| /* |
| * 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; |
| |
| |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Comparator; |
| import java.util.List; |
| |
| import org.apache.lucene.index.LeafReaderContext; |
| import org.apache.lucene.search.TotalHits.Relation; |
| |
| /** |
| * A {@link Rescorer} that re-sorts according to a provided |
| * Sort. |
| */ |
| |
| public class SortRescorer extends Rescorer { |
| |
| private final Sort sort; |
| |
| /** Sole constructor. */ |
| public SortRescorer(Sort sort) { |
| this.sort = sort; |
| } |
| |
| @Override |
| public TopDocs rescore(IndexSearcher searcher, TopDocs firstPassTopDocs, int topN) throws IOException { |
| |
| // Copy ScoreDoc[] and sort by ascending docID: |
| ScoreDoc[] hits = firstPassTopDocs.scoreDocs.clone(); |
| Comparator<ScoreDoc> docIdComparator = Comparator.comparingInt(sd -> sd.doc); |
| Arrays.sort(hits, docIdComparator); |
| |
| List<LeafReaderContext> leaves = searcher.getIndexReader().leaves(); |
| |
| TopFieldCollector collector = TopFieldCollector.create(sort, topN, Integer.MAX_VALUE); |
| |
| // Now merge sort docIDs from hits, with reader's leaves: |
| int hitUpto = 0; |
| int readerUpto = -1; |
| int endDoc = 0; |
| int docBase = 0; |
| |
| LeafCollector leafCollector = null; |
| ScoreAndDoc scoreAndDoc = new ScoreAndDoc(); |
| |
| while (hitUpto < hits.length) { |
| ScoreDoc hit = hits[hitUpto]; |
| int docID = hit.doc; |
| LeafReaderContext readerContext = null; |
| while (docID >= endDoc) { |
| readerUpto++; |
| readerContext = leaves.get(readerUpto); |
| endDoc = readerContext.docBase + readerContext.reader().maxDoc(); |
| } |
| |
| if (readerContext != null) { |
| // We advanced to another segment: |
| leafCollector = collector.getLeafCollector(readerContext); |
| leafCollector.setScorer(scoreAndDoc); |
| docBase = readerContext.docBase; |
| } |
| |
| scoreAndDoc.score = hit.score; |
| scoreAndDoc.doc = docID - docBase; |
| |
| leafCollector.collect(scoreAndDoc.doc); |
| |
| hitUpto++; |
| } |
| |
| TopDocs rescoredDocs = collector.topDocs(); |
| // set scores from the original score docs |
| assert hits.length == rescoredDocs.scoreDocs.length; |
| ScoreDoc[] rescoredDocsClone = rescoredDocs.scoreDocs.clone(); |
| Arrays.sort(rescoredDocsClone, docIdComparator); |
| for (int i = 0; i < rescoredDocsClone.length; ++i) { |
| rescoredDocsClone[i].score = hits[i].score; |
| } |
| return rescoredDocs; |
| } |
| |
| @Override |
| public Explanation explain(IndexSearcher searcher, Explanation firstPassExplanation, int docID) throws IOException { |
| TopDocs oneHit = new TopDocs(new TotalHits(1, Relation.EQUAL_TO), new ScoreDoc[] {new ScoreDoc(docID, firstPassExplanation.getValue().floatValue())}); |
| TopDocs hits = rescore(searcher, oneHit, 1); |
| assert hits.totalHits.value == 1; |
| |
| List<Explanation> subs = new ArrayList<>(); |
| |
| // Add first pass: |
| Explanation first = Explanation.match(firstPassExplanation.getValue(), "first pass score", firstPassExplanation); |
| subs.add(first); |
| |
| FieldDoc fieldDoc = (FieldDoc) hits.scoreDocs[0]; |
| |
| // Add sort values: |
| SortField[] sortFields = sort.getSort(); |
| for(int i=0;i<sortFields.length;i++) { |
| subs.add(Explanation.match(0.0f, "sort field " + sortFields[i].toString() + " value=" + fieldDoc.fields[i])); |
| } |
| |
| // TODO: if we could ask the Sort to explain itself then |
| // we wouldn't need the separate ExpressionRescorer... |
| return Explanation.match(0.0f, "sort field values for sort=" + sort.toString(), subs); |
| } |
| } |