package org.apache.lucene.search.highlight;
/**
* 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.ArrayList;
import java.util.Collection;
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.FilterIndexReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermEnum;
import org.apache.lucene.index.memory.MemoryIndex;
import org.apache.lucene.search.BooleanClause;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.ConstantScoreRangeQuery;
import org.apache.lucene.search.DisjunctionMaxQuery;
import org.apache.lucene.search.FilteredQuery;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.MultiPhraseQuery;
import org.apache.lucene.search.PhraseQuery;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.search.spans.SpanNearQuery;
import org.apache.lucene.search.spans.SpanOrQuery;
import org.apache.lucene.search.spans.SpanQuery;
import org.apache.lucene.search.spans.SpanTermQuery;
import org.apache.lucene.search.spans.Spans;
/**
* Class used to extract {@link WeightedSpanTerm}s from a {@link Query} based on whether Terms from the query are contained in a supplied TokenStream.
*/
public class WeightedSpanTermExtractor {
private String fieldName;
private CachingTokenFilter cachedTokenFilter;
private Map readers = new HashMap(10); // Map<String, IndexReader>
private String defaultField;
private boolean highlightCnstScrRngQuery;
public WeightedSpanTermExtractor() {
}
public WeightedSpanTermExtractor(String defaultField) {
if (defaultField != null) {
this.defaultField = defaultField.intern();
}
}
private void closeReaders() {
Collection readerSet = readers.values();
Iterator it = readerSet.iterator();
while (it.hasNext()) {
IndexReader reader = (IndexReader) it.next();
try {
reader.close();
} catch (IOException e) {
// alert?
}
}
}
/**
* Fills a <code>Map</code> with <@link WeightedSpanTerm>s using the terms from the supplied <code>Query</code>.
*
* @param query
* Query to extract Terms from
* @param terms
* Map to place created WeightedSpanTerms in
* @throws IOException
*/
private void extract(Query query, Map terms) throws IOException {
if (query instanceof BooleanQuery) {
BooleanClause[] queryClauses = ((BooleanQuery) query).getClauses();
Map booleanTerms = new PositionCheckingMap();
for (int i = 0; i < queryClauses.length; i++) {
if (!queryClauses[i].isProhibited()) {
extract(queryClauses[i].getQuery(), booleanTerms);
}
}
terms.putAll(booleanTerms);
} else if (query instanceof PhraseQuery) {
Term[] phraseQueryTerms = ((PhraseQuery) query).getTerms();
SpanQuery[] clauses = new SpanQuery[phraseQueryTerms.length];
for (int i = 0; i < phraseQueryTerms.length; i++) {
clauses[i] = new SpanTermQuery(phraseQueryTerms[i]);
}
int slop = ((PhraseQuery) query).getSlop();
boolean inorder = false;
if (slop == 0) {
inorder = true;
}
SpanNearQuery sp = new SpanNearQuery(clauses, slop, inorder);
sp.setBoost(query.getBoost());
extractWeightedSpanTerms(terms, sp);
} else if (query instanceof TermQuery) {
extractWeightedTerms(terms, query);
} else if (query instanceof SpanQuery) {
extractWeightedSpanTerms(terms, (SpanQuery) query);
} else if (query instanceof FilteredQuery) {
extract(((FilteredQuery) query).getQuery(), terms);
} else if (query instanceof DisjunctionMaxQuery) {
Map disjunctTerms = new PositionCheckingMap();
for (Iterator iterator = ((DisjunctionMaxQuery) query).iterator(); iterator.hasNext();) {
extract((Query) iterator.next(), disjunctTerms);
}
terms.putAll(disjunctTerms);
} else if (query instanceof MultiPhraseQuery) {
final MultiPhraseQuery mpq = (MultiPhraseQuery) query;
final List 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];
}
}
final List[] disjunctLists = new List[maxPosition + 1];
int distinctPositions = 0;
for (int i = 0; i < termArrays.size(); ++i) {
final Term[] termArray = (Term[]) termArrays.get(i);
List disjuncts = disjunctLists[positions[i]];
if (disjuncts == null) {
disjuncts = (disjunctLists[positions[i]] = new ArrayList(termArray.length));
++distinctPositions;
}
for (int j = 0; j < termArray.length; ++j) {
disjuncts.add(new SpanTermQuery(termArray[j]));
}
}
int positionGaps = 0;
int position = 0;
final SpanQuery[] clauses = new SpanQuery[distinctPositions];
for (int i = 0; i < disjunctLists.length; ++i) {
List disjuncts = disjunctLists[i];
if (disjuncts != null) {
clauses[position++] = new SpanOrQuery((SpanQuery[]) disjuncts
.toArray(new SpanQuery[disjuncts.size()]));
} else {
++positionGaps;
}
}
final int slop = mpq.getSlop();
final boolean inorder = (slop == 0);
SpanNearQuery sp = new SpanNearQuery(clauses, slop + positionGaps, inorder);
sp.setBoost(query.getBoost());
extractWeightedSpanTerms(terms, sp);
}
} else if (highlightCnstScrRngQuery && query instanceof ConstantScoreRangeQuery) {
ConstantScoreRangeQuery q = (ConstantScoreRangeQuery) query;
Term lower = new Term(fieldName, q.getLowerVal());
Term upper = new Term(fieldName, q.getUpperVal());
FilterIndexReader fir = new FilterIndexReader(getReaderForField(fieldName));
try {
TermEnum te = fir.terms(lower);
BooleanQuery bq = new BooleanQuery();
do {
Term term = te.term();
if (term != null && upper.compareTo(term) >= 0) {
bq.add(new BooleanClause(new TermQuery(term), BooleanClause.Occur.SHOULD));
} else {
break;
}
} while (te.next());
extract(bq, terms);
} finally {
fir.close();
}
}
}
/**
* Fills a <code>Map</code> with <@link WeightedSpanTerm>s using the terms from the supplied <code>SpanQuery</code>.
*
* @param terms
* Map to place created WeightedSpanTerms in
* @param spanQuery
* SpanQuery to extract Terms from
* @throws IOException
*/
private void extractWeightedSpanTerms(Map terms, SpanQuery spanQuery) throws IOException {
Set nonWeightedTerms = new HashSet();
spanQuery.extractTerms(nonWeightedTerms);
Set fieldNames;
if (fieldName == null) {
fieldNames = new HashSet();
for (Iterator iter = nonWeightedTerms.iterator(); iter.hasNext();) {
Term queryTerm = (Term) iter.next();
fieldNames.add(queryTerm.field());
}
} else {
fieldNames = new HashSet(1);
fieldNames.add(fieldName);
}
// To support the use of the default field name
if (defaultField != null) {
fieldNames.add(defaultField);
}
Iterator it = fieldNames.iterator();
List spanPositions = new ArrayList();
while (it.hasNext()) {
String field = (String) it.next();
IndexReader reader = getReaderForField(field);
Spans spans = spanQuery.getSpans(reader);
// collect span positions
while (spans.next()) {
spanPositions.add(new PositionSpan(spans.start(), spans.end() - 1));
}
cachedTokenFilter.reset();
}
if (spanPositions.size() == 0) {
// no spans found
return;
}
for (Iterator iter = nonWeightedTerms.iterator(); iter.hasNext();) {
Term queryTerm = (Term) iter.next();
if (fieldNameComparator(queryTerm.field())) {
WeightedSpanTerm weightedSpanTerm = (WeightedSpanTerm) terms.get(queryTerm.text());
if (weightedSpanTerm == null) {
weightedSpanTerm = new WeightedSpanTerm(spanQuery.getBoost(), queryTerm.text());
weightedSpanTerm.addPositionSpans(spanPositions);
weightedSpanTerm.positionSensitive = true;
terms.put(queryTerm.text(), weightedSpanTerm);
} else {
if (spanPositions.size() > 0) {
weightedSpanTerm.addPositionSpans(spanPositions);
}
}
}
}
}
/**
* Fills a <code>Map</code> with <@link WeightedSpanTerm>s using the terms from the supplied <code>Query</code>.
*
* @param terms
* Map to place created WeightedSpanTerms in
* @param query
* Query to extract Terms from
* @throws IOException
*/
private void extractWeightedTerms(Map terms, Query query) throws IOException {
Set nonWeightedTerms = new HashSet();
query.extractTerms(nonWeightedTerms);
for (Iterator iter = nonWeightedTerms.iterator(); iter.hasNext();) {
Term queryTerm = (Term) iter.next();
if (fieldNameComparator(queryTerm.field())) {
WeightedSpanTerm weightedSpanTerm = new WeightedSpanTerm(query.getBoost(), queryTerm.text());
terms.put(queryTerm.text(), weightedSpanTerm);
}
}
}
/**
* Necessary to implement matches for queries against <code>defaultField</code>
*/
private boolean fieldNameComparator(String fieldNameToCheck) {
boolean rv = fieldName == null || fieldNameToCheck == fieldName
|| fieldNameToCheck == defaultField;
return rv;
}
private IndexReader getReaderForField(String field) {
IndexReader reader = (IndexReader) readers.get(field);
if (reader == null) {
MemoryIndex indexer = new MemoryIndex();
indexer.addField(field, cachedTokenFilter);
IndexSearcher searcher = indexer.createSearcher();
reader = searcher.getIndexReader();
readers.put(field, reader);
}
return reader;
}
/**
* Creates a Map of <code>WeightedSpanTerms</code> from the given <code>Query</code> and <code>TokenStream</code>.
*
* <p>
*
* @param query
* that caused hit
* @param tokenStream
* of text to be highlighted
* @return
* @throws IOException
*/
public Map getWeightedSpanTerms(Query query, CachingTokenFilter cachingTokenFilter)
throws IOException {
this.fieldName = null;
this.cachedTokenFilter = cachingTokenFilter;
Map terms = new PositionCheckingMap();
try {
extract(query, terms);
} finally {
closeReaders();
}
return terms;
}
/**
* Creates a Map of <code>WeightedSpanTerms</code> from the given <code>Query</code> and <code>TokenStream</code>.
*
* <p>
*
* @param query
* that caused hit
* @param tokenStream
* of text to be highlighted
* @param fieldName
* restricts Term's used based on field name
* @return
* @throws IOException
*/
public Map getWeightedSpanTerms(Query query, CachingTokenFilter cachingTokenFilter,
String fieldName) throws IOException {
if (fieldName != null) {
this.fieldName = fieldName.intern();
}
Map terms = new PositionCheckingMap();
this.cachedTokenFilter = cachingTokenFilter;
try {
extract(query, terms);
} finally {
closeReaders();
}
return terms;
}
/**
* Creates a Map of <code>WeightedSpanTerms</code> from the given <code>Query</code> and <code>TokenStream</code>. Uses a supplied
* <code>IndexReader</code> to properly weight terms (for gradient highlighting).
*
* <p>
*
* @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
* @throws IOException
*/
public Map getWeightedSpanTermsWithScores(Query query, TokenStream tokenStream, String fieldName,
IndexReader reader) throws IOException {
this.fieldName = fieldName;
this.cachedTokenFilter = new CachingTokenFilter(tokenStream);
Map terms = new PositionCheckingMap();
extract(query, terms);
int totalNumDocs = reader.numDocs();
Set weightedTerms = terms.keySet();
Iterator it = weightedTerms.iterator();
try {
while (it.hasNext()) {
WeightedSpanTerm weightedSpanTerm = (WeightedSpanTerm) terms.get(it.next());
int docFreq = reader.docFreq(new Term(fieldName, weightedSpanTerm.term));
// docFreq counts deletes
if(totalNumDocs < docFreq) {
docFreq = totalNumDocs;
}
// IDF algorithm taken from DefaultSimilarity class
float idf = (float) (Math.log((float) totalNumDocs / (double) (docFreq + 1)) + 1.0);
weightedSpanTerm.weight *= idf;
}
} finally {
closeReaders();
}
return terms;
}
public boolean isHighlightCnstScrRngQuery() {
return highlightCnstScrRngQuery;
}
public void setHighlightCnstScrRngQuery(boolean highlightCnstScrRngQuery) {
this.highlightCnstScrRngQuery = highlightCnstScrRngQuery;
}
/**
* This class makes sure that if both position sensitive and insensitive
* versions of the same term are added, the position insensitive one wins.
*/
private class PositionCheckingMap extends HashMap {
public void putAll(Map m) {
Iterator it = m.keySet().iterator();
while (it.hasNext()) {
Object key = it.next();
Object val = m.get(key);
this.put(key, val);
}
}
public Object put(Object key, Object value) {
Object prev = super.put(key, value);
if (prev == null) return prev;
WeightedSpanTerm prevTerm = (WeightedSpanTerm)prev;
WeightedSpanTerm newTerm = (WeightedSpanTerm)value;
if (!prevTerm.positionSensitive) {
newTerm.positionSensitive = false;
}
return prev;
}
}
}