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.util.Vector;
import java.util.Iterator;
import java.util.Collection;
import java.io.IOException;
import org.apache.lucene.document.FieldSelector;
import org.apache.lucene.document.FieldSelectorResult;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.IndexOutput;
import org.apache.lucene.store.RAMOutputStream;
/**
* The SegmentMerger class combines two or more Segments, represented by an IndexReader ({@link #add},
* into a single Segment. After adding the appropriate readers, call the merge method to combine the
* segments.
*<P>
* If the compoundFile flag is set, then the segments will be merged into a compound file.
*
*
* @see #merge
* @see #add
*/
final class SegmentMerger {
/** norms header placeholder */
static final byte[] NORMS_HEADER = new byte[]{'N','R','M',-1};
private Directory directory;
private String segment;
private int termIndexInterval = IndexWriter.DEFAULT_TERM_INDEX_INTERVAL;
private Vector readers = new Vector();
private FieldInfos fieldInfos;
/** This ctor used only by test code.
*
* @param dir The Directory to merge the other segments into
* @param name The name of the new segment
*/
SegmentMerger(Directory dir, String name) {
directory = dir;
segment = name;
}
SegmentMerger(IndexWriter writer, String name) {
directory = writer.getDirectory();
segment = name;
termIndexInterval = writer.getTermIndexInterval();
}
/**
* Add an IndexReader to the collection of readers that are to be merged
* @param reader
*/
final void add(IndexReader reader) {
readers.addElement(reader);
}
/**
*
* @param i The index of the reader to return
* @return The ith reader to be merged
*/
final IndexReader segmentReader(int i) {
return (IndexReader) readers.elementAt(i);
}
/**
* Merges the readers specified by the {@link #add} method into the directory passed to the constructor
* @return The number of documents that were merged
* @throws IOException
*/
final int merge() throws IOException {
int value;
value = mergeFields();
mergeTerms();
mergeNorms();
if (fieldInfos.hasVectors())
mergeVectors();
return value;
}
/**
* close all IndexReaders that have been added.
* Should not be called before merge().
* @throws IOException
*/
final void closeReaders() throws IOException {
for (int i = 0; i < readers.size(); i++) { // close readers
IndexReader reader = (IndexReader) readers.elementAt(i);
reader.close();
}
}
final Vector createCompoundFile(String fileName)
throws IOException {
CompoundFileWriter cfsWriter =
new CompoundFileWriter(directory, fileName);
Vector files =
new Vector(IndexFileNames.COMPOUND_EXTENSIONS.length + 1);
// Basic files
for (int i = 0; i < IndexFileNames.COMPOUND_EXTENSIONS.length; i++) {
files.add(segment + "." + IndexFileNames.COMPOUND_EXTENSIONS[i]);
}
// Fieldable norm files
for (int i = 0; i < fieldInfos.size(); i++) {
FieldInfo fi = fieldInfos.fieldInfo(i);
if (fi.isIndexed && !fi.omitNorms) {
files.add(segment + "." + IndexFileNames.NORMS_EXTENSION);
break;
}
}
// Vector files
if (fieldInfos.hasVectors()) {
for (int i = 0; i < IndexFileNames.VECTOR_EXTENSIONS.length; i++) {
files.add(segment + "." + IndexFileNames.VECTOR_EXTENSIONS[i]);
}
}
// Now merge all added files
Iterator it = files.iterator();
while (it.hasNext()) {
cfsWriter.addFile((String) it.next());
}
// Perform the merge
cfsWriter.close();
return files;
}
private void addIndexed(IndexReader reader, FieldInfos fieldInfos, Collection names, boolean storeTermVectors, boolean storePositionWithTermVector,
boolean storeOffsetWithTermVector) throws IOException {
Iterator i = names.iterator();
while (i.hasNext()) {
String field = (String)i.next();
fieldInfos.add(field, true, storeTermVectors, storePositionWithTermVector, storeOffsetWithTermVector, !reader.hasNorms(field));
}
}
/**
*
* @return The number of documents in all of the readers
* @throws IOException
*/
private final int mergeFields() throws IOException {
fieldInfos = new FieldInfos(); // merge field names
int docCount = 0;
for (int i = 0; i < readers.size(); i++) {
IndexReader reader = (IndexReader) readers.elementAt(i);
addIndexed(reader, fieldInfos, reader.getFieldNames(IndexReader.FieldOption.TERMVECTOR_WITH_POSITION_OFFSET), true, true, true);
addIndexed(reader, fieldInfos, reader.getFieldNames(IndexReader.FieldOption.TERMVECTOR_WITH_POSITION), true, true, false);
addIndexed(reader, fieldInfos, reader.getFieldNames(IndexReader.FieldOption.TERMVECTOR_WITH_OFFSET), true, false, true);
addIndexed(reader, fieldInfos, reader.getFieldNames(IndexReader.FieldOption.TERMVECTOR), true, false, false);
addIndexed(reader, fieldInfos, reader.getFieldNames(IndexReader.FieldOption.INDEXED), false, false, false);
fieldInfos.add(reader.getFieldNames(IndexReader.FieldOption.UNINDEXED), false);
}
fieldInfos.write(directory, segment + ".fnm");
FieldsWriter fieldsWriter = // merge field values
new FieldsWriter(directory, segment, fieldInfos);
// for merging we don't want to compress/uncompress the data, so to tell the FieldsReader that we're
// in merge mode, we use this FieldSelector
FieldSelector fieldSelectorMerge = new FieldSelector() {
public FieldSelectorResult accept(String fieldName) {
return FieldSelectorResult.LOAD_FOR_MERGE;
}
};
try {
for (int i = 0; i < readers.size(); i++) {
IndexReader reader = (IndexReader) readers.elementAt(i);
int maxDoc = reader.maxDoc();
for (int j = 0; j < maxDoc; j++)
if (!reader.isDeleted(j)) { // skip deleted docs
fieldsWriter.addDocument(reader.document(j, fieldSelectorMerge));
docCount++;
}
}
} finally {
fieldsWriter.close();
}
return docCount;
}
/**
* Merge the TermVectors from each of the segments into the new one.
* @throws IOException
*/
private final void mergeVectors() throws IOException {
TermVectorsWriter termVectorsWriter =
new TermVectorsWriter(directory, segment, fieldInfos);
try {
for (int r = 0; r < readers.size(); r++) {
IndexReader reader = (IndexReader) readers.elementAt(r);
int maxDoc = reader.maxDoc();
for (int docNum = 0; docNum < maxDoc; docNum++) {
// skip deleted docs
if (reader.isDeleted(docNum))
continue;
termVectorsWriter.addAllDocVectors(reader.getTermFreqVectors(docNum));
}
}
} finally {
termVectorsWriter.close();
}
}
private IndexOutput freqOutput = null;
private IndexOutput proxOutput = null;
private TermInfosWriter termInfosWriter = null;
private int skipInterval;
private SegmentMergeQueue queue = null;
private final void mergeTerms() throws IOException {
try {
freqOutput = directory.createOutput(segment + ".frq");
proxOutput = directory.createOutput(segment + ".prx");
termInfosWriter =
new TermInfosWriter(directory, segment, fieldInfos,
termIndexInterval);
skipInterval = termInfosWriter.skipInterval;
queue = new SegmentMergeQueue(readers.size());
mergeTermInfos();
} finally {
if (freqOutput != null) freqOutput.close();
if (proxOutput != null) proxOutput.close();
if (termInfosWriter != null) termInfosWriter.close();
if (queue != null) queue.close();
}
}
private final void mergeTermInfos() throws IOException {
int base = 0;
for (int i = 0; i < readers.size(); i++) {
IndexReader reader = (IndexReader) readers.elementAt(i);
TermEnum termEnum = reader.terms();
SegmentMergeInfo smi = new SegmentMergeInfo(base, termEnum, reader);
base += reader.numDocs();
if (smi.next())
queue.put(smi); // initialize queue
else
smi.close();
}
SegmentMergeInfo[] match = new SegmentMergeInfo[readers.size()];
while (queue.size() > 0) {
int matchSize = 0; // pop matching terms
match[matchSize++] = (SegmentMergeInfo) queue.pop();
Term term = match[0].term;
SegmentMergeInfo top = (SegmentMergeInfo) queue.top();
while (top != null && term.compareTo(top.term) == 0) {
match[matchSize++] = (SegmentMergeInfo) queue.pop();
top = (SegmentMergeInfo) queue.top();
}
mergeTermInfo(match, matchSize); // add new TermInfo
while (matchSize > 0) {
SegmentMergeInfo smi = match[--matchSize];
if (smi.next())
queue.put(smi); // restore queue
else
smi.close(); // done with a segment
}
}
}
private final TermInfo termInfo = new TermInfo(); // minimize consing
/** Merge one term found in one or more segments. The array <code>smis</code>
* contains segments that are positioned at the same term. <code>N</code>
* is the number of cells in the array actually occupied.
*
* @param smis array of segments
* @param n number of cells in the array actually occupied
*/
private final void mergeTermInfo(SegmentMergeInfo[] smis, int n)
throws IOException {
long freqPointer = freqOutput.getFilePointer();
long proxPointer = proxOutput.getFilePointer();
int df = appendPostings(smis, n); // append posting data
long skipPointer = writeSkip();
if (df > 0) {
// add an entry to the dictionary with pointers to prox and freq files
termInfo.set(df, freqPointer, proxPointer, (int) (skipPointer - freqPointer));
termInfosWriter.add(smis[0].term, termInfo);
}
}
/** Process postings from multiple segments all positioned on the
* same term. Writes out merged entries into freqOutput and
* the proxOutput streams.
*
* @param smis array of segments
* @param n number of cells in the array actually occupied
* @return number of documents across all segments where this term was found
*/
private final int appendPostings(SegmentMergeInfo[] smis, int n)
throws IOException {
int lastDoc = 0;
int df = 0; // number of docs w/ term
resetSkip();
for (int i = 0; i < n; i++) {
SegmentMergeInfo smi = smis[i];
TermPositions postings = smi.getPositions();
int base = smi.base;
int[] docMap = smi.getDocMap();
postings.seek(smi.termEnum);
while (postings.next()) {
int doc = postings.doc();
if (docMap != null)
doc = docMap[doc]; // map around deletions
doc += base; // convert to merged space
if (doc < 0 || (df > 0 && doc <= lastDoc))
throw new IllegalStateException("docs out of order (" + doc +
" <= " + lastDoc + " )");
df++;
if ((df % skipInterval) == 0) {
bufferSkip(lastDoc);
}
int docCode = (doc - lastDoc) << 1; // use low bit to flag freq=1
lastDoc = doc;
int freq = postings.freq();
if (freq == 1) {
freqOutput.writeVInt(docCode | 1); // write doc & freq=1
} else {
freqOutput.writeVInt(docCode); // write doc
freqOutput.writeVInt(freq); // write frequency in doc
}
int lastPosition = 0; // write position deltas
for (int j = 0; j < freq; j++) {
int position = postings.nextPosition();
proxOutput.writeVInt(position - lastPosition);
lastPosition = position;
}
}
}
return df;
}
private RAMOutputStream skipBuffer = new RAMOutputStream();
private int lastSkipDoc;
private long lastSkipFreqPointer;
private long lastSkipProxPointer;
private void resetSkip() {
skipBuffer.reset();
lastSkipDoc = 0;
lastSkipFreqPointer = freqOutput.getFilePointer();
lastSkipProxPointer = proxOutput.getFilePointer();
}
private void bufferSkip(int doc) throws IOException {
long freqPointer = freqOutput.getFilePointer();
long proxPointer = proxOutput.getFilePointer();
skipBuffer.writeVInt(doc - lastSkipDoc);
skipBuffer.writeVInt((int) (freqPointer - lastSkipFreqPointer));
skipBuffer.writeVInt((int) (proxPointer - lastSkipProxPointer));
lastSkipDoc = doc;
lastSkipFreqPointer = freqPointer;
lastSkipProxPointer = proxPointer;
}
private long writeSkip() throws IOException {
long skipPointer = freqOutput.getFilePointer();
skipBuffer.writeTo(freqOutput);
return skipPointer;
}
private void mergeNorms() throws IOException {
byte[] normBuffer = null;
IndexOutput output = null;
try {
for (int i = 0; i < fieldInfos.size(); i++) {
FieldInfo fi = fieldInfos.fieldInfo(i);
if (fi.isIndexed && !fi.omitNorms) {
if (output == null) {
output = directory.createOutput(segment + "." + IndexFileNames.NORMS_EXTENSION);
output.writeBytes(NORMS_HEADER,NORMS_HEADER.length);
}
for (int j = 0; j < readers.size(); j++) {
IndexReader reader = (IndexReader) readers.elementAt(j);
int maxDoc = reader.maxDoc();
if (normBuffer == null || normBuffer.length < maxDoc) {
// the buffer is too small for the current segment
normBuffer = new byte[maxDoc];
}
reader.norms(fi.name, normBuffer, 0);
if (!reader.hasDeletions()) {
//optimized case for segments without deleted docs
output.writeBytes(normBuffer, maxDoc);
} else {
// this segment has deleted docs, so we have to
// check for every doc if it is deleted or not
for (int k = 0; k < maxDoc; k++) {
if (!reader.isDeleted(k)) {
output.writeByte(normBuffer[k]);
}
}
}
}
}
}
} finally {
if (output != null) {
output.close();
}
}
}
}
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