts.put(fieldNumber,readFSTEntry(meta));
} else if (fieldType == SORTED_SET) {
SortedSetEntry entry = new SortedSetEntry();
entry.singleton = false;
sortedSets.put(fieldNumber, entry);
} else if (fieldType == SORTED_SET_SINGLETON) {
SortedSetEntry entry = new SortedSetEntry();
entry.singleton = true;
sortedSets.put(fieldNumber, entry);
} else if (fieldType == SORTED_NUMERIC) {
SortedNumericEntry entry = new SortedNumericEntry();
entry.singleton = false;
entry.packedIntsVersion = meta.readVInt();
entry.blockSize = meta.readVInt();
entry.addressOffset = meta.readLong();
entry.valueCount = meta.readLong();
sortedNumerics.put(fieldNumber, entry);
} else if (fieldType == SORTED_NUMERIC_SINGLETON) {
SortedNumericEntry entry = new SortedNumericEntry();
entry.singleton = true;
sortedNumerics.put(fieldNumber, entry);
} else {
throw new CorruptIndexException("invalid entry type: " + fieldType + ", input=" + meta);
}
fieldNumber = meta.readVInt();
}
}
@Override
public synchronized NumericDocValues getNumeric(FieldInfo field) throws IOException {
NumericDocValues instance = numericInstances.get(field.number);
if (instance == null) {
instance = loadNumeric(field);
numericInstances.put(field.number, instance);
}
return instance;
}
@Override
public long ramBytesUsed() {
return ramBytesUsed.get();
}
@Override
public void checkIntegrity() throws IOException {
CodecUtil.checksumEntireFile(data);
}
private NumericDocValues loadNumeric(FieldInfo field) throws IOException {
NumericEntry entry = numerics.get(field.number);
data.seek(entry.offset + entry.missingBytes);
switch (entry.format) {
case TABLE_COMPRESSED:
int size = data.readVInt();
if (size > 256) {
throw new CorruptIndexException("TABLE_COMPRESSED cannot have more than 256 distinct values, input=" + data);
}
final long decode[] = new long[size];
for (int i = 0; i < decode.length; i++) {
decode[i] = data.readLong();
}
final int formatID = data.readVInt();
final int bitsPerValue = data.readVInt();
final PackedInts.Reader ordsReader = PackedInts.getReaderNoHeader(data, PackedInts.Format.byId(formatID), entry.packedIntsVersion, (int)entry.count, bitsPerValue);
ramBytesUsed.addAndGet(RamUsageEstimator.sizeOf(decode) + ordsReader.ramBytesUsed());
return new NumericDocValues() {
@Override
public long get(int docID) {
return decode[(int)ordsReader.get(docID)];
}
};
case DELTA_COMPRESSED:
final long minDelta = data.readLong();
final int formatIDDelta = data.readVInt();
final int bitsPerValueDelta = data.readVInt();
final PackedInts.Reader deltaReader = PackedInts.getReaderNoHeader(data, PackedInts.Format.byId(formatIDDelta), entry.packedIntsVersion, (int)entry.count, bitsPerValueDelta);
ramBytesUsed.addAndGet(deltaReader.ramBytesUsed());
return new NumericDocValues() {
@Override
public long get(int docID) {
return minDelta + deltaReader.get(docID);
}
};
case BLOCK_COMPRESSED:
final int blockSize = data.readVInt();
final BlockPackedReader reader = new BlockPackedReader(data, entry.packedIntsVersion, blockSize, entry.count, false);
ramBytesUsed.addAndGet(reader.ramBytesUsed());
return reader;
case GCD_COMPRESSED:
final long min = data.readLong();
final long mult = data.readLong();
final int formatIDGCD = data.readVInt();
final int bitsPerValueGCD = data.readVInt();
final PackedInts.Reader quotientReader = PackedInts.getReaderNoHeader(data, PackedInts.Format.byId(formatIDGCD), entry.packedIntsVersion, (int)entry.count, bitsPerValueGCD);
ramBytesUsed.addAndGet(quotientReader.ramBytesUsed());
return new NumericDocValues() {
@Override
public long get(int docID) {
return min + mult * quotientReader.get(docID);
}
};
default:
throw new AssertionError();
}
}
@Override
public BinaryDocValues getBinary(FieldInfo field) throws IOException {
BinaryEntry entry = binaries.get(field.number);
BytesAndAddresses instance;
synchronized (this) {
instance = pagedBytesInstances.get(field.number);
if (instance == null) {
instance = loadBinary(field);
pagedBytesInstances.put(field.number, instance);
}
}
final PagedBytes.Reader bytesReader = instance.reader;
final MonotonicBlockPackedReader addresses = instance.addresses;
if (addresses == null) {
assert entry.minLength == entry.maxLength;
final int fixedLength = entry.minLength;
return new BinaryDocValues() {
final BytesRef term = new BytesRef();
@Override
public BytesRef get(int docID) {
bytesReader.fillSlice(term, fixedLength * (long)docID, fixedLength);
return term;
}
};
} else {
return new BinaryDocValues() {
final BytesRef term = new BytesRef();
@Override
public BytesRef get(int docID) {
long startAddress = docID == 0 ? 0 : addresses.get(docID-1);
long endAddress = addresses.get(docID);
bytesReader.fillSlice(term, startAddress, (int) (endAddress - startAddress));
return term;
}
};
}
}
private BytesAndAddresses loadBinary(FieldInfo field) throws IOException {
BytesAndAddresses bytesAndAddresses = new BytesAndAddresses();
BinaryEntry entry = binaries.get(field.number);
data.seek(entry.offset);
PagedBytes bytes = new PagedBytes(16);
bytes.copy(data, entry.numBytes);
bytesAndAddresses.reader = bytes.freeze(true);
ramBytesUsed.addAndGet(bytesAndAddresses.reader.ramBytesUsed());
if (entry.minLength != entry.maxLength) {
data.seek(data.getFilePointer() + entry.missingBytes);
bytesAndAddresses.addresses = MonotonicBlockPackedReader.of(data, entry.packedIntsVersion, entry.blockSize, maxDoc, false);
ramBytesUsed.addAndGet(bytesAndAddresses.addresses.ramBytesUsed());
}
return bytesAndAddresses;
}
@Override
public SortedDocValues getSorted(FieldInfo field) throws IOException {
final FSTEntry entry = fsts.get(field.number);
if (entry.numOrds == 0) {
return DocValues.emptySorted();
}
FST<Long> instance;
synchronized(this) {
instance = fstInstances.get(field.number);
if (instance == null) {
data.seek(entry.offset);
instance = new FST<>(data, PositiveIntOutputs.getSingleton());
ramBytesUsed.addAndGet(instance.ramBytesUsed());
fstInstances.put(field.number, instance);
}
}
final NumericDocValues docToOrd = getNumeric(field);
final FST<Long> fst = instance;
// per-thread resources
final BytesReader in = fst.getBytesReader();
final Arc<Long> firstArc = new Arc<>();
final Arc<Long> scratchArc = new Arc<>();
final IntsRef scratchInts = new IntsRef();
final BytesRefFSTEnum<Long> fstEnum = new BytesRefFSTEnum<>(fst);
return new SortedDocValues() {
final BytesRef term = new BytesRef();
@Override
public int getOrd(int docID) {
return (int) docToOrd.get(docID);
}
@Override
public BytesRef lookupOrd(int ord) {
try {
in.setPosition(0);
fst.getFirstArc(firstArc);
IntsRef output = Util.getByOutput(fst, ord, in, firstArc, scratchArc, scratchInts);
Util.toBytesRef(output, term);
return term;
} catch (IOException bogus) {
throw new RuntimeException(bogus);
}
}
@Override
public int lookupTerm(BytesRef key) {
try {
InputOutput<Long> o = fstEnum.seekCeil(key);
if (o == null) {
return -getValueCount()-1;
} else if (o.input.equals(key)) {
return o.output.intValue();
} else {
return (int) -o.output-1;
}
} catch (IOException bogus) {
throw new RuntimeException(bogus);
}
}
@Override
public int getValueCount() {
return (int)entry.numOrds;
}
@Override
public TermsEnum termsEnum() {
return new FSTTermsEnum(fst);
}
};
}
@Override
public SortedNumericDocValues getSortedNumeric(FieldInfo field) throws IOException {
SortedNumericEntry entry = sortedNumerics.get(field.number);
if (entry.singleton) {
NumericDocValues values = getNumeric(field);
NumericEntry ne = numerics.get(field.number);
Bits docsWithField = getMissingBits(field.number, ne.missingOffset, ne.missingBytes);
return DocValues.singleton(values, docsWithField);
} else {
final NumericDocValues values = getNumeric(field);
final MonotonicBlockPackedReader addr;
synchronized (this) {
MonotonicBlockPackedReader res = addresses.get(field.number);
if (res == null) {
data.seek(entry.addressOffset);
res = MonotonicBlockPackedReader.of(data, entry.packedIntsVersion, entry.blockSize, entry.valueCount, false);
addresses.put(field.number, res);
}
addr = res;
}
if (values instanceof LongValues) {
// probably not the greatest codec choice for this situation, but we support it
final LongValues longValues = (LongValues) values;
return new SortedNumericDocValues() {
long startOffset;
long endOffset;
@Override
public void setDocument(int doc) {
startOffset = (int) addr.get(doc);
endOffset = (int) addr.get(doc+1L);
}
@Override
public long valueAt(int index) {
return longValues.get(startOffset + index);
}
@Override
public int count() {
return (int) (endOffset - startOffset);
}
};
} else {
return new SortedNumericDocValues() {
int startOffset;
int endOffset;
@Override
public void setDocument(int doc) {
startOffset = (int) addr.get(doc);
endOffset = (int) addr.get(doc+1);
}
@Override
public long valueAt(int index) {
return values.get(startOffset + index);
}
@Override
public int count() {
return (endOffset - startOffset);
}
};
}
}
}
@Override
public SortedSetDocValues getSortedSet(FieldInfo field) throws IOException {
SortedSetEntry sortedSetEntry = sortedSets.get(field.number);
if (sortedSetEntry.singleton) {
return DocValues.singleton(getSorted(field));
}
final FSTEntry entry = fsts.get(field.number);
if (entry.numOrds == 0) {
return DocValues.emptySortedSet(); // empty FST!
}
FST<Long> instance;
synchronized(this) {
instance = fstInstances.get(field.number);
if (instance == null) {
data.seek(entry.offset);
instance = new FST<>(data, PositiveIntOutputs.getSingleton());
ramBytesUsed.addAndGet(instance.ramBytesUsed());
fstInstances.put(field.number, instance);
}
}
final BinaryDocValues docToOrds = getBinary(field);
final FST<Long> fst = instance;
// per-thread resources
final BytesReader in = fst.getBytesReader();
final Arc<Long> firstArc = new Arc<>();
final Arc<Long> scratchArc = new Arc<>();
final IntsRef scratchInts = new IntsRef();
final BytesRefFSTEnum<Long> fstEnum = new BytesRefFSTEnum<>(fst);
final ByteArrayDataInput input = new ByteArrayDataInput();
return new SortedSetDocValues() {
final BytesRef term = new BytesRef();
BytesRef ref;
long currentOrd;
@Override
public long nextOrd() {
if (input.eof()) {
return NO_MORE_ORDS;
} else {
currentOrd += input.readVLong();
return currentOrd;
}
}
@Override
public void setDocument(int docID) {
ref = docToOrds.get(docID);
input.reset(ref.bytes, ref.offset, ref.length);
currentOrd = 0;
}
@Override
public BytesRef lookupOrd(long ord) {
try {
in.setPosition(0);
fst.getFirstArc(firstArc);
IntsRef output = Util.getByOutput(fst, ord, in, firstArc, scratchArc, scratchInts);
Util.toBytesRef(output, term);
return term;
} catch (IOException bogus) {
throw new RuntimeException(bogus);
}
}
@Override
public long lookupTerm(BytesRef key) {
try {
InputOutput<Long> o = fstEnum.seekCeil(key);
if (o == null) {
return -getValueCount()-1;
} else if (o.input.equals(key)) {
return o.output.intValue();
} else {
return -o.output-1;
}
} catch (IOException bogus) {
throw new RuntimeException(bogus);
}
}
@Override
public long getValueCount() {
return entry.numOrds;
}
@Override
public TermsEnum termsEnum() {
return new FSTTermsEnum(fst);
}
};
}
private Bits getMissingBits(int fieldNumber, final long offset, final long length) throws IOException {
if (offset == -1) {
return new Bits.MatchAllBits(maxDoc);
} else {
Bits instance;
synchronized(this) {
instance = docsWithFieldInstances.get(fieldNumber);
if (instance == null) {
IndexInput data = this.data.clone();
data.seek(offset);
assert length % 8 == 0;
long bits[] = new long[(int) length >> 3];
for (int i = 0; i < bits.length; i++) {
bits[i] = data.readLong();
}
instance = new FixedBitSet(bits, maxDoc);
docsWithFieldInstances.put(fieldNumber, instance);
}
}
return instance;
}
}
@Override
public Bits getDocsWithField(FieldInfo field) throws IOException {
switch(field.getDocValuesType()) {
case SORTED_SET:
return DocValues.docsWithValue(getSortedSet(field), maxDoc);
case SORTED_NUMERIC:
return DocValues.docsWithValue(getSortedNumeric(field), maxDoc);
case SORTED:
return DocValues.docsWithValue(getSorted(field), maxDoc);
case BINARY:
BinaryEntry be = binaries.get(field.number);
return getMissingBits(field.number, be.missingOffset, be.missingBytes);
case NUMERIC:
NumericEntry ne = numerics.get(field.number);
return getMissingBits(field.number, ne.missingOffset, ne.missingBytes);
default:
throw new AssertionError();
}
}
@Override
public void close() throws IOException {
data.close();
}
static class NumericEntry {
long offset;
long count;
long missingOffset;
long missingBytes;
byte format;
int packedIntsVersion;
}
static class BinaryEntry {
long offset;
long missingOffset;
long missingBytes;
long numBytes;
int minLength;
int maxLength;
int packedIntsVersion;
int blockSize;
}
static class FSTEntry {
long offset;
long numOrds;
}
static class SortedSetEntry {
boolean singleton;
}
static class SortedNumericEntry {
boolean singleton;
long addressOffset;
int packedIntsVersion;
int blockSize;
long valueCount;
}
static class BytesAndAddresses {
PagedBytes.Reader reader;
MonotonicBlockPackedReader addresses;
}
// exposes FSTEnum directly as a TermsEnum: avoids binary-search next()
static class FSTTermsEnum extends TermsEnum {
final BytesRefFSTEnum<Long> in;
// this is all for the complicated seek(ord)...
// maybe we should add a FSTEnum that supports this operation?
final FST<Long> fst;
final FST.BytesReader bytesReader;
final Arc<Long> firstArc = new Arc<>();
final Arc<Long> scratchArc = new Arc<>();
final IntsRef scratchInts = new IntsRef();
final BytesRef scratchBytes = new BytesRef();
FSTTermsEnum(FST<Long> fst) {
this.fst = fst;
in = new BytesRefFSTEnum<>(fst);
bytesReader = fst.getBytesReader();
}
@Override
public BytesRef next() throws IOException {
InputOutput<Long> io = in.next();
if (io == null) {
return null;
} else {
return io.input;
}
}
@Override
public Comparator<BytesRef> getComparator() {
return BytesRef.getUTF8SortedAsUnicodeComparator();
}
@Override
public SeekStatus seekCeil(BytesRef text) throws IOException {
if (in.seekCeil(text) == null) {
return SeekStatus.END;
} else if (term().equals(text)) {
// TODO: add SeekStatus to FSTEnum like in https://issues.apache.org/jira/browse/LUCENE-3729
// to remove this comparision?
return SeekStatus.FOUND;
} else {
return SeekStatus.NOT_FOUND;
}
}
@Override
public boolean seekExact(BytesRef text) throws IOException {
if (in.seekExact(text) == null) {
return false;
} else {
return true;
}
}
@Override
public void seekExact(long ord) throws IOException {
// TODO: would be better to make this simpler and faster.
// but we dont want to introduce a bug that corrupts our enum state!
bytesReader.setPosition(0);
fst.getFirstArc(firstArc);
IntsRef output = Util.getByOutput(fst, ord, bytesReader, firstArc, scratchArc, scratchInts);
scratchBytes.bytes = new byte[output.length];
scratchBytes.offset = 0;
scratchBytes.length = 0;
Util.toBytesRef(output, scratchBytes);
// TODO: we could do this lazily, better to try to push into FSTEnum though?
in.seekExact(scratchBytes);
}
@Override
public BytesRef term() throws IOException {
return in.current().input;
}
@Override
public long ord() throws IOException {
return in.current().output;
}
@Override
public int docFreq() throws IOException {
throw new UnsupportedOperationException();
}
@Override
public long totalTermFreq() throws IOException {
throw new UnsupportedOperationException();
}
@Override
public DocsEnum docs(Bits liveDocs, DocsEnum reuse, int flags) throws IOException {
throw new UnsupportedOperationException();
}
@Override
public DocsAndPositionsEnum docsAndPositions(Bits liveDocs, DocsAndPositionsEnum reuse, int flags) throws IOException {
throw new UnsupportedOperationException();
}
}
}