| /* |
| * 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.queries.function; |
| |
| import java.io.IOException; |
| |
| import org.apache.lucene.index.LeafReaderContext; |
| import org.apache.lucene.search.DocIdSetIterator; |
| import org.apache.lucene.search.Scorer; |
| import org.apache.lucene.search.TwoPhaseIterator; |
| import org.apache.lucene.search.Weight; |
| |
| /** |
| * {@link Scorer} which returns the result of {@link FunctionValues#floatVal(int)} as |
| * the score for a document, and which filters out documents that don't match {@link #matches(int)}. |
| * This Scorer has a {@link TwoPhaseIterator}. This is similar to {@link FunctionQuery}, |
| * with an added filter. |
| * <p> |
| * Note: If the scores are needed, then the underlying value will probably be |
| * fetched/computed twice -- once to filter and next to return the score. If that's non-trivial then |
| * consider wrapping it in an implementation that will cache the current value. |
| * </p> |
| * |
| * @see FunctionQuery |
| * @lucene.experimental |
| */ |
| public abstract class ValueSourceScorer extends Scorer { |
| protected final FunctionValues values; |
| private final TwoPhaseIterator twoPhaseIterator; |
| private final DocIdSetIterator disi; |
| |
| protected ValueSourceScorer(Weight weight, LeafReaderContext readerContext, FunctionValues values) { |
| super(weight); |
| this.values = values; |
| final DocIdSetIterator approximation = DocIdSetIterator.all(readerContext.reader().maxDoc()); // no approximation! |
| this.twoPhaseIterator = new TwoPhaseIterator(approximation) { |
| @Override |
| public boolean matches() throws IOException { |
| return ValueSourceScorer.this.matches(approximation.docID()); |
| } |
| |
| @Override |
| public float matchCost() { |
| return 100; // TODO: use cost of ValueSourceScorer.this.matches() |
| } |
| }; |
| this.disi = TwoPhaseIterator.asDocIdSetIterator(twoPhaseIterator); |
| } |
| |
| /** Override to decide if this document matches. It's called by {@link TwoPhaseIterator#matches()}. */ |
| public abstract boolean matches(int doc) throws IOException; |
| |
| @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 { |
| // (same as FunctionQuery, but no qWeight) TODO consider adding configurable qWeight |
| float score = values.floatVal(disi.docID()); |
| // Current Lucene priority queues can't handle NaN and -Infinity, so |
| // map to -Float.MAX_VALUE. This conditional handles both -infinity |
| // and NaN since comparisons with NaN are always false. |
| return score > Float.NEGATIVE_INFINITY ? score : -Float.MAX_VALUE; |
| } |
| |
| @Override |
| public float getMaxScore(int upTo) throws IOException { |
| return Float.POSITIVE_INFINITY; |
| } |
| |
| } |