| /* |
| * 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.valuesource; |
| |
| import java.io.IOException; |
| import java.util.Map; |
| |
| import org.apache.lucene.index.LeafReaderContext; |
| import org.apache.lucene.queries.function.FunctionValues; |
| import org.apache.lucene.queries.function.ValueSource; |
| import org.apache.lucene.queries.function.docvalues.FloatDocValues; |
| import org.apache.lucene.search.CollectionStatistics; |
| import org.apache.lucene.search.IndexSearcher; |
| import org.apache.lucene.search.LeafSimScorer; |
| import org.apache.lucene.search.TermStatistics; |
| import org.apache.lucene.search.similarities.TFIDFSimilarity; |
| import org.apache.lucene.util.BytesRef; |
| import org.apache.lucene.search.similarities.Similarity.SimScorer; |
| |
| /** |
| * Function that returns the decoded norm for every document. |
| * <p> |
| * Note that the configured Similarity for the field must be |
| * a subclass of {@link TFIDFSimilarity} and the contribution of |
| * the TF needs to be 1 when the freq is 1 and the contribution |
| * of the IDF needs to be 1 when docFreq == docCount == 1. |
| * @lucene.internal */ |
| public class NormValueSource extends ValueSource { |
| protected final String field; |
| public NormValueSource(String field) { |
| this.field = field; |
| } |
| |
| public String name() { |
| return "norm"; |
| } |
| |
| @Override |
| public String description() { |
| return name() + '(' + field + ')'; |
| } |
| |
| @Override |
| public void createWeight(Map context, IndexSearcher searcher) throws IOException { |
| context.put("searcher",searcher); |
| } |
| |
| @Override |
| public FunctionValues getValues(Map context, LeafReaderContext readerContext) throws IOException { |
| IndexSearcher searcher = (IndexSearcher)context.get("searcher"); |
| final TFIDFSimilarity similarity = IDFValueSource.asTFIDF(searcher.getSimilarity(), field); |
| if (similarity == null) { |
| throw new UnsupportedOperationException("requires a TFIDFSimilarity (such as ClassicSimilarity)"); |
| } |
| // Only works if the contribution of the tf is 1 when the freq is 1 and contribution of the idf |
| // is 1 when docCount == docFreq == 1 |
| final SimScorer simScorer = similarity.scorer(1f, |
| new CollectionStatistics(field, 1, 1, 1, 1), |
| new TermStatistics(new BytesRef("bogus"), 1, 1)); |
| final LeafSimScorer leafSimScorer = new LeafSimScorer(simScorer, readerContext.reader(), field, true); |
| |
| return new FloatDocValues(this) { |
| int lastDocID = -1; |
| @Override |
| public float floatVal(int docID) throws IOException { |
| if (docID < lastDocID) { |
| throw new AssertionError("docs out of order: lastDocID=" + lastDocID + " docID=" + docID); |
| } |
| lastDocID = docID; |
| return leafSimScorer.score(docID, 1f); |
| } |
| }; |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (this.getClass() != o.getClass()) { |
| return false; |
| } |
| return this.field.equals(((NormValueSource)o).field); |
| } |
| |
| @Override |
| public int hashCode() { |
| return this.getClass().hashCode() + field.hashCode(); |
| } |
| } |
| |
| |