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Apache Lucene (module: highlighter)
/*
* 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.
*/
package org.apache.lucene.search.highlight;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.lucene.analysis.CachingTokenFilter;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.index.BinaryDocValues;
import org.apache.lucene.index.FieldInfos;
import org.apache.lucene.index.FilterLeafReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.LeafReader;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.index.NumericDocValues;
import org.apache.lucene.index.SortedDocValues;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.Terms;
import org.apache.lucene.index.memory.MemoryIndex;
import org.apache.lucene.queries.CommonTermsQuery;
import org.apache.lucene.queries.function.FunctionScoreQuery;
import org.apache.lucene.queries.spans.FieldMaskingSpanQuery;
import org.apache.lucene.queries.spans.SpanFirstQuery;
import org.apache.lucene.queries.spans.SpanNearQuery;
import org.apache.lucene.queries.spans.SpanNotQuery;
import org.apache.lucene.queries.spans.SpanOrQuery;
import org.apache.lucene.queries.spans.SpanQuery;
import org.apache.lucene.queries.spans.SpanTermQuery;
import org.apache.lucene.queries.spans.SpanWeight;
import org.apache.lucene.queries.spans.Spans;
import org.apache.lucene.search.BooleanClause;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.BoostQuery;
import org.apache.lucene.search.ConstantScoreQuery;
import org.apache.lucene.search.DisjunctionMaxQuery;
import org.apache.lucene.search.FieldExistsQuery;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.MatchAllDocsQuery;
import org.apache.lucene.search.MultiPhraseQuery;
import org.apache.lucene.search.MultiTermQuery;
import org.apache.lucene.search.PhraseQuery;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.QueryVisitor;
import org.apache.lucene.search.ScoreMode;
import org.apache.lucene.search.SynonymQuery;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.util.Bits;
import org.apache.lucene.util.IOUtils;
/**
* Class used to extract {@link WeightedSpanTerm}s from a {@link Query} based on whether {@link
* Term}s from the {@link Query} are contained in a supplied {@link TokenStream}.
*
* In order to support additional, by default unsupported queries, subclasses can override {@link
* #extract(Query, float, Map)} for extracting wrapped or delegate queries and {@link
* #extractUnknownQuery(Query, Map)} to process custom leaf queries:
*
*
*
* WeightedSpanTermExtractor extractor = new WeightedSpanTermExtractor() {
* protected void extract(Query query, float boost, Map<String, WeightedSpanTerm>terms) throws IOException {
* if (query instanceof QueryWrapper) {
* extract(((QueryWrapper)query).getQuery(), boost, terms);
* } else {
* super.extract(query, boost, terms);
* }
* }
*
* protected void extractUnknownQuery(Query query, Map<String, WeightedSpanTerm> terms) throws IOException {
* if (query instanceOf CustomTermQuery) {
* Term term = ((CustomTermQuery) query).getTerm();
* terms.put(term.field(), new WeightedSpanTerm(1, term.text()));
* }
* }
* };
* }
*
*
*/
public class WeightedSpanTermExtractor {
private String fieldName;
private TokenStream tokenStream; // set subsequent to getWeightedSpanTerms* methods
private String defaultField;
private boolean expandMultiTermQuery;
private boolean cachedTokenStream;
private boolean wrapToCaching = true;
private int maxDocCharsToAnalyze;
private boolean usePayloads = false;
private LeafReader internalReader = null;
public WeightedSpanTermExtractor() {
this(null);
}
public WeightedSpanTermExtractor(String defaultField) {
this.defaultField = defaultField;
}
/**
* Fills a Map with {@link WeightedSpanTerm}s using the terms from the supplied
* Query.
*
* @param query Query to extract Terms from
* @param terms Map to place created WeightedSpanTerms in
* @throws IOException If there is a low-level I/O error
*/
protected void extract(Query query, float boost, Map terms)
throws IOException {
if (query instanceof BoostQuery) {
BoostQuery boostQuery = (BoostQuery) query;
extract(boostQuery.getQuery(), boost * boostQuery.getBoost(), terms);
} else if (query instanceof BooleanQuery) {
for (BooleanClause clause : (BooleanQuery) query) {
if (!clause.isProhibited()) {
extract(clause.getQuery(), boost, terms);
}
}
} else if (query instanceof PhraseQuery) {
PhraseQuery phraseQuery = ((PhraseQuery) query);
Term[] phraseQueryTerms = phraseQuery.getTerms();
if (phraseQueryTerms.length == 1) {
extractWeightedSpanTerms(terms, new SpanTermQuery(phraseQueryTerms[0]), boost);
} else {
SpanQuery[] clauses = new SpanQuery[phraseQueryTerms.length];
for (int i = 0; i < phraseQueryTerms.length; i++) {
clauses[i] = new SpanTermQuery(phraseQueryTerms[i]);
}
// sum position increments beyond 1
int positionGaps = 0;
int[] positions = phraseQuery.getPositions();
if (positions.length >= 2) {
// positions are in increasing order. max(0,...) is just a safeguard.
positionGaps =
Math.max(0, positions[positions.length - 1] - positions[0] - positions.length + 1);
}
// if original slop is 0 then require inOrder
boolean inorder = (phraseQuery.getSlop() == 0);
SpanNearQuery sp =
new SpanNearQuery(clauses, phraseQuery.getSlop() + positionGaps, inorder);
extractWeightedSpanTerms(terms, sp, boost);
}
} else if (query instanceof TermQuery || query instanceof SynonymQuery) {
extractWeightedTerms(terms, query, boost);
} else if (query instanceof SpanQuery) {
extractWeightedSpanTerms(terms, (SpanQuery) query, boost);
} else if (query instanceof ConstantScoreQuery) {
final Query q = ((ConstantScoreQuery) query).getQuery();
if (q != null) {
extract(q, boost, terms);
}
} else if (query instanceof CommonTermsQuery) {
// specialized since rewriting would change the result query
// this query is index sensitive.
extractWeightedTerms(terms, query, boost);
} else if (query instanceof DisjunctionMaxQuery) {
for (Query clause : ((DisjunctionMaxQuery) query)) {
extract(clause, boost, terms);
}
} else if (query instanceof MultiPhraseQuery) {
final MultiPhraseQuery mpq = (MultiPhraseQuery) query;
final Term[][] termArrays = mpq.getTermArrays();
final int[] positions = mpq.getPositions();
if (positions.length > 0) {
int maxPosition = positions[positions.length - 1];
for (int i = 0; i < positions.length - 1; ++i) {
if (positions[i] > maxPosition) {
maxPosition = positions[i];
}
}
@SuppressWarnings({"unchecked", "rawtypes"})
final List[] disjunctLists = new List[maxPosition + 1];
int distinctPositions = 0;
for (int i = 0; i < termArrays.length; ++i) {
final Term[] termArray = termArrays[i];
List disjuncts = disjunctLists[positions[i]];
if (disjuncts == null) {
disjuncts = (disjunctLists[positions[i]] = new ArrayList<>(termArray.length));
++distinctPositions;
}
for (Term aTermArray : termArray) {
disjuncts.add(new SpanTermQuery(aTermArray));
}
}
int positionGaps = 0;
int position = 0;
final SpanQuery[] clauses = new SpanQuery[distinctPositions];
for (List disjuncts : disjunctLists) {
if (disjuncts != null) {
clauses[position++] =
new SpanOrQuery(disjuncts.toArray(new SpanQuery[disjuncts.size()]));
} else {
++positionGaps;
}
}
if (clauses.length == 1) {
extractWeightedSpanTerms(terms, clauses[0], boost);
} else {
final int slop = mpq.getSlop();
final boolean inorder = (slop == 0);
SpanNearQuery sp = new SpanNearQuery(clauses, slop + positionGaps, inorder);
extractWeightedSpanTerms(terms, sp, boost);
}
}
} else if (query instanceof MatchAllDocsQuery) {
// nothing
} else if (query instanceof FieldExistsQuery) {
// nothing
} else if (query instanceof FunctionScoreQuery) {
extract(((FunctionScoreQuery) query).getWrappedQuery(), boost, terms);
} else if (isQueryUnsupported(query.getClass())) {
// nothing
} else {
if (query instanceof MultiTermQuery
&& (!expandMultiTermQuery || !fieldNameComparator(((MultiTermQuery) query).getField()))) {
return;
}
Query origQuery = query;
final IndexReader reader = getLeafContext().reader();
Query rewritten;
if (query instanceof MultiTermQuery) {
rewritten = MultiTermQuery.SCORING_BOOLEAN_REWRITE.rewrite(reader, (MultiTermQuery) query);
} else {
rewritten = origQuery.rewrite(new IndexSearcher(reader));
}
if (rewritten != origQuery) {
// only rewrite once and then flatten again - the rewritten query could have a special
// treatment
// if this method is overwritten in a subclass or above in the next recursion
extract(rewritten, boost, terms);
} else {
extractUnknownQuery(query, terms);
}
}
}
protected boolean isQueryUnsupported(Class clazz) {
// spatial queries do not support highlighting:
if (clazz.getName().startsWith("org.apache.lucene.spatial.")) {
return true;
}
// spatial3d queries are also not supported:
if (clazz.getName().startsWith("org.apache.lucene.spatial3d.")) {
return true;
}
return false;
}
protected void extractUnknownQuery(Query query, Map terms)
throws IOException {
// for sub-classing to extract custom queries
}
/**
* Fills a Map with {@link WeightedSpanTerm}s using the terms from the supplied
* SpanQuery.
*
* @param terms Map to place created WeightedSpanTerms in
* @param spanQuery SpanQuery to extract Terms from
* @throws IOException If there is a low-level I/O error
*/
protected void extractWeightedSpanTerms(
Map terms, SpanQuery spanQuery, float boost) throws IOException {
Set fieldNames;
if (fieldName == null) {
fieldNames = new HashSet<>();
collectSpanQueryFields(spanQuery, fieldNames);
} else {
fieldNames = new HashSet<>(1);
fieldNames.add(fieldName);
}
// To support the use of the default field name
if (defaultField != null) {
fieldNames.add(defaultField);
}
Map queries = new HashMap<>();
Set nonWeightedTerms = new HashSet<>();
final boolean mustRewriteQuery = mustRewriteQuery(spanQuery);
final IndexSearcher searcher = new IndexSearcher(getLeafContext());
searcher.setQueryCache(null);
if (mustRewriteQuery) {
final SpanQuery rewrittenQuery = (SpanQuery) searcher.rewrite(spanQuery);
for (final String field : fieldNames) {
queries.put(field, rewrittenQuery);
}
rewrittenQuery.visit(QueryVisitor.termCollector(nonWeightedTerms));
} else {
spanQuery.visit(QueryVisitor.termCollector(nonWeightedTerms));
}
List spanPositions = new ArrayList<>();
for (final String field : fieldNames) {
final SpanQuery q;
if (mustRewriteQuery) {
q = queries.get(field);
} else {
q = spanQuery;
}
LeafReaderContext context = getLeafContext();
SpanWeight w =
(SpanWeight) searcher.createWeight(searcher.rewrite(q), ScoreMode.COMPLETE_NO_SCORES, 1);
Bits acceptDocs = context.reader().getLiveDocs();
final Spans spans = w.getSpans(context, SpanWeight.Postings.POSITIONS);
if (spans == null) {
return;
}
// collect span positions
while (spans.nextDoc() != Spans.NO_MORE_DOCS) {
if (acceptDocs != null && acceptDocs.get(spans.docID()) == false) {
continue;
}
while (spans.nextStartPosition() != Spans.NO_MORE_POSITIONS) {
spanPositions.add(new PositionSpan(spans.startPosition(), spans.endPosition() - 1));
}
}
}
if (spanPositions.size() == 0) {
// no spans found
return;
}
for (final Term queryTerm : nonWeightedTerms) {
if (fieldNameComparator(queryTerm.field())) {
WeightedSpanTerm weightedSpanTerm = terms.get(queryTerm.text());
if (weightedSpanTerm == null) {
weightedSpanTerm = new WeightedSpanTerm(boost, queryTerm.text());
weightedSpanTerm.addPositionSpans(spanPositions);
weightedSpanTerm.positionSensitive = true;
terms.put(queryTerm.text(), weightedSpanTerm);
} else {
if (spanPositions.size() > 0) {
weightedSpanTerm.addPositionSpans(spanPositions);
}
}
}
}
}
/**
* Fills a Map with {@link WeightedSpanTerm}s using the terms from the supplied
* Query.
*
* @param terms Map to place created WeightedSpanTerms in
* @param query Query to extract Terms from
* @throws IOException If there is a low-level I/O error
*/
protected void extractWeightedTerms(Map terms, Query query, float boost)
throws IOException {
Set nonWeightedTerms = new HashSet<>();
final IndexSearcher searcher = new IndexSearcher(getLeafContext());
searcher.rewrite(query).visit(QueryVisitor.termCollector(nonWeightedTerms));
for (final Term queryTerm : nonWeightedTerms) {
if (fieldNameComparator(queryTerm.field())) {
WeightedSpanTerm weightedSpanTerm = new WeightedSpanTerm(boost, queryTerm.text());
terms.put(queryTerm.text(), weightedSpanTerm);
}
}
}
/** Necessary to implement matches for queries against defaultField */
protected boolean fieldNameComparator(String fieldNameToCheck) {
boolean rv =
fieldName == null
|| fieldName.equals(fieldNameToCheck)
|| (defaultField != null && defaultField.equals(fieldNameToCheck));
return rv;
}
protected LeafReaderContext getLeafContext() throws IOException {
if (internalReader == null) {
boolean cacheIt = wrapToCaching && !(tokenStream instanceof CachingTokenFilter);
// If it's from term vectors, simply wrap the underlying Terms in a reader
if (tokenStream instanceof TokenStreamFromTermVector) {
cacheIt = false;
Terms termVectorTerms = ((TokenStreamFromTermVector) tokenStream).getTermVectorTerms();
if (termVectorTerms.hasPositions() && termVectorTerms.hasOffsets()) {
internalReader =
new TermVectorLeafReader(DelegatingLeafReader.FIELD_NAME, termVectorTerms);
}
}
// Use MemoryIndex (index/invert this tokenStream now)
if (internalReader == null) {
final MemoryIndex indexer = new MemoryIndex(true, usePayloads); // offsets and payloads
if (cacheIt) {
assert !cachedTokenStream;
tokenStream =
new CachingTokenFilter(new OffsetLimitTokenFilter(tokenStream, maxDocCharsToAnalyze));
cachedTokenStream = true;
indexer.addField(DelegatingLeafReader.FIELD_NAME, tokenStream);
} else {
indexer.addField(
DelegatingLeafReader.FIELD_NAME,
new OffsetLimitTokenFilter(tokenStream, maxDocCharsToAnalyze));
}
final IndexSearcher searcher = indexer.createSearcher();
// MEM index has only atomic ctx
internalReader = ((LeafReaderContext) searcher.getTopReaderContext()).reader();
}
// Now wrap it so we always use a common field.
this.internalReader = new DelegatingLeafReader(internalReader);
}
return internalReader.getContext();
}
/*
* This reader will just delegate every call to a single field in the wrapped
* LeafReader. This way we only need to build this field once rather than
* N-Times
*/
static final class DelegatingLeafReader extends FilterLeafReader {
private static final String FIELD_NAME = "shadowed_field";
DelegatingLeafReader(LeafReader in) {
super(in);
}
@Override
public FieldInfos getFieldInfos() {
throw new UnsupportedOperationException(); // TODO merge them
}
@Override
public Terms terms(String field) throws IOException {
return super.terms(DelegatingLeafReader.FIELD_NAME);
}
@Override
public NumericDocValues getNumericDocValues(String field) throws IOException {
return super.getNumericDocValues(FIELD_NAME);
}
@Override
public BinaryDocValues getBinaryDocValues(String field) throws IOException {
return super.getBinaryDocValues(FIELD_NAME);
}
@Override
public SortedDocValues getSortedDocValues(String field) throws IOException {
return super.getSortedDocValues(FIELD_NAME);
}
@Override
public NumericDocValues getNormValues(String field) throws IOException {
return super.getNormValues(FIELD_NAME);
}
@Override
public CacheHelper getCoreCacheHelper() {
return null;
}
@Override
public CacheHelper getReaderCacheHelper() {
return null;
}
}
/**
* Creates a Map of WeightedSpanTerms from the given Query and
* TokenStream.
*
* @param query that caused hit
* @param tokenStream of text to be highlighted
* @return Map containing WeightedSpanTerms
* @throws IOException If there is a low-level I/O error
*/
public Map getWeightedSpanTerms(
Query query, float boost, TokenStream tokenStream) throws IOException {
return getWeightedSpanTerms(query, boost, tokenStream, null);
}
/**
* Creates a Map of WeightedSpanTerms from the given Query and
* TokenStream.
*
* @param query that caused hit
* @param tokenStream of text to be highlighted
* @param fieldName restricts Term's used based on field name
* @return Map containing WeightedSpanTerms
* @throws IOException If there is a low-level I/O error
*/
public Map getWeightedSpanTerms(
Query query, float boost, TokenStream tokenStream, String fieldName) throws IOException {
this.fieldName = fieldName;
Map terms = new PositionCheckingMap<>();
this.tokenStream = tokenStream;
try {
extract(query, boost, terms);
} finally {
IOUtils.close(internalReader);
}
return terms;
}
/**
* Creates a Map of WeightedSpanTerms from the given Query and
* TokenStream. Uses a supplied IndexReader to properly weight terms (for
* gradient highlighting).
*
* @param query that caused hit
* @param tokenStream of text to be highlighted
* @param fieldName restricts Term's used based on field name
* @param reader to use for scoring
* @return Map of WeightedSpanTerms with quasi tf/idf scores
* @throws IOException If there is a low-level I/O error
*/
public Map getWeightedSpanTermsWithScores(
Query query, float boost, TokenStream tokenStream, String fieldName, IndexReader reader)
throws IOException {
if (fieldName != null) {
this.fieldName = fieldName;
} else {
this.fieldName = null;
}
this.tokenStream = tokenStream;
Map terms = new PositionCheckingMap<>();
extract(query, boost, terms);
int totalNumDocs = reader.maxDoc();
Set weightedTerms = terms.keySet();
Iterator it = weightedTerms.iterator();
try {
while (it.hasNext()) {
WeightedSpanTerm weightedSpanTerm = terms.get(it.next());
int docFreq = reader.docFreq(new Term(fieldName, weightedSpanTerm.term));
// IDF algorithm taken from ClassicSimilarity class
float idf = (float) (Math.log(totalNumDocs / (double) (docFreq + 1)) + 1.0);
weightedSpanTerm.weight *= idf;
}
} finally {
IOUtils.close(internalReader);
}
return terms;
}
protected void collectSpanQueryFields(SpanQuery spanQuery, Set fieldNames) {
if (spanQuery instanceof FieldMaskingSpanQuery) {
collectSpanQueryFields(((FieldMaskingSpanQuery) spanQuery).getMaskedQuery(), fieldNames);
} else if (spanQuery instanceof SpanFirstQuery) {
collectSpanQueryFields(((SpanFirstQuery) spanQuery).getMatch(), fieldNames);
} else if (spanQuery instanceof SpanNearQuery) {
for (final SpanQuery clause : ((SpanNearQuery) spanQuery).getClauses()) {
collectSpanQueryFields(clause, fieldNames);
}
} else if (spanQuery instanceof SpanNotQuery) {
collectSpanQueryFields(((SpanNotQuery) spanQuery).getInclude(), fieldNames);
} else if (spanQuery instanceof SpanOrQuery) {
for (final SpanQuery clause : ((SpanOrQuery) spanQuery).getClauses()) {
collectSpanQueryFields(clause, fieldNames);
}
} else {
fieldNames.add(spanQuery.getField());
}
}
protected boolean mustRewriteQuery(SpanQuery spanQuery) {
if (!expandMultiTermQuery) {
return false; // Will throw UnsupportedOperationException in case of a SpanRegexQuery.
} else if (spanQuery instanceof FieldMaskingSpanQuery) {
return mustRewriteQuery(((FieldMaskingSpanQuery) spanQuery).getMaskedQuery());
} else if (spanQuery instanceof SpanFirstQuery) {
return mustRewriteQuery(((SpanFirstQuery) spanQuery).getMatch());
} else if (spanQuery instanceof SpanNearQuery) {
for (final SpanQuery clause : ((SpanNearQuery) spanQuery).getClauses()) {
if (mustRewriteQuery(clause)) {
return true;
}
}
return false;
} else if (spanQuery instanceof SpanNotQuery) {
SpanNotQuery spanNotQuery = (SpanNotQuery) spanQuery;
return mustRewriteQuery(spanNotQuery.getInclude())
|| mustRewriteQuery(spanNotQuery.getExclude());
} else if (spanQuery instanceof SpanOrQuery) {
for (final SpanQuery clause : ((SpanOrQuery) spanQuery).getClauses()) {
if (mustRewriteQuery(clause)) {
return true;
}
}
return false;
} else if (spanQuery instanceof SpanTermQuery) {
return false;
} else {
return true;
}
}
/**
* This class makes sure that if both position sensitive and insensitive versions of the same term
* are added, the position insensitive one wins.
*/
@SuppressWarnings("serial")
protected static class PositionCheckingMap extends HashMap {
@Override
public void putAll(Map m) {
for (Map.Entry entry : m.entrySet())
this.put(entry.getKey(), entry.getValue());
}
@Override
public WeightedSpanTerm put(K key, WeightedSpanTerm value) {
WeightedSpanTerm prev = super.put(key, value);
if (prev == null) return prev;
WeightedSpanTerm prevTerm = prev;
WeightedSpanTerm newTerm = value;
if (!prevTerm.positionSensitive) {
newTerm.positionSensitive = false;
}
return prev;
}
}
public boolean getExpandMultiTermQuery() {
return expandMultiTermQuery;
}
public void setExpandMultiTermQuery(boolean expandMultiTermQuery) {
this.expandMultiTermQuery = expandMultiTermQuery;
}
public boolean isUsePayloads() {
return usePayloads;
}
public void setUsePayloads(boolean usePayloads) {
this.usePayloads = usePayloads;
}
public boolean isCachedTokenStream() {
return cachedTokenStream;
}
/**
* Returns the tokenStream which may have been wrapped in a CachingTokenFilter.
* getWeightedSpanTerms* sets the tokenStream, so don't call this before.
*/
public TokenStream getTokenStream() {
assert tokenStream != null;
return tokenStream;
}
/**
* By default, {@link TokenStream}s that are not of the type {@link CachingTokenFilter} are
* wrapped in a {@link CachingTokenFilter} to ensure an efficient reset - if you are already using
* a different caching {@link TokenStream} impl and you don't want it to be wrapped, set this to
* false. This setting is ignored when a term vector based TokenStream is supplied, since it can
* be reset efficiently.
*/
public void setWrapIfNotCachingTokenFilter(boolean wrap) {
this.wrapToCaching = wrap;
}
/**
* A threshold of number of characters to analyze. When a TokenStream based on term vectors with
* offsets and positions are supplied, this setting does not apply.
*/
protected final void setMaxDocCharsToAnalyze(int maxDocCharsToAnalyze) {
this.maxDocCharsToAnalyze = maxDocCharsToAnalyze;
}
}