/* * 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.spatial.util; import java.io.IOException; import java.util.Objects; import org.apache.lucene.index.LeafReaderContext; import org.apache.lucene.search.DoubleValues; import org.apache.lucene.search.DoubleValuesSource; import org.apache.lucene.search.Explanation; import org.apache.lucene.search.IndexSearcher; /** * Transforms a DoubleValuesSource using the formula v = k / (v + k) */ public class ReciprocalDoubleValuesSource extends DoubleValuesSource { private final double distToEdge; private final DoubleValuesSource input; /** * Creates a ReciprocalDoubleValuesSource * @param distToEdge the value k in v = k / (v + k) * @param input the input DoubleValuesSource to transform */ public ReciprocalDoubleValuesSource(double distToEdge, DoubleValuesSource input) { this.distToEdge = distToEdge; this.input = input; } @Override public DoubleValues getValues(LeafReaderContext ctx, DoubleValues scores) throws IOException { DoubleValues in = input.getValues(ctx, scores); return new DoubleValues() { @Override public double doubleValue() throws IOException { return recip(in.doubleValue()); } @Override public boolean advanceExact(int doc) throws IOException { return in.advanceExact(doc); } }; } private double recip(double in) { return distToEdge / (in + distToEdge); } @Override public boolean needsScores() { return input.needsScores(); } @Override public boolean isCacheable(LeafReaderContext ctx) { return input.isCacheable(ctx); } @Override public Explanation explain(LeafReaderContext ctx, int docId, Explanation scoreExplanation) throws IOException { Explanation expl = input.explain(ctx, docId, scoreExplanation); return Explanation.match(recip(expl.getValue().doubleValue()), distToEdge + " / (v + " + distToEdge + "), computed from:", expl); } @Override public DoubleValuesSource rewrite(IndexSearcher searcher) throws IOException { return new ReciprocalDoubleValuesSource(distToEdge, input.rewrite(searcher)); } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; ReciprocalDoubleValuesSource that = (ReciprocalDoubleValuesSource) o; return Double.compare(that.distToEdge, distToEdge) == 0 && Objects.equals(input, that.input); } @Override public int hashCode() { return Objects.hash(distToEdge, input); } @Override public String toString() { return "recip(" + distToEdge + ", " + input.toString() + ")"; } }