| /* |
| * 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.index.PostingsEnum; |
| import org.apache.lucene.index.Terms; |
| import org.apache.lucene.index.TermsEnum; |
| import org.apache.lucene.queries.function.FunctionValues; |
| import org.apache.lucene.queries.function.docvalues.FloatDocValues; |
| import org.apache.lucene.search.DocIdSetIterator; |
| import org.apache.lucene.search.IndexSearcher; |
| import org.apache.lucene.search.similarities.TFIDFSimilarity; |
| import org.apache.lucene.util.BytesRef; |
| |
| /** |
| * Function that returns {@link TFIDFSimilarity#tf(float)} |
| * for every document. |
| * <p> |
| * Note that the configured Similarity for the field must be |
| * a subclass of {@link TFIDFSimilarity} |
| * @lucene.internal */ |
| public class TFValueSource extends TermFreqValueSource { |
| public TFValueSource(String field, String val, String indexedField, BytesRef indexedBytes) { |
| super(field, val, indexedField, indexedBytes); |
| } |
| |
| @Override |
| public String name() { |
| return "tf"; |
| } |
| |
| @Override |
| public FunctionValues getValues(Map context, LeafReaderContext readerContext) throws IOException { |
| final Terms terms = readerContext.reader().terms(indexedField); |
| IndexSearcher searcher = (IndexSearcher)context.get("searcher"); |
| final TFIDFSimilarity similarity = IDFValueSource.asTFIDF(searcher.getSimilarity(), indexedField); |
| if (similarity == null) { |
| throw new UnsupportedOperationException("requires a TFIDFSimilarity (such as ClassicSimilarity)"); |
| } |
| |
| return new FloatDocValues(this) { |
| PostingsEnum docs ; |
| int atDoc; |
| int lastDocRequested = -1; |
| |
| { reset(); } |
| |
| public void reset() throws IOException { |
| // no one should call us for deleted docs? |
| |
| if (terms != null) { |
| final TermsEnum termsEnum = terms.iterator(); |
| if (termsEnum.seekExact(indexedBytes)) { |
| docs = termsEnum.postings(null); |
| } else { |
| docs = null; |
| } |
| } else { |
| docs = null; |
| } |
| |
| if (docs == null) { |
| docs = new PostingsEnum() { |
| @Override |
| public int freq() { |
| return 0; |
| } |
| |
| @Override |
| public int nextPosition() throws IOException { |
| return -1; |
| } |
| |
| @Override |
| public int startOffset() throws IOException { |
| return -1; |
| } |
| |
| @Override |
| public int endOffset() throws IOException { |
| return -1; |
| } |
| |
| @Override |
| public BytesRef getPayload() throws IOException { |
| return null; |
| } |
| |
| @Override |
| public int docID() { |
| return DocIdSetIterator.NO_MORE_DOCS; |
| } |
| |
| @Override |
| public int nextDoc() { |
| return DocIdSetIterator.NO_MORE_DOCS; |
| } |
| |
| @Override |
| public int advance(int target) { |
| return DocIdSetIterator.NO_MORE_DOCS; |
| } |
| |
| @Override |
| public long cost() { |
| return 0; |
| } |
| }; |
| } |
| atDoc = -1; |
| } |
| |
| @Override |
| public float floatVal(int doc) { |
| try { |
| if (doc < lastDocRequested) { |
| // out-of-order access.... reset |
| reset(); |
| } |
| lastDocRequested = doc; |
| |
| if (atDoc < doc) { |
| atDoc = docs.advance(doc); |
| } |
| |
| if (atDoc > doc) { |
| // term doesn't match this document... either because we hit the |
| // end, or because the next doc is after this doc. |
| return similarity.tf(0); |
| } |
| |
| // a match! |
| return similarity.tf(docs.freq()); |
| } catch (IOException e) { |
| throw new RuntimeException("caught exception in function "+description()+" : doc="+doc, e); |
| } |
| } |
| }; |
| } |
| } |