| /* |
| * 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.Collection; |
| import java.util.Comparator; |
| import java.util.List; |
| |
| /** |
| * Scorer for conjunctions that checks the maximum scores of each clause in |
| * order to potentially skip over blocks that can't have competitive matches. |
| */ |
| final class BlockMaxConjunctionScorer extends Scorer { |
| final Scorer[] scorers; |
| final DocIdSetIterator[] approximations; |
| final TwoPhaseIterator[] twoPhases; |
| final MaxScoreSumPropagator maxScorePropagator; |
| float minScore; |
| |
| /** Create a new {@link BlockMaxConjunctionScorer} from scoring clauses. */ |
| BlockMaxConjunctionScorer(Weight weight, Collection<Scorer> scorersList) throws IOException { |
| super(weight); |
| this.scorers = scorersList.toArray(new Scorer[scorersList.size()]); |
| // Sort scorer by cost |
| Arrays.sort(this.scorers, Comparator.comparingLong(s -> s.iterator().cost())); |
| this.maxScorePropagator = new MaxScoreSumPropagator(Arrays.asList(scorers)); |
| |
| this.approximations = new DocIdSetIterator[scorers.length]; |
| List<TwoPhaseIterator> twoPhaseList = new ArrayList<>(); |
| for (int i = 0; i < scorers.length; i++) { |
| Scorer scorer = scorers[i]; |
| TwoPhaseIterator twoPhase = scorer.twoPhaseIterator(); |
| if (twoPhase != null) { |
| twoPhaseList.add(twoPhase); |
| approximations[i] = twoPhase.approximation(); |
| } else { |
| approximations[i] = scorer.iterator(); |
| } |
| scorer.advanceShallow(0); |
| } |
| this.twoPhases = twoPhaseList.toArray(new TwoPhaseIterator[twoPhaseList.size()]); |
| Arrays.sort(this.twoPhases, Comparator.comparingDouble(TwoPhaseIterator::matchCost)); |
| } |
| |
| @Override |
| public TwoPhaseIterator twoPhaseIterator() { |
| if (twoPhases.length == 0) { |
| return null; |
| } |
| float matchCost = (float) Arrays.stream(twoPhases) |
| .mapToDouble(TwoPhaseIterator::matchCost) |
| .sum(); |
| final DocIdSetIterator approx = approximation(); |
| return new TwoPhaseIterator(approx) { |
| @Override |
| public boolean matches() throws IOException { |
| for (TwoPhaseIterator twoPhase : twoPhases) { |
| assert twoPhase.approximation().docID() == docID(); |
| if (twoPhase.matches() == false) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| @Override |
| public float matchCost() { |
| return matchCost; |
| } |
| }; |
| } |
| |
| @Override |
| public DocIdSetIterator iterator() { |
| return twoPhases.length == 0 ? approximation() : |
| TwoPhaseIterator.asDocIdSetIterator(twoPhaseIterator()); |
| } |
| |
| private DocIdSetIterator approximation() { |
| final DocIdSetIterator lead = approximations[0]; |
| |
| return new DocIdSetIterator() { |
| |
| float maxScore; |
| int upTo = -1; |
| |
| @Override |
| public int docID() { |
| return lead.docID(); |
| } |
| |
| @Override |
| public long cost() { |
| return lead.cost(); |
| } |
| |
| private void moveToNextBlock(int target) throws IOException { |
| upTo = advanceShallow(target); |
| maxScore = getMaxScore(upTo); |
| } |
| |
| private int advanceTarget(int target) throws IOException { |
| if (target > upTo) { |
| moveToNextBlock(target); |
| } |
| |
| while (true) { |
| assert upTo >= target; |
| |
| if (maxScore >= minScore) { |
| return target; |
| } |
| |
| if (upTo == NO_MORE_DOCS) { |
| return NO_MORE_DOCS; |
| } |
| |
| target = upTo + 1; |
| |
| moveToNextBlock(target); |
| } |
| } |
| |
| @Override |
| public int nextDoc() throws IOException { |
| return advance(docID() + 1); |
| } |
| |
| @Override |
| public int advance(int target) throws IOException { |
| return doNext(lead.advance(advanceTarget(target))); |
| } |
| |
| private int doNext(int doc) throws IOException { |
| advanceHead: for(;;) { |
| assert doc == lead.docID(); |
| |
| if (doc == NO_MORE_DOCS) { |
| return NO_MORE_DOCS; |
| } |
| |
| if (doc > upTo) { |
| // This check is useful when scorers return information about blocks |
| // that do not actually have any matches. Otherwise `doc` will always |
| // be in the current block already since it is always the result of |
| // lead.advance(advanceTarget(some_doc_id)) |
| final int nextTarget = advanceTarget(doc); |
| if (nextTarget != doc) { |
| doc = lead.advance(nextTarget); |
| continue; |
| } |
| } |
| |
| assert doc <= upTo; |
| |
| // then find agreement with other iterators |
| for (int i = 1; i < approximations.length; ++i) { |
| final DocIdSetIterator other = approximations[i]; |
| // other.doc may already be equal to doc if we "continued advanceHead" |
| // on the previous iteration and the advance on the lead scorer exactly matched. |
| if (other.docID() < doc) { |
| final int next = other.advance(doc); |
| |
| if (next > doc) { |
| // iterator beyond the current doc - advance lead and continue to the new highest doc. |
| doc = lead.advance(advanceTarget(next)); |
| continue advanceHead; |
| } |
| } |
| |
| assert other.docID() == doc; |
| } |
| |
| // success - all iterators are on the same doc and the score is competitive |
| return doc; |
| } |
| } |
| }; |
| } |
| |
| @Override |
| public int docID() { |
| return scorers[0].docID(); |
| } |
| |
| @Override |
| public float score() throws IOException { |
| double score = 0; |
| for (Scorer scorer : scorers) { |
| score += scorer.score(); |
| } |
| return (float) score; |
| } |
| |
| @Override |
| public int advanceShallow(int target) throws IOException { |
| // We use block boundaries of the lead scorer. |
| // It is tempting to fold in other clauses as well to have better bounds of |
| // the score, but then there is a risk of not progressing fast enough. |
| int result = scorers[0].advanceShallow(target); |
| // But we still need to shallow-advance other clauses, in order to have |
| // better score upper bounds |
| for (int i = 1; i < scorers.length; ++i) { |
| scorers[i].advanceShallow(target); |
| } |
| return result; |
| } |
| |
| @Override |
| public float getMaxScore(int upTo) throws IOException { |
| double sum = 0; |
| for (Scorer scorer : scorers) { |
| sum += scorer.getMaxScore(upTo); |
| } |
| return (float) sum; |
| } |
| |
| @Override |
| public void setMinCompetitiveScore(float score) throws IOException { |
| minScore = score; |
| maxScorePropagator.setMinCompetitiveScore(score); |
| } |
| |
| @Override |
| public Collection<ChildScorable> getChildren() { |
| ArrayList<ChildScorable> children = new ArrayList<>(); |
| for (Scorer scorer : scorers) { |
| children.add(new ChildScorable(scorer, "MUST")); |
| } |
| return children; |
| } |
| } |