/* * 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.Collection; import java.util.List; import java.util.Objects; import org.apache.lucene.index.LeafReader; import org.apache.lucene.index.NumericDocValues; import org.apache.lucene.search.similarities.Similarity.SimScorer; import org.apache.lucene.util.SmallFloat; import static org.apache.lucene.search.BM25FQuery.FieldAndWeight; /** * Copy of {@link LeafSimScorer} that sums document's norms from multiple fields. */ final class MultiNormsLeafSimScorer { /** * Cache of decoded norms. */ private static final float[] LENGTH_TABLE = new float[256]; static { for (int i = 0; i < 256; i++) { LENGTH_TABLE[i] = SmallFloat.byte4ToInt((byte) i); } } private final SimScorer scorer; private final NumericDocValues norms; /** * Sole constructor: Score documents of {@code reader} with {@code scorer}. * */ MultiNormsLeafSimScorer(SimScorer scorer, LeafReader reader, Collection<FieldAndWeight> normFields, boolean needsScores) throws IOException { this.scorer = Objects.requireNonNull(scorer); if (needsScores) { final List<NumericDocValues> normsList = new ArrayList<>(); final List<Float> weightList = new ArrayList<>(); for (FieldAndWeight field : normFields) { NumericDocValues norms = reader.getNormValues(field.field); if (norms != null) { normsList.add(norms); weightList.add(field.weight); } } if (normsList.isEmpty()) { norms = null; } else if (normsList.size() == 1) { norms = normsList.get(0); } else { final NumericDocValues[] normsArr = normsList.toArray(new NumericDocValues[0]); final float[] weightArr = new float[normsList.size()]; for (int i = 0; i < weightList.size(); i++) { weightArr[i] = weightList.get(i); } norms = new MultiFieldNormValues(normsArr, weightArr); } } else { norms = null; } } private long getNormValue(int doc) throws IOException { if (norms != null) { boolean found = norms.advanceExact(doc); assert found; return norms.longValue(); } else { return 1L; // default norm } } /** Score the provided document assuming the given term document frequency. * This method must be called on non-decreasing sequences of doc ids. * @see SimScorer#score(float, long) */ public float score(int doc, float freq) throws IOException { return scorer.score(freq, getNormValue(doc)); } /** Explain the score for the provided document assuming the given term document frequency. * This method must be called on non-decreasing sequences of doc ids. * @see SimScorer#explain(Explanation, long) */ public Explanation explain(int doc, Explanation freqExpl) throws IOException { return scorer.explain(freqExpl, getNormValue(doc)); } private static class MultiFieldNormValues extends NumericDocValues { private final NumericDocValues[] normsArr; private final float[] weightArr; private long current; private int docID = -1; MultiFieldNormValues(NumericDocValues[] normsArr, float[] weightArr) { this.normsArr = normsArr; this.weightArr = weightArr; } @Override public long longValue() { return current; } @Override public boolean advanceExact(int target) throws IOException { float normValue = 0; for (int i = 0; i < normsArr.length; i++) { boolean found = normsArr[i].advanceExact(target); assert found; normValue += weightArr[i] * LENGTH_TABLE[(byte) normsArr[i].longValue()]; } current = SmallFloat.intToByte4(Math.round(normValue)); return true; } @Override public int docID() { return docID; } @Override public int nextDoc() { throw new UnsupportedOperationException(); } @Override public int advance(int target) { throw new UnsupportedOperationException(); } @Override public long cost() { throw new UnsupportedOperationException(); } } }