| /* |
| * 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.expressions; |
| |
| |
| import java.io.IOException; |
| import java.util.List; |
| |
| import org.apache.lucene.index.LeafReaderContext; |
| import org.apache.lucene.index.ReaderUtil; |
| import org.apache.lucene.search.DoubleValues; |
| import org.apache.lucene.search.Explanation; |
| import org.apache.lucene.search.IndexSearcher; |
| import org.apache.lucene.search.Rescorer; |
| import org.apache.lucene.search.Sort; |
| import org.apache.lucene.search.SortRescorer; |
| |
| /** |
| * A {@link Rescorer} that uses an expression to re-score |
| * first pass hits. Functionally this is the same as {@link |
| * SortRescorer} (if you build the {@link Sort} using {@link |
| * Expression#getSortField}), except for the explain method |
| * which gives more detail by showing the value of each |
| * variable. |
| * |
| * @lucene.experimental |
| */ |
| |
| class ExpressionRescorer extends SortRescorer { |
| |
| private final Expression expression; |
| private final Bindings bindings; |
| |
| /** Uses the provided {@link Expression} to assign second |
| * pass scores. */ |
| public ExpressionRescorer(Expression expression, Bindings bindings) { |
| super(new Sort(expression.getSortField(bindings, true))); |
| this.expression = expression; |
| this.bindings = bindings; |
| } |
| |
| private static DoubleValues scores(int doc, float score) { |
| return new DoubleValues() { |
| @Override |
| public double doubleValue() throws IOException { |
| return score; |
| } |
| |
| @Override |
| public boolean advanceExact(int target) throws IOException { |
| assert doc == target; |
| return true; |
| } |
| }; |
| } |
| |
| @Override |
| public Explanation explain(IndexSearcher searcher, Explanation firstPassExplanation, int docID) throws IOException { |
| Explanation superExpl = super.explain(searcher, firstPassExplanation, docID); |
| |
| List<LeafReaderContext> leaves = searcher.getIndexReader().leaves(); |
| int subReader = ReaderUtil.subIndex(docID, leaves); |
| LeafReaderContext readerContext = leaves.get(subReader); |
| int docIDInSegment = docID - readerContext.docBase; |
| |
| return expression.getDoubleValuesSource(bindings).explain(readerContext, docIDInSegment, superExpl); |
| } |
| } |