package org.apache.lucene.index;
/**
* 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.FileNotFoundException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.FieldSelector;
import org.apache.lucene.search.DefaultSimilarity;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.Lock;
import org.apache.lucene.store.LockObtainFailedException;
import org.apache.lucene.search.FieldCache; // not great (circular); used only to purge FieldCache entry on close
/**
* An IndexReader which reads indexes with multiple segments.
*/
class DirectoryReader extends IndexReader implements Cloneable {
protected Directory directory;
protected boolean readOnly;
IndexWriter writer;
private IndexDeletionPolicy deletionPolicy;
private final HashSet<String> synced = new HashSet<String>();
private Lock writeLock;
private SegmentInfos segmentInfos;
private SegmentInfos segmentInfosStart;
private boolean stale;
private final int termInfosIndexDivisor;
private boolean rollbackHasChanges;
private SegmentReader[] subReaders;
private int[] starts; // 1st docno for each segment
private Map<String,byte[]> normsCache = new HashMap<String,byte[]>();
private int maxDoc = 0;
private int numDocs = -1;
private boolean hasDeletions = false;
// Max version in index as of when we opened; this can be
// > our current segmentInfos version in case we were
// opened on a past IndexCommit:
private long maxIndexVersion;
static IndexReader open(final Directory directory, final IndexDeletionPolicy deletionPolicy, final IndexCommit commit, final boolean readOnly,
final int termInfosIndexDivisor) throws CorruptIndexException, IOException {
return (IndexReader) new SegmentInfos.FindSegmentsFile(directory) {
@Override
protected Object doBody(String segmentFileName) throws CorruptIndexException, IOException {
SegmentInfos infos = new SegmentInfos();
infos.read(directory, segmentFileName);
if (readOnly)
return new ReadOnlyDirectoryReader(directory, infos, deletionPolicy, termInfosIndexDivisor);
else
return new DirectoryReader(directory, infos, deletionPolicy, false, termInfosIndexDivisor);
}
}.run(commit);
}
/** Construct reading the named set of readers. */
DirectoryReader(Directory directory, SegmentInfos sis, IndexDeletionPolicy deletionPolicy, boolean readOnly, int termInfosIndexDivisor) throws IOException {
this.directory = directory;
this.readOnly = readOnly;
this.segmentInfos = sis;
this.deletionPolicy = deletionPolicy;
this.termInfosIndexDivisor = termInfosIndexDivisor;
if (!readOnly) {
// We assume that this segments_N was previously
// properly sync'd:
synced.addAll(sis.files(directory, true));
}
// To reduce the chance of hitting FileNotFound
// (and having to retry), we open segments in
// reverse because IndexWriter merges & deletes
// the newest segments first.
SegmentReader[] readers = new SegmentReader[sis.size()];
for (int i = sis.size()-1; i >= 0; i--) {
boolean success = false;
try {
readers[i] = SegmentReader.get(readOnly, sis.info(i), termInfosIndexDivisor);
success = true;
} finally {
if (!success) {
// Close all readers we had opened:
for(i++;i<sis.size();i++) {
try {
readers[i].close();
} catch (Throwable ignore) {
// keep going - we want to clean up as much as possible
}
}
}
}
}
initialize(readers);
}
// Used by near real-time search
DirectoryReader(IndexWriter writer, SegmentInfos infos, int termInfosIndexDivisor) throws IOException {
this.directory = writer.getDirectory();
this.readOnly = true;
segmentInfos = infos;
segmentInfosStart = (SegmentInfos) infos.clone();
this.termInfosIndexDivisor = termInfosIndexDivisor;
if (!readOnly) {
// We assume that this segments_N was previously
// properly sync'd:
synced.addAll(infos.files(directory, true));
}
// IndexWriter synchronizes externally before calling
// us, which ensures infos will not change; so there's
// no need to process segments in reverse order
final int numSegments = infos.size();
SegmentReader[] readers = new SegmentReader[numSegments];
final Directory dir = writer.getDirectory();
int upto = 0;
for (int i=0;i<numSegments;i++) {
boolean success = false;
try {
final SegmentInfo info = infos.info(i);
if (info.dir == dir) {
readers[upto++] = writer.readerPool.getReadOnlyClone(info, true, termInfosIndexDivisor);
}
success = true;
} finally {
if (!success) {
// Close all readers we had opened:
for(upto--;upto>=0;upto--) {
try {
readers[upto].close();
} catch (Throwable ignore) {
// keep going - we want to clean up as much as possible
}
}
}
}
}
this.writer = writer;
if (upto < readers.length) {
// This means some segments were in a foreign Directory
SegmentReader[] newReaders = new SegmentReader[upto];
System.arraycopy(readers, 0, newReaders, 0, upto);
readers = newReaders;
}
initialize(readers);
}
/** This constructor is only used for {@link #reopen()} */
DirectoryReader(Directory directory, SegmentInfos infos, SegmentReader[] oldReaders, int[] oldStarts,
Map<String,byte[]> oldNormsCache, boolean readOnly, boolean doClone, int termInfosIndexDivisor) throws IOException {
this.directory = directory;
this.readOnly = readOnly;
this.segmentInfos = infos;
this.termInfosIndexDivisor = termInfosIndexDivisor;
if (!readOnly) {
// We assume that this segments_N was previously
// properly sync'd:
synced.addAll(infos.files(directory, true));
}
// we put the old SegmentReaders in a map, that allows us
// to lookup a reader using its segment name
Map<String,Integer> segmentReaders = new HashMap<String,Integer>();
if (oldReaders != null) {
// create a Map SegmentName->SegmentReader
for (int i = 0; i < oldReaders.length; i++) {
segmentReaders.put(oldReaders[i].getSegmentName(), Integer.valueOf(i));
}
}
SegmentReader[] newReaders = new SegmentReader[infos.size()];
// remember which readers are shared between the old and the re-opened
// DirectoryReader - we have to incRef those readers
boolean[] readerShared = new boolean[infos.size()];
for (int i = infos.size() - 1; i>=0; i--) {
// find SegmentReader for this segment
Integer oldReaderIndex = segmentReaders.get(infos.info(i).name);
if (oldReaderIndex == null) {
// this is a new segment, no old SegmentReader can be reused
newReaders[i] = null;
} else {
// there is an old reader for this segment - we'll try to reopen it
newReaders[i] = oldReaders[oldReaderIndex.intValue()];
}
boolean success = false;
try {
SegmentReader newReader;
if (newReaders[i] == null || infos.info(i).getUseCompoundFile() != newReaders[i].getSegmentInfo().getUseCompoundFile()) {
// We should never see a totally new segment during cloning
assert !doClone;
// this is a new reader; in case we hit an exception we can close it safely
newReader = SegmentReader.get(readOnly, infos.info(i), termInfosIndexDivisor);
} else {
newReader = newReaders[i].reopenSegment(infos.info(i), doClone, readOnly);
}
if (newReader == newReaders[i]) {
// this reader will be shared between the old and the new one,
// so we must incRef it
readerShared[i] = true;
newReader.incRef();
} else {
readerShared[i] = false;
newReaders[i] = newReader;
}
success = true;
} finally {
if (!success) {
for (i++; i < infos.size(); i++) {
if (newReaders[i] != null) {
try {
if (!readerShared[i]) {
// this is a new subReader that is not used by the old one,
// we can close it
newReaders[i].close();
} else {
// this subReader is also used by the old reader, so instead
// closing we must decRef it
newReaders[i].decRef();
}
} catch (IOException ignore) {
// keep going - we want to clean up as much as possible
}
}
}
}
}
}
// initialize the readers to calculate maxDoc before we try to reuse the old normsCache
initialize(newReaders);
// try to copy unchanged norms from the old normsCache to the new one
if (oldNormsCache != null) {
for (Map.Entry<String,byte[]> entry: oldNormsCache.entrySet()) {
String field = entry.getKey();
if (!hasNorms(field)) {
continue;
}
byte[] oldBytes = entry.getValue();
byte[] bytes = new byte[maxDoc()];
for (int i = 0; i < subReaders.length; i++) {
Integer oldReaderIndex = segmentReaders.get(subReaders[i].getSegmentName());
// this SegmentReader was not re-opened, we can copy all of its norms
if (oldReaderIndex != null &&
(oldReaders[oldReaderIndex.intValue()] == subReaders[i]
|| oldReaders[oldReaderIndex.intValue()].norms.get(field) == subReaders[i].norms.get(field))) {
// we don't have to synchronize here: either this constructor is called from a SegmentReader,
// in which case no old norms cache is present, or it is called from MultiReader.reopen(),
// which is synchronized
System.arraycopy(oldBytes, oldStarts[oldReaderIndex.intValue()], bytes, starts[i], starts[i+1] - starts[i]);
} else {
subReaders[i].norms(field, bytes, starts[i]);
}
}
normsCache.put(field, bytes); // update cache
}
}
}
private void initialize(SegmentReader[] subReaders) throws IOException {
this.subReaders = subReaders;
starts = new int[subReaders.length + 1]; // build starts array
for (int i = 0; i < subReaders.length; i++) {
starts[i] = maxDoc;
maxDoc += subReaders[i].maxDoc(); // compute maxDocs
if (subReaders[i].hasDeletions())
hasDeletions = true;
}
starts[subReaders.length] = maxDoc;
if (!readOnly) {
maxIndexVersion = SegmentInfos.readCurrentVersion(directory);
}
}
@Override
public final synchronized Object clone() {
try {
return clone(readOnly); // Preserve current readOnly
} catch (Exception ex) {
throw new RuntimeException(ex);
}
}
@Override
public final synchronized IndexReader clone(boolean openReadOnly) throws CorruptIndexException, IOException {
DirectoryReader newReader = doReopen((SegmentInfos) segmentInfos.clone(), true, openReadOnly);
if (this != newReader) {
newReader.deletionPolicy = deletionPolicy;
}
newReader.writer = writer;
// If we're cloning a non-readOnly reader, move the
// writeLock (if there is one) to the new reader:
if (!openReadOnly && writeLock != null) {
// In near real-time search, reader is always readonly
assert writer == null;
newReader.writeLock = writeLock;
newReader.hasChanges = hasChanges;
newReader.hasDeletions = hasDeletions;
writeLock = null;
hasChanges = false;
}
return newReader;
}
@Override
public final IndexReader reopen() throws CorruptIndexException, IOException {
// Preserve current readOnly
return doReopen(readOnly, null);
}
@Override
public final IndexReader reopen(boolean openReadOnly) throws CorruptIndexException, IOException {
return doReopen(openReadOnly, null);
}
@Override
public final IndexReader reopen(final IndexCommit commit) throws CorruptIndexException, IOException {
return doReopen(true, commit);
}
private final IndexReader doReopenFromWriter(boolean openReadOnly, IndexCommit commit) throws CorruptIndexException, IOException {
assert readOnly;
if (!openReadOnly) {
throw new IllegalArgumentException("a reader obtained from IndexWriter.getReader() can only be reopened with openReadOnly=true (got false)");
}
if (commit != null) {
throw new IllegalArgumentException("a reader obtained from IndexWriter.getReader() cannot currently accept a commit");
}
// TODO: right now we *always* make a new reader; in
// the future we could have write make some effort to
// detect that no changes have occurred
return writer.getReader();
}
private IndexReader doReopen(final boolean openReadOnly, IndexCommit commit) throws CorruptIndexException, IOException {
ensureOpen();
assert commit == null || openReadOnly;
// If we were obtained by writer.getReader(), re-ask the
// writer to get a new reader.
if (writer != null) {
return doReopenFromWriter(openReadOnly, commit);
} else {
return doReopenNoWriter(openReadOnly, commit);
}
}
private synchronized IndexReader doReopenNoWriter(final boolean openReadOnly, IndexCommit commit) throws CorruptIndexException, IOException {
if (commit == null) {
if (hasChanges) {
// We have changes, which means we are not readOnly:
assert readOnly == false;
// and we hold the write lock:
assert writeLock != null;
// so no other writer holds the write lock, which
// means no changes could have been done to the index:
assert isCurrent();
if (openReadOnly) {
return clone(openReadOnly);
} else {
return this;
}
} else if (isCurrent()) {
if (openReadOnly != readOnly) {
// Just fallback to clone
return clone(openReadOnly);
} else {
return this;
}
}
} else {
if (directory != commit.getDirectory())
throw new IOException("the specified commit does not match the specified Directory");
if (segmentInfos != null && commit.getSegmentsFileName().equals(segmentInfos.getCurrentSegmentFileName())) {
if (readOnly != openReadOnly) {
// Just fallback to clone
return clone(openReadOnly);
} else {
return this;
}
}
}
return (IndexReader) new SegmentInfos.FindSegmentsFile(directory) {
@Override
protected Object doBody(String segmentFileName) throws CorruptIndexException, IOException {
SegmentInfos infos = new SegmentInfos();
infos.read(directory, segmentFileName);
return doReopen(infos, false, openReadOnly);
}
}.run(commit);
}
private synchronized DirectoryReader doReopen(SegmentInfos infos, boolean doClone, boolean openReadOnly) throws CorruptIndexException, IOException {
DirectoryReader reader;
if (openReadOnly) {
reader = new ReadOnlyDirectoryReader(directory, infos, subReaders, starts, normsCache, doClone, termInfosIndexDivisor);
} else {
reader = new DirectoryReader(directory, infos, subReaders, starts, normsCache, false, doClone, termInfosIndexDivisor);
}
return reader;
}
/** Version number when this IndexReader was opened. */
@Override
public long getVersion() {
ensureOpen();
return segmentInfos.getVersion();
}
@Override
public TermFreqVector[] getTermFreqVectors(int n) throws IOException {
ensureOpen();
int i = readerIndex(n); // find segment num
return subReaders[i].getTermFreqVectors(n - starts[i]); // dispatch to segment
}
@Override
public TermFreqVector getTermFreqVector(int n, String field)
throws IOException {
ensureOpen();
int i = readerIndex(n); // find segment num
return subReaders[i].getTermFreqVector(n - starts[i], field);
}
@Override
public void getTermFreqVector(int docNumber, String field, TermVectorMapper mapper) throws IOException {
ensureOpen();
int i = readerIndex(docNumber); // find segment num
subReaders[i].getTermFreqVector(docNumber - starts[i], field, mapper);
}
@Override
public void getTermFreqVector(int docNumber, TermVectorMapper mapper) throws IOException {
ensureOpen();
int i = readerIndex(docNumber); // find segment num
subReaders[i].getTermFreqVector(docNumber - starts[i], mapper);
}
/**
* Checks is the index is optimized (if it has a single segment and no deletions)
* @return <code>true</code> if the index is optimized; <code>false</code> otherwise
*/
@Override
public boolean isOptimized() {
ensureOpen();
return segmentInfos.size() == 1 && !hasDeletions();
}
@Override
public int numDocs() {
// Don't call ensureOpen() here (it could affect performance)
// NOTE: multiple threads may wind up init'ing
// numDocs... but that's harmless
if (numDocs == -1) { // check cache
int n = 0; // cache miss--recompute
for (int i = 0; i < subReaders.length; i++)
n += subReaders[i].numDocs(); // sum from readers
numDocs = n;
}
return numDocs;
}
@Override
public int maxDoc() {
// Don't call ensureOpen() here (it could affect performance)
return maxDoc;
}
// inherit javadoc
@Override
public Document document(int n, FieldSelector fieldSelector) throws CorruptIndexException, IOException {
ensureOpen();
int i = readerIndex(n); // find segment num
return subReaders[i].document(n - starts[i], fieldSelector); // dispatch to segment reader
}
@Override
public boolean isDeleted(int n) {
// Don't call ensureOpen() here (it could affect performance)
final int i = readerIndex(n); // find segment num
return subReaders[i].isDeleted(n - starts[i]); // dispatch to segment reader
}
@Override
public boolean hasDeletions() {
// Don't call ensureOpen() here (it could affect performance)
return hasDeletions;
}
@Override
protected void doDelete(int n) throws CorruptIndexException, IOException {
numDocs = -1; // invalidate cache
int i = readerIndex(n); // find segment num
subReaders[i].deleteDocument(n - starts[i]); // dispatch to segment reader
hasDeletions = true;
}
@Override
protected void doUndeleteAll() throws CorruptIndexException, IOException {
for (int i = 0; i < subReaders.length; i++)
subReaders[i].undeleteAll();
hasDeletions = false;
numDocs = -1; // invalidate cache
}
private int readerIndex(int n) { // find reader for doc n:
return readerIndex(n, this.starts, this.subReaders.length);
}
final static int readerIndex(int n, int[] starts, int numSubReaders) { // find reader for doc n:
int lo = 0; // search starts array
int hi = numSubReaders - 1; // for first element less
while (hi >= lo) {
int mid = (lo + hi) >>> 1;
int midValue = starts[mid];
if (n < midValue)
hi = mid - 1;
else if (n > midValue)
lo = mid + 1;
else { // found a match
while (mid+1 < numSubReaders && starts[mid+1] == midValue) {
mid++; // scan to last match
}
return mid;
}
}
return hi;
}
@Override
public boolean hasNorms(String field) throws IOException {
ensureOpen();
for (int i = 0; i < subReaders.length; i++) {
if (subReaders[i].hasNorms(field)) return true;
}
return false;
}
@Override
public synchronized byte[] norms(String field) throws IOException {
ensureOpen();
byte[] bytes = normsCache.get(field);
if (bytes != null)
return bytes; // cache hit
if (!hasNorms(field))
return null;
bytes = new byte[maxDoc()];
for (int i = 0; i < subReaders.length; i++)
subReaders[i].norms(field, bytes, starts[i]);
normsCache.put(field, bytes); // update cache
return bytes;
}
@Override
public synchronized void norms(String field, byte[] result, int offset)
throws IOException {
ensureOpen();
byte[] bytes = normsCache.get(field);
if (bytes==null && !hasNorms(field)) {
Arrays.fill(result, offset, result.length, DefaultSimilarity.encodeNorm(1.0f));
} else if (bytes != null) { // cache hit
System.arraycopy(bytes, 0, result, offset, maxDoc());
} else {
for (int i = 0; i < subReaders.length; i++) { // read from segments
subReaders[i].norms(field, result, offset + starts[i]);
}
}
}
@Override
protected void doSetNorm(int n, String field, byte value)
throws CorruptIndexException, IOException {
synchronized (normsCache) {
normsCache.remove(field); // clear cache
}
int i = readerIndex(n); // find segment num
subReaders[i].setNorm(n-starts[i], field, value); // dispatch
}
@Override
public TermEnum terms() throws IOException {
ensureOpen();
return new MultiTermEnum(this, subReaders, starts, null);
}
@Override
public TermEnum terms(Term term) throws IOException {
ensureOpen();
return new MultiTermEnum(this, subReaders, starts, term);
}
@Override
public int docFreq(Term t) throws IOException {
ensureOpen();
int total = 0; // sum freqs in segments
for (int i = 0; i < subReaders.length; i++)
total += subReaders[i].docFreq(t);
return total;
}
@Override
public TermDocs termDocs() throws IOException {
ensureOpen();
return new MultiTermDocs(this, subReaders, starts);
}
@Override
public TermPositions termPositions() throws IOException {
ensureOpen();
return new MultiTermPositions(this, subReaders, starts);
}
/**
* Tries to acquire the WriteLock on this directory. this method is only valid if this IndexReader is directory
* owner.
*
* @throws StaleReaderException if the index has changed since this reader was opened
* @throws CorruptIndexException if the index is corrupt
* @throws org.apache.lucene.store.LockObtainFailedException
* if another writer has this index open (<code>write.lock</code> could not be
* obtained)
* @throws IOException if there is a low-level IO error
*/
@Override
protected void acquireWriteLock() throws StaleReaderException, CorruptIndexException, LockObtainFailedException, IOException {
if (readOnly) {
// NOTE: we should not reach this code w/ the core
// IndexReader classes; however, an external subclass
// of IndexReader could reach this.
ReadOnlySegmentReader.noWrite();
}
if (segmentInfos != null) {
ensureOpen();
if (stale)
throw new StaleReaderException("IndexReader out of date and no longer valid for delete, undelete, or setNorm operations");
if (writeLock == null) {
Lock writeLock = directory.makeLock(IndexWriter.WRITE_LOCK_NAME);
if (!writeLock.obtain(IndexWriter.WRITE_LOCK_TIMEOUT)) // obtain write lock
throw new LockObtainFailedException("Index locked for write: " + writeLock);
this.writeLock = writeLock;
// we have to check whether index has changed since this reader was opened.
// if so, this reader is no longer valid for
// deletion
if (SegmentInfos.readCurrentVersion(directory) > maxIndexVersion) {
stale = true;
this.writeLock.release();
this.writeLock = null;
throw new StaleReaderException("IndexReader out of date and no longer valid for delete, undelete, or setNorm operations");
}
}
}
}
/**
* Commit changes resulting from delete, undeleteAll, or setNorm operations
* <p/>
* If an exception is hit, then either no changes or all changes will have been committed to the index (transactional
* semantics).
*
* @throws IOException if there is a low-level IO error
*/
@Override
protected void doCommit(Map<String,String> commitUserData) throws IOException {
if (hasChanges) {
segmentInfos.setUserData(commitUserData);
// Default deleter (for backwards compatibility) is
// KeepOnlyLastCommitDeleter:
IndexFileDeleter deleter = new IndexFileDeleter(directory,
deletionPolicy == null ? new KeepOnlyLastCommitDeletionPolicy() : deletionPolicy,
segmentInfos, null, null, synced);
segmentInfos.updateGeneration(deleter.getLastSegmentInfos());
// Checkpoint the state we are about to change, in
// case we have to roll back:
startCommit();
boolean success = false;
try {
for (int i = 0; i < subReaders.length; i++)
subReaders[i].commit();
// Sync all files we just wrote
final Collection<String> files = segmentInfos.files(directory, false);
for (final String fileName : files) {
if (!synced.contains(fileName)) {
assert directory.fileExists(fileName);
directory.sync(fileName);
synced.add(fileName);
}
}
segmentInfos.commit(directory);
success = true;
} finally {
if (!success) {
// Rollback changes that were made to
// SegmentInfos but failed to get [fully]
// committed. This way this reader instance
// remains consistent (matched to what's
// actually in the index):
rollbackCommit();
// Recompute deletable files & remove them (so
// partially written .del files, etc, are
// removed):
deleter.refresh();
}
}
// Have the deleter remove any now unreferenced
// files due to this commit:
deleter.checkpoint(segmentInfos, true);
deleter.close();
maxIndexVersion = segmentInfos.getVersion();
if (writeLock != null) {
writeLock.release(); // release write lock
writeLock = null;
}
}
hasChanges = false;
}
void startCommit() {
rollbackHasChanges = hasChanges;
for (int i = 0; i < subReaders.length; i++) {
subReaders[i].startCommit();
}
}
void rollbackCommit() {
hasChanges = rollbackHasChanges;
for (int i = 0; i < subReaders.length; i++) {
subReaders[i].rollbackCommit();
}
}
@Override
public Map<String,String> getCommitUserData() {
ensureOpen();
return segmentInfos.getUserData();
}
@Override
public boolean isCurrent() throws CorruptIndexException, IOException {
ensureOpen();
if (writer == null || writer.isClosed()) {
// we loaded SegmentInfos from the directory
return SegmentInfos.readCurrentVersion(directory) == segmentInfos.getVersion();
} else {
return writer.nrtIsCurrent(segmentInfosStart);
}
}
@Override
protected synchronized void doClose() throws IOException {
IOException ioe = null;
normsCache = null;
for (int i = 0; i < subReaders.length; i++) {
// try to close each reader, even if an exception is thrown
try {
subReaders[i].decRef();
} catch (IOException e) {
if (ioe == null) ioe = e;
}
}
// NOTE: only needed in case someone had asked for
// FieldCache for top-level reader (which is generally
// not a good idea):
FieldCache.DEFAULT.purge(this);
// throw the first exception
if (ioe != null) throw ioe;
}
@Override
public Collection<String> getFieldNames (IndexReader.FieldOption fieldNames) {
ensureOpen();
return getFieldNames(fieldNames, this.subReaders);
}
static Collection<String> getFieldNames (IndexReader.FieldOption fieldNames, IndexReader[] subReaders) {
// maintain a unique set of field names
Set<String> fieldSet = new HashSet<String>();
for (IndexReader reader : subReaders) {
Collection<String> names = reader.getFieldNames(fieldNames);
fieldSet.addAll(names);
}
return fieldSet;
}
@Override
public IndexReader[] getSequentialSubReaders() {
return subReaders;
}
/** Returns the directory this index resides in. */
@Override
public Directory directory() {
// Don't ensureOpen here -- in certain cases, when a
// cloned/reopened reader needs to commit, it may call
// this method on the closed original reader
return directory;
}
@Override
public int getTermInfosIndexDivisor() {
return termInfosIndexDivisor;
}
/**
* Expert: return the IndexCommit that this reader has opened.
* <p/>
* <p><b>WARNING</b>: this API is new and experimental and may suddenly change.</p>
*/
@Override
public IndexCommit getIndexCommit() throws IOException {
return new ReaderCommit(segmentInfos, directory);
}
/** @see org.apache.lucene.index.IndexReader#listCommits */
public static Collection<IndexCommit> listCommits(Directory dir) throws IOException {
final String[] files = dir.listAll();
Collection<IndexCommit> commits = new ArrayList<IndexCommit>();
SegmentInfos latest = new SegmentInfos();
latest.read(dir);
final long currentGen = latest.getGeneration();
commits.add(new ReaderCommit(latest, dir));
for(int i=0;i<files.length;i++) {
final String fileName = files[i];
if (fileName.startsWith(IndexFileNames.SEGMENTS) &&
!fileName.equals(IndexFileNames.SEGMENTS_GEN) &&
SegmentInfos.generationFromSegmentsFileName(fileName) < currentGen) {
SegmentInfos sis = new SegmentInfos();
try {
// IOException allowed to throw there, in case
// segments_N is corrupt
sis.read(dir, fileName);
} catch (FileNotFoundException fnfe) {
// LUCENE-948: on NFS (and maybe others), if
// you have writers switching back and forth
// between machines, it's very likely that the
// dir listing will be stale and will claim a
// file segments_X exists when in fact it
// doesn't. So, we catch this and handle it
// as if the file does not exist
sis = null;
}
if (sis != null)
commits.add(new ReaderCommit(sis, dir));
}
}
return commits;
}
private static final class ReaderCommit extends IndexCommit {
private String segmentsFileName;
Collection<String> files;
Directory dir;
long generation;
long version;
final boolean isOptimized;
final Map<String,String> userData;
ReaderCommit(SegmentInfos infos, Directory dir) throws IOException {
segmentsFileName = infos.getCurrentSegmentFileName();
this.dir = dir;
userData = infos.getUserData();
files = Collections.unmodifiableCollection(infos.files(dir, true));
version = infos.getVersion();
generation = infos.getGeneration();
isOptimized = infos.size() == 1 && !infos.info(0).hasDeletions();
}
@Override
public String toString() {
return "DirectoryReader.ReaderCommit(" + segmentsFileName + ")";
}
@Override
public boolean isOptimized() {
return isOptimized;
}
@Override
public String getSegmentsFileName() {
return segmentsFileName;
}
@Override
public Collection<String> getFileNames() {
return files;
}
@Override
public Directory getDirectory() {
return dir;
}
@Override
public long getVersion() {
return version;
}
@Override
public long getGeneration() {
return generation;
}
@Override
public boolean isDeleted() {
return false;
}
@Override
public Map<String,String> getUserData() {
return userData;
}
@Override
public void delete() {
throw new UnsupportedOperationException("This IndexCommit does not support deletions");
}
}
static class MultiTermEnum extends TermEnum {
IndexReader topReader; // used for matching TermEnum to TermDocs
private SegmentMergeQueue queue;
private Term term;
private int docFreq;
final SegmentMergeInfo[] matchingSegments; // null terminated array of matching segments
public MultiTermEnum(IndexReader topReader, IndexReader[] readers, int[] starts, Term t)
throws IOException {
this.topReader = topReader;
queue = new SegmentMergeQueue(readers.length);
matchingSegments = new SegmentMergeInfo[readers.length+1];
for (int i = 0; i < readers.length; i++) {
IndexReader reader = readers[i];
TermEnum termEnum;
if (t != null) {
termEnum = reader.terms(t);
} else
termEnum = reader.terms();
SegmentMergeInfo smi = new SegmentMergeInfo(starts[i], termEnum, reader);
smi.ord = i;
if (t == null ? smi.next() : termEnum.term() != null)
queue.add(smi); // initialize queue
else
smi.close();
}
if (t != null && queue.size() > 0) {
next();
}
}
@Override
public boolean next() throws IOException {
for (int i=0; i<matchingSegments.length; i++) {
SegmentMergeInfo smi = matchingSegments[i];
if (smi==null) break;
if (smi.next())
queue.add(smi);
else
smi.close(); // done with segment
}
int numMatchingSegments = 0;
matchingSegments[0] = null;
SegmentMergeInfo top = queue.top();
if (top == null) {
term = null;
return false;
}
term = top.term;
docFreq = 0;
while (top != null && term.compareTo(top.term) == 0) {
matchingSegments[numMatchingSegments++] = top;
queue.pop();
docFreq += top.termEnum.docFreq(); // increment freq
top = queue.top();
}
matchingSegments[numMatchingSegments] = null;
return true;
}
@Override
public Term term() {
return term;
}
@Override
public int docFreq() {
return docFreq;
}
@Override
public void close() throws IOException {
queue.close();
}
}
static class MultiTermDocs implements TermDocs {
IndexReader topReader; // used for matching TermEnum to TermDocs
protected IndexReader[] readers;
protected int[] starts;
protected Term term;
protected int base = 0;
protected int pointer = 0;
private TermDocs[] readerTermDocs;
protected TermDocs current; // == readerTermDocs[pointer]
private MultiTermEnum tenum; // the term enum used for seeking... can be null
int matchingSegmentPos; // position into the matching segments from tenum
SegmentMergeInfo smi; // current segment mere info... can be null
public MultiTermDocs(IndexReader topReader, IndexReader[] r, int[] s) {
this.topReader = topReader;
readers = r;
starts = s;
readerTermDocs = new TermDocs[r.length];
}
public int doc() {
return base + current.doc();
}
public int freq() {
return current.freq();
}
public void seek(Term term) {
this.term = term;
this.base = 0;
this.pointer = 0;
this.current = null;
this.tenum = null;
this.smi = null;
this.matchingSegmentPos = 0;
}
public void seek(TermEnum termEnum) throws IOException {
seek(termEnum.term());
if (termEnum instanceof MultiTermEnum) {
tenum = (MultiTermEnum)termEnum;
if (topReader != tenum.topReader)
tenum = null;
}
}
public boolean next() throws IOException {
for(;;) {
if (current!=null && current.next()) {
return true;
}
else if (pointer < readers.length) {
if (tenum != null) {
smi = tenum.matchingSegments[matchingSegmentPos++];
if (smi==null) {
pointer = readers.length;
return false;
}
pointer = smi.ord;
}
base = starts[pointer];
current = termDocs(pointer++);
} else {
return false;
}
}
}
/** Optimized implementation. */
public int read(final int[] docs, final int[] freqs) throws IOException {
while (true) {
while (current == null) {
if (pointer < readers.length) { // try next segment
if (tenum != null) {
smi = tenum.matchingSegments[matchingSegmentPos++];
if (smi==null) {
pointer = readers.length;
return 0;
}
pointer = smi.ord;
}
base = starts[pointer];
current = termDocs(pointer++);
} else {
return 0;
}
}
int end = current.read(docs, freqs);
if (end == 0) { // none left in segment
current = null;
} else { // got some
final int b = base; // adjust doc numbers
for (int i = 0; i < end; i++)
docs[i] += b;
return end;
}
}
}
/* A Possible future optimization could skip entire segments */
public boolean skipTo(int target) throws IOException {
for(;;) {
if (current != null && current.skipTo(target-base)) {
return true;
} else if (pointer < readers.length) {
if (tenum != null) {
SegmentMergeInfo smi = tenum.matchingSegments[matchingSegmentPos++];
if (smi==null) {
pointer = readers.length;
return false;
}
pointer = smi.ord;
}
base = starts[pointer];
current = termDocs(pointer++);
} else
return false;
}
}
private TermDocs termDocs(int i) throws IOException {
TermDocs result = readerTermDocs[i];
if (result == null)
result = readerTermDocs[i] = termDocs(readers[i]);
if (smi != null) {
assert(smi.ord == i);
assert(smi.termEnum.term().equals(term));
result.seek(smi.termEnum);
} else {
result.seek(term);
}
return result;
}
protected TermDocs termDocs(IndexReader reader)
throws IOException {
return term==null ? reader.termDocs(null) : reader.termDocs();
}
public void close() throws IOException {
for (int i = 0; i < readerTermDocs.length; i++) {
if (readerTermDocs[i] != null)
readerTermDocs[i].close();
}
}
}
static class MultiTermPositions extends MultiTermDocs implements TermPositions {
public MultiTermPositions(IndexReader topReader, IndexReader[] r, int[] s) {
super(topReader,r,s);
}
@Override
protected TermDocs termDocs(IndexReader reader) throws IOException {
return reader.termPositions();
}
public int nextPosition() throws IOException {
return ((TermPositions)current).nextPosition();
}
public int getPayloadLength() {
return ((TermPositions)current).getPayloadLength();
}
public byte[] getPayload(byte[] data, int offset) throws IOException {
return ((TermPositions)current).getPayload(data, offset);
}
// TODO: Remove warning after API has been finalized
public boolean isPayloadAvailable() {
return ((TermPositions) current).isPayloadAvailable();
}
}
}