| /* |
| * 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; |
| |
| /** |
| * A constant-scoring {@link Scorer}. |
| * @lucene.internal |
| */ |
| public final class ConstantScoreScorer extends Scorer { |
| |
| private class DocIdSetIteratorWrapper extends DocIdSetIterator { |
| int doc = -1; |
| DocIdSetIterator delegate; |
| |
| DocIdSetIteratorWrapper(DocIdSetIterator delegate) { |
| this.delegate = delegate; |
| } |
| |
| @Override |
| public int docID() { |
| return doc; |
| } |
| |
| @Override |
| public int nextDoc() throws IOException { |
| return doc = delegate.nextDoc(); |
| } |
| |
| @Override |
| public int advance(int target) throws IOException { |
| return doc = delegate.advance(target); |
| } |
| |
| @Override |
| public long cost() { |
| return delegate.cost(); |
| } |
| } |
| |
| private final float score; |
| private final ScoreMode scoreMode; |
| private final DocIdSetIterator approximation; |
| private final TwoPhaseIterator twoPhaseIterator; |
| private final DocIdSetIterator disi; |
| |
| /** Constructor based on a {@link DocIdSetIterator} which will be used to |
| * drive iteration. Two phase iteration will not be supported. |
| * @param weight the parent weight |
| * @param score the score to return on each document |
| * @param scoreMode the score mode |
| * @param disi the iterator that defines matching documents */ |
| public ConstantScoreScorer(Weight weight, float score, ScoreMode scoreMode, DocIdSetIterator disi) { |
| super(weight); |
| this.score = score; |
| this.scoreMode = scoreMode; |
| this.approximation = scoreMode == ScoreMode.TOP_SCORES ? new DocIdSetIteratorWrapper(disi) : disi; |
| this.twoPhaseIterator = null; |
| this.disi = this.approximation; |
| } |
| |
| /** Constructor based on a {@link TwoPhaseIterator}. In that case the |
| * {@link Scorer} will support two-phase iteration. |
| * @param weight the parent weight |
| * @param score the score to return on each document |
| * @param scoreMode the score mode |
| * @param twoPhaseIterator the iterator that defines matching documents */ |
| public ConstantScoreScorer(Weight weight, float score, ScoreMode scoreMode, TwoPhaseIterator twoPhaseIterator) { |
| super(weight); |
| this.score = score; |
| this.scoreMode = scoreMode; |
| if (scoreMode == ScoreMode.TOP_SCORES) { |
| this.approximation = new DocIdSetIteratorWrapper(twoPhaseIterator.approximation()); |
| this.twoPhaseIterator = new TwoPhaseIterator(this.approximation) { |
| @Override |
| public boolean matches() throws IOException { |
| return twoPhaseIterator.matches(); |
| } |
| |
| @Override |
| public float matchCost() { |
| return twoPhaseIterator.matchCost(); |
| } |
| }; |
| } else { |
| this.approximation = twoPhaseIterator.approximation(); |
| this.twoPhaseIterator = twoPhaseIterator; |
| } |
| this.disi = TwoPhaseIterator.asDocIdSetIterator(this.twoPhaseIterator); |
| } |
| |
| @Override |
| public float getMaxScore(int upTo) throws IOException { |
| return score; |
| } |
| |
| @Override |
| public void setMinCompetitiveScore(float minScore) throws IOException { |
| if (scoreMode == ScoreMode.TOP_SCORES && minScore > score) { |
| ((DocIdSetIteratorWrapper) approximation).delegate = DocIdSetIterator.empty(); |
| } |
| } |
| |
| @Override |
| public DocIdSetIterator iterator() { |
| return disi; |
| } |
| |
| @Override |
| public TwoPhaseIterator twoPhaseIterator() { |
| return twoPhaseIterator; |
| } |
| |
| @Override |
| public int docID() { |
| return disi.docID(); |
| } |
| |
| @Override |
| public float score() throws IOException { |
| return score; |
| } |
| |
| } |