package org.apache.lucene.search; /** * 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 org.apache.lucene.index.IndexReader; import org.apache.lucene.search.FieldValueHitQueue.Entry; import org.apache.lucene.util.PriorityQueue; /** * A {@link Collector} that sorts by {@link SortField} using * {@link FieldComparator}s. * <p/> * See the {@link #create(org.apache.lucene.search.Sort, int, boolean, boolean, boolean, boolean)} method * for instantiating a TopFieldCollector. * * @lucene.experimental */ public abstract class TopFieldCollector extends TopDocsCollector<Entry> { // TODO: one optimization we could do is to pre-fill // the queue with sentinel value that guaranteed to // always compare lower than a real hit; this would // save having to check queueFull on each insert /* * Implements a TopFieldCollector over one SortField criteria, without * tracking document scores and maxScore. */ private static class OneComparatorNonScoringCollector extends TopFieldCollector { final FieldComparator comparator; final int reverseMul; public OneComparatorNonScoringCollector(FieldValueHitQueue queue, int numHits, boolean fillFields) throws IOException { super(queue, numHits, fillFields); comparator = queue.getComparators()[0]; reverseMul = queue.getReverseMul()[0]; } final void updateBottom(int doc) { // bottom.score is already set to Float.NaN in add(). bottom.doc = docBase + doc; bottom = pq.updateTop(); } @Override public void collect(int doc) throws IOException { ++totalHits; if (queueFull) { if ((reverseMul * comparator.compareBottom(doc)) <= 0) { // since docs are visited in doc Id order, if compare is 0, it means // this document is largest than anything else in the queue, and // therefore not competitive. return; } // This hit is competitive - replace bottom element in queue & adjustTop comparator.copy(bottom.slot, doc); updateBottom(doc); comparator.setBottom(bottom.slot); } else { // Startup transient: queue hasn't gathered numHits yet final int slot = totalHits - 1; // Copy hit into queue comparator.copy(slot, doc); add(slot, doc, Float.NaN); if (queueFull) { comparator.setBottom(bottom.slot); } } } @Override public void setNextReader(IndexReader reader, int docBase) throws IOException { this.docBase = docBase; comparator.setNextReader(reader, docBase); } @Override public void setScorer(Scorer scorer) throws IOException { comparator.setScorer(scorer); } } /* * Implements a TopFieldCollector over one SortField criteria, without * tracking document scores and maxScore, and assumes out of orderness in doc * Ids collection. */ private static class OutOfOrderOneComparatorNonScoringCollector extends OneComparatorNonScoringCollector { public OutOfOrderOneComparatorNonScoringCollector(FieldValueHitQueue queue, int numHits, boolean fillFields) throws IOException { super(queue, numHits, fillFields); } @Override public void collect(int doc) throws IOException { ++totalHits; if (queueFull) { // Fastmatch: return if this hit is not competitive final int cmp = reverseMul * comparator.compareBottom(doc); if (cmp < 0 || (cmp == 0 && doc + docBase > bottom.doc)) { return; } // This hit is competitive - replace bottom element in queue & adjustTop comparator.copy(bottom.slot, doc); updateBottom(doc); comparator.setBottom(bottom.slot); } else { // Startup transient: queue hasn't gathered numHits yet final int slot = totalHits - 1; // Copy hit into queue comparator.copy(slot, doc); add(slot, doc, Float.NaN); if (queueFull) { comparator.setBottom(bottom.slot); } } } @Override public boolean acceptsDocsOutOfOrder() { return true; } } /* * Implements a TopFieldCollector over one SortField criteria, while tracking * document scores but no maxScore. */ private static class OneComparatorScoringNoMaxScoreCollector extends OneComparatorNonScoringCollector { Scorer scorer; public OneComparatorScoringNoMaxScoreCollector(FieldValueHitQueue queue, int numHits, boolean fillFields) throws IOException { super(queue, numHits, fillFields); } final void updateBottom(int doc, float score) { bottom.doc = docBase + doc; bottom.score = score; bottom = pq.updateTop(); } @Override public void collect(int doc) throws IOException { ++totalHits; if (queueFull) { if ((reverseMul * comparator.compareBottom(doc)) <= 0) { // since docs are visited in doc Id order, if compare is 0, it means // this document is largest than anything else in the queue, and // therefore not competitive. return; } // Compute the score only if the hit is competitive. final float score = scorer.score(); // This hit is competitive - replace bottom element in queue & adjustTop comparator.copy(bottom.slot, doc); updateBottom(doc, score); comparator.setBottom(bottom.slot); } else { // Compute the score only if the hit is competitive. final float score = scorer.score(); // Startup transient: queue hasn't gathered numHits yet final int slot = totalHits - 1; // Copy hit into queue comparator.copy(slot, doc); add(slot, doc, score); if (queueFull) { comparator.setBottom(bottom.slot); } } } @Override public void setScorer(Scorer scorer) throws IOException { this.scorer = scorer; comparator.setScorer(scorer); } } /* * Implements a TopFieldCollector over one SortField criteria, while tracking * document scores but no maxScore, and assumes out of orderness in doc Ids * collection. */ private static class OutOfOrderOneComparatorScoringNoMaxScoreCollector extends OneComparatorScoringNoMaxScoreCollector { public OutOfOrderOneComparatorScoringNoMaxScoreCollector( FieldValueHitQueue queue, int numHits, boolean fillFields) throws IOException { super(queue, numHits, fillFields); } @Override public void collect(int doc) throws IOException { ++totalHits; if (queueFull) { // Fastmatch: return if this hit is not competitive final int cmp = reverseMul * comparator.compareBottom(doc); if (cmp < 0 || (cmp == 0 && doc + docBase > bottom.doc)) { return; } // Compute the score only if the hit is competitive. final float score = scorer.score(); // This hit is competitive - replace bottom element in queue & adjustTop comparator.copy(bottom.slot, doc); updateBottom(doc, score); comparator.setBottom(bottom.slot); } else { // Compute the score only if the hit is competitive. final float score = scorer.score(); // Startup transient: queue hasn't gathered numHits yet final int slot = totalHits - 1; // Copy hit into queue comparator.copy(slot, doc); add(slot, doc, score); if (queueFull) { comparator.setBottom(bottom.slot); } } } @Override public boolean acceptsDocsOutOfOrder() { return true; } } /* * Implements a TopFieldCollector over one SortField criteria, with tracking * document scores and maxScore. */ private static class OneComparatorScoringMaxScoreCollector extends OneComparatorNonScoringCollector { Scorer scorer; public OneComparatorScoringMaxScoreCollector(FieldValueHitQueue queue, int numHits, boolean fillFields) throws IOException { super(queue, numHits, fillFields); // Must set maxScore to NEG_INF, or otherwise Math.max always returns NaN. maxScore = Float.NEGATIVE_INFINITY; } final void updateBottom(int doc, float score) { bottom.doc = docBase + doc; bottom.score = score; bottom = pq.updateTop(); } @Override public void collect(int doc) throws IOException { final float score = scorer.score(); if (score > maxScore) { maxScore = score; } ++totalHits; if (queueFull) { if ((reverseMul * comparator.compareBottom(doc)) <= 0) { // since docs are visited in doc Id order, if compare is 0, it means // this document is largest than anything else in the queue, and // therefore not competitive. return; } // This hit is competitive - replace bottom element in queue & adjustTop comparator.copy(bottom.slot, doc); updateBottom(doc, score); comparator.setBottom(bottom.slot); } else { // Startup transient: queue hasn't gathered numHits yet final int slot = totalHits - 1; // Copy hit into queue comparator.copy(slot, doc); add(slot, doc, score); if (queueFull) { comparator.setBottom(bottom.slot); } } } @Override public void setScorer(Scorer scorer) throws IOException { this.scorer = scorer; super.setScorer(scorer); } } /* * Implements a TopFieldCollector over one SortField criteria, with tracking * document scores and maxScore, and assumes out of orderness in doc Ids * collection. */ private static class OutOfOrderOneComparatorScoringMaxScoreCollector extends OneComparatorScoringMaxScoreCollector { public OutOfOrderOneComparatorScoringMaxScoreCollector(FieldValueHitQueue queue, int numHits, boolean fillFields) throws IOException { super(queue, numHits, fillFields); } @Override public void collect(int doc) throws IOException { final float score = scorer.score(); if (score > maxScore) { maxScore = score; } ++totalHits; if (queueFull) { // Fastmatch: return if this hit is not competitive final int cmp = reverseMul * comparator.compareBottom(doc); if (cmp < 0 || (cmp == 0 && doc + docBase > bottom.doc)) { return; } // This hit is competitive - replace bottom element in queue & adjustTop comparator.copy(bottom.slot, doc); updateBottom(doc, score); comparator.setBottom(bottom.slot); } else { // Startup transient: queue hasn't gathered numHits yet final int slot = totalHits - 1; // Copy hit into queue comparator.copy(slot, doc); add(slot, doc, score); if (queueFull) { comparator.setBottom(bottom.slot); } } } @Override public boolean acceptsDocsOutOfOrder() { return true; } } /* * Implements a TopFieldCollector over multiple SortField criteria, without * tracking document scores and maxScore. */ private static class MultiComparatorNonScoringCollector extends TopFieldCollector { final FieldComparator[] comparators; final int[] reverseMul; public MultiComparatorNonScoringCollector(FieldValueHitQueue queue, int numHits, boolean fillFields) throws IOException { super(queue, numHits, fillFields); comparators = queue.getComparators(); reverseMul = queue.getReverseMul(); } final void updateBottom(int doc) { // bottom.score is already set to Float.NaN in add(). bottom.doc = docBase + doc; bottom = pq.updateTop(); } @Override public void collect(int doc) throws IOException { ++totalHits; if (queueFull) { // Fastmatch: return if this hit is not competitive for (int i = 0;; i++) { final int c = reverseMul[i] * comparators[i].compareBottom(doc); if (c < 0) { // Definitely not competitive. return; } else if (c > 0) { // Definitely competitive. break; } else if (i == comparators.length - 1) { // Here c=0. If we're at the last comparator, this doc is not // competitive, since docs are visited in doc Id order, which means // this doc cannot compete with any other document in the queue. return; } } // This hit is competitive - replace bottom element in queue & adjustTop for (int i = 0; i < comparators.length; i++) { comparators[i].copy(bottom.slot, doc); } updateBottom(doc); for (int i = 0; i < comparators.length; i++) { comparators[i].setBottom(bottom.slot); } } else { // Startup transient: queue hasn't gathered numHits yet final int slot = totalHits - 1; // Copy hit into queue for (int i = 0; i < comparators.length; i++) { comparators[i].copy(slot, doc); } add(slot, doc, Float.NaN); if (queueFull) { for (int i = 0; i < comparators.length; i++) { comparators[i].setBottom(bottom.slot); } } } } @Override public void setNextReader(IndexReader reader, int docBase) throws IOException { this.docBase = docBase; for (int i = 0; i < comparators.length; i++) { comparators[i].setNextReader(reader, docBase); } } @Override public void setScorer(Scorer scorer) throws IOException { // set the scorer on all comparators for (int i = 0; i < comparators.length; i++) { comparators[i].setScorer(scorer); } } } /* * Implements a TopFieldCollector over multiple SortField criteria, without * tracking document scores and maxScore, and assumes out of orderness in doc * Ids collection. */ private static class OutOfOrderMultiComparatorNonScoringCollector extends MultiComparatorNonScoringCollector { public OutOfOrderMultiComparatorNonScoringCollector(FieldValueHitQueue queue, int numHits, boolean fillFields) throws IOException { super(queue, numHits, fillFields); } @Override public void collect(int doc) throws IOException { ++totalHits; if (queueFull) { // Fastmatch: return if this hit is not competitive for (int i = 0;; i++) { final int c = reverseMul[i] * comparators[i].compareBottom(doc); if (c < 0) { // Definitely not competitive. return; } else if (c > 0) { // Definitely competitive. break; } else if (i == comparators.length - 1) { // This is the equals case. if (doc + docBase > bottom.doc) { // Definitely not competitive return; } break; } } // This hit is competitive - replace bottom element in queue & adjustTop for (int i = 0; i < comparators.length; i++) { comparators[i].copy(bottom.slot, doc); } updateBottom(doc); for (int i = 0; i < comparators.length; i++) { comparators[i].setBottom(bottom.slot); } } else { // Startup transient: queue hasn't gathered numHits yet final int slot = totalHits - 1; // Copy hit into queue for (int i = 0; i < comparators.length; i++) { comparators[i].copy(slot, doc); } add(slot, doc, Float.NaN); if (queueFull) { for (int i = 0; i < comparators.length; i++) { comparators[i].setBottom(bottom.slot); } } } } @Override public boolean acceptsDocsOutOfOrder() { return true; } } /* * Implements a TopFieldCollector over multiple SortField criteria, with * tracking document scores and maxScore. */ private static class MultiComparatorScoringMaxScoreCollector extends MultiComparatorNonScoringCollector { Scorer scorer; public MultiComparatorScoringMaxScoreCollector(FieldValueHitQueue queue, int numHits, boolean fillFields) throws IOException { super(queue, numHits, fillFields); // Must set maxScore to NEG_INF, or otherwise Math.max always returns NaN. maxScore = Float.NEGATIVE_INFINITY; } final void updateBottom(int doc, float score) { bottom.doc = docBase + doc; bottom.score = score; bottom = pq.updateTop(); } @Override public void collect(int doc) throws IOException { final float score = scorer.score(); if (score > maxScore) { maxScore = score; } ++totalHits; if (queueFull) { // Fastmatch: return if this hit is not competitive for (int i = 0;; i++) { final int c = reverseMul[i] * comparators[i].compareBottom(doc); if (c < 0) { // Definitely not competitive. return; } else if (c > 0) { // Definitely competitive. break; } else if (i == comparators.length - 1) { // Here c=0. If we're at the last comparator, this doc is not // competitive, since docs are visited in doc Id order, which means // this doc cannot compete with any other document in the queue. return; } } // This hit is competitive - replace bottom element in queue & adjustTop for (int i = 0; i < comparators.length; i++) { comparators[i].copy(bottom.slot, doc); } updateBottom(doc, score); for (int i = 0; i < comparators.length; i++) { comparators[i].setBottom(bottom.slot); } } else { // Startup transient: queue hasn't gathered numHits yet final int slot = totalHits - 1; // Copy hit into queue for (int i = 0; i < comparators.length; i++) { comparators[i].copy(slot, doc); } add(slot, doc, score); if (queueFull) { for (int i = 0; i < comparators.length; i++) { comparators[i].setBottom(bottom.slot); } } } } @Override public void setScorer(Scorer scorer) throws IOException { this.scorer = scorer; super.setScorer(scorer); } } /* * Implements a TopFieldCollector over multiple SortField criteria, with * tracking document scores and maxScore, and assumes out of orderness in doc * Ids collection. */ private final static class OutOfOrderMultiComparatorScoringMaxScoreCollector extends MultiComparatorScoringMaxScoreCollector { public OutOfOrderMultiComparatorScoringMaxScoreCollector(FieldValueHitQueue queue, int numHits, boolean fillFields) throws IOException { super(queue, numHits, fillFields); } @Override public void collect(int doc) throws IOException { final float score = scorer.score(); if (score > maxScore) { maxScore = score; } ++totalHits; if (queueFull) { // Fastmatch: return if this hit is not competitive for (int i = 0;; i++) { final int c = reverseMul[i] * comparators[i].compareBottom(doc); if (c < 0) { // Definitely not competitive. return; } else if (c > 0) { // Definitely competitive. break; } else if (i == comparators.length - 1) { // This is the equals case. if (doc + docBase > bottom.doc) { // Definitely not competitive return; } break; } } // This hit is competitive - replace bottom element in queue & adjustTop for (int i = 0; i < comparators.length; i++) { comparators[i].copy(bottom.slot, doc); } updateBottom(doc, score); for (int i = 0; i < comparators.length; i++) { comparators[i].setBottom(bottom.slot); } } else { // Startup transient: queue hasn't gathered numHits yet final int slot = totalHits - 1; // Copy hit into queue for (int i = 0; i < comparators.length; i++) { comparators[i].copy(slot, doc); } add(slot, doc, score); if (queueFull) { for (int i = 0; i < comparators.length; i++) { comparators[i].setBottom(bottom.slot); } } } } @Override public boolean acceptsDocsOutOfOrder() { return true; } } /* * Implements a TopFieldCollector over multiple SortField criteria, with * tracking document scores and maxScore. */ private static class MultiComparatorScoringNoMaxScoreCollector extends MultiComparatorNonScoringCollector { Scorer scorer; public MultiComparatorScoringNoMaxScoreCollector(FieldValueHitQueue queue, int numHits, boolean fillFields) throws IOException { super(queue, numHits, fillFields); } final void updateBottom(int doc, float score) { bottom.doc = docBase + doc; bottom.score = score; bottom = pq.updateTop(); } @Override public void collect(int doc) throws IOException { ++totalHits; if (queueFull) { // Fastmatch: return if this hit is not competitive for (int i = 0;; i++) { final int c = reverseMul[i] * comparators[i].compareBottom(doc); if (c < 0) { // Definitely not competitive. return; } else if (c > 0) { // Definitely competitive. break; } else if (i == comparators.length - 1) { // Here c=0. If we're at the last comparator, this doc is not // competitive, since docs are visited in doc Id order, which means // this doc cannot compete with any other document in the queue. return; } } // This hit is competitive - replace bottom element in queue & adjustTop for (int i = 0; i < comparators.length; i++) { comparators[i].copy(bottom.slot, doc); } // Compute score only if it is competitive. final float score = scorer.score(); updateBottom(doc, score); for (int i = 0; i < comparators.length; i++) { comparators[i].setBottom(bottom.slot); } } else { // Startup transient: queue hasn't gathered numHits yet final int slot = totalHits - 1; // Copy hit into queue for (int i = 0; i < comparators.length; i++) { comparators[i].copy(slot, doc); } // Compute score only if it is competitive. final float score = scorer.score(); add(slot, doc, score); if (queueFull) { for (int i = 0; i < comparators.length; i++) { comparators[i].setBottom(bottom.slot); } } } } @Override public void setScorer(Scorer scorer) throws IOException { this.scorer = scorer; super.setScorer(scorer); } } /* * Implements a TopFieldCollector over multiple SortField criteria, with * tracking document scores and maxScore, and assumes out of orderness in doc * Ids collection. */ private final static class OutOfOrderMultiComparatorScoringNoMaxScoreCollector extends MultiComparatorScoringNoMaxScoreCollector { public OutOfOrderMultiComparatorScoringNoMaxScoreCollector( FieldValueHitQueue queue, int numHits, boolean fillFields) throws IOException { super(queue, numHits, fillFields); } @Override public void collect(int doc) throws IOException { ++totalHits; if (queueFull) { // Fastmatch: return if this hit is not competitive for (int i = 0;; i++) { final int c = reverseMul[i] * comparators[i].compareBottom(doc); if (c < 0) { // Definitely not competitive. return; } else if (c > 0) { // Definitely competitive. break; } else if (i == comparators.length - 1) { // This is the equals case. if (doc + docBase > bottom.doc) { // Definitely not competitive return; } break; } } // This hit is competitive - replace bottom element in queue & adjustTop for (int i = 0; i < comparators.length; i++) { comparators[i].copy(bottom.slot, doc); } // Compute score only if it is competitive. final float score = scorer.score(); updateBottom(doc, score); for (int i = 0; i < comparators.length; i++) { comparators[i].setBottom(bottom.slot); } } else { // Startup transient: queue hasn't gathered numHits yet final int slot = totalHits - 1; // Copy hit into queue for (int i = 0; i < comparators.length; i++) { comparators[i].copy(slot, doc); } // Compute score only if it is competitive. final float score = scorer.score(); add(slot, doc, score); if (queueFull) { for (int i = 0; i < comparators.length; i++) { comparators[i].setBottom(bottom.slot); } } } } @Override public void setScorer(Scorer scorer) throws IOException { this.scorer = scorer; super.setScorer(scorer); } @Override public boolean acceptsDocsOutOfOrder() { return true; } } private static final ScoreDoc[] EMPTY_SCOREDOCS = new ScoreDoc[0]; private final boolean fillFields; /* * Stores the maximum score value encountered, needed for normalizing. If * document scores are not tracked, this value is initialized to NaN. */ float maxScore = Float.NaN; final int numHits; FieldValueHitQueue.Entry bottom = null; boolean queueFull; int docBase; // Declaring the constructor private prevents extending this class by anyone // else. Note that the class cannot be final since it's extended by the // internal versions. If someone will define a constructor with any other // visibility, then anyone will be able to extend the class, which is not what // we want. private TopFieldCollector(PriorityQueue<Entry> pq, int numHits, boolean fillFields) { super(pq); this.numHits = numHits; this.fillFields = fillFields; } /** * Creates a new {@link TopFieldCollector} from the given * arguments. * * <p><b>NOTE</b>: The instances returned by this method * pre-allocate a full array of length * <code>numHits</code>. * * @param sort * the sort criteria (SortFields). * @param numHits * the number of results to collect. * @param fillFields * specifies whether the actual field values should be returned on * the results (FieldDoc). * @param trackDocScores * specifies whether document scores should be tracked and set on the * results. Note that if set to false, then the results' scores will * be set to Float.NaN. Setting this to true affects performance, as * it incurs the score computation on each competitive result. * Therefore if document scores are not required by the application, * it is recommended to set it to false. * @param trackMaxScore * specifies whether the query's maxScore should be tracked and set * on the resulting {@link TopDocs}. Note that if set to false, * {@link TopDocs#getMaxScore()} returns Float.NaN. Setting this to * true affects performance as it incurs the score computation on * each result. Also, setting this true automatically sets * <code>trackDocScores</code> to true as well. * @param docsScoredInOrder * specifies whether documents are scored in doc Id order or not by * the given {@link Scorer} in {@link #setScorer(Scorer)}. * @return a {@link TopFieldCollector} instance which will sort the results by * the sort criteria. * @throws IOException */ public static TopFieldCollector create(Sort sort, int numHits, boolean fillFields, boolean trackDocScores, boolean trackMaxScore, boolean docsScoredInOrder) throws IOException { if (sort.fields.length == 0) { throw new IllegalArgumentException("Sort must contain at least one field"); } FieldValueHitQueue queue = FieldValueHitQueue.create(sort.fields, numHits); if (queue.getComparators().length == 1) { if (docsScoredInOrder) { if (trackMaxScore) { return new OneComparatorScoringMaxScoreCollector(queue, numHits, fillFields); } else if (trackDocScores) { return new OneComparatorScoringNoMaxScoreCollector(queue, numHits, fillFields); } else { return new OneComparatorNonScoringCollector(queue, numHits, fillFields); } } else { if (trackMaxScore) { return new OutOfOrderOneComparatorScoringMaxScoreCollector(queue, numHits, fillFields); } else if (trackDocScores) { return new OutOfOrderOneComparatorScoringNoMaxScoreCollector(queue, numHits, fillFields); } else { return new OutOfOrderOneComparatorNonScoringCollector(queue, numHits, fillFields); } } } // multiple comparators. if (docsScoredInOrder) { if (trackMaxScore) { return new MultiComparatorScoringMaxScoreCollector(queue, numHits, fillFields); } else if (trackDocScores) { return new MultiComparatorScoringNoMaxScoreCollector(queue, numHits, fillFields); } else { return new MultiComparatorNonScoringCollector(queue, numHits, fillFields); } } else { if (trackMaxScore) { return new OutOfOrderMultiComparatorScoringMaxScoreCollector(queue, numHits, fillFields); } else if (trackDocScores) { return new OutOfOrderMultiComparatorScoringNoMaxScoreCollector(queue, numHits, fillFields); } else { return new OutOfOrderMultiComparatorNonScoringCollector(queue, numHits, fillFields); } } } final void add(int slot, int doc, float score) { bottom = pq.add(new Entry(slot, docBase + doc, score)); queueFull = totalHits == numHits; } /* * Only the following callback methods need to be overridden since * topDocs(int, int) calls them to return the results. */ @Override protected void populateResults(ScoreDoc[] results, int howMany) { if (fillFields) { // avoid casting if unnecessary. FieldValueHitQueue queue = (FieldValueHitQueue) pq; for (int i = howMany - 1; i >= 0; i--) { results[i] = queue.fillFields(queue.pop()); } } else { for (int i = howMany - 1; i >= 0; i--) { Entry entry = pq.pop(); results[i] = new FieldDoc(entry.doc, entry.score); } } } @Override protected TopDocs newTopDocs(ScoreDoc[] results, int start) { if (results == null) { results = EMPTY_SCOREDOCS; // Set maxScore to NaN, in case this is a maxScore tracking collector. maxScore = Float.NaN; } // If this is a maxScoring tracking collector and there were no results, return new TopFieldDocs(totalHits, results, ((FieldValueHitQueue) pq).getFields(), maxScore); } @Override public boolean acceptsDocsOutOfOrder() { return false; } }