| // Lucene version compatibility level 4.8.1 |
| using Lucene.Net.Index; |
| using Lucene.Net.Queries.Function.DocValues; |
| using Lucene.Net.Search; |
| using Lucene.Net.Search.Similarities; |
| using Lucene.Net.Util; |
| using System; |
| using System.Collections; |
| using System.IO; |
| |
| namespace Lucene.Net.Queries.Function.ValueSources |
| { |
| /* |
| * 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. |
| */ |
| |
| /// <summary> |
| /// Function that returns <see cref="TFIDFSimilarity.Tf(float)"/> |
| /// for every document. |
| /// <para/> |
| /// Note that the configured Similarity for the field must be |
| /// a subclass of <see cref="TFIDFSimilarity"/> |
| /// @lucene.internal |
| /// </summary> |
| public class TFValueSource : TermFreqValueSource |
| { |
| public TFValueSource(string field, string val, string indexedField, BytesRef indexedBytes) |
| : base(field, val, indexedField, indexedBytes) |
| { |
| } |
| |
| public override string Name => "tf"; |
| |
| public override FunctionValues GetValues(IDictionary context, AtomicReaderContext readerContext) |
| { |
| var fields = readerContext.AtomicReader.Fields; |
| var terms = fields.GetTerms(m_indexedField); |
| var searcher = (IndexSearcher)context["searcher"]; |
| var similarity = IDFValueSource.AsTFIDF(searcher.Similarity, m_indexedField); |
| if (similarity == null) |
| { |
| throw new NotSupportedException("requires a TFIDFSimilarity (such as DefaultSimilarity)"); |
| } |
| |
| return new SingleDocValuesAnonymousClass(this, this, terms, similarity); |
| } |
| |
| private class SingleDocValuesAnonymousClass : SingleDocValues |
| { |
| private readonly TFValueSource outerInstance; |
| |
| private readonly Terms terms; |
| private readonly TFIDFSimilarity similarity; |
| |
| public SingleDocValuesAnonymousClass(TFValueSource outerInstance, TFValueSource @this, Terms terms, TFIDFSimilarity similarity) |
| : base(@this) |
| { |
| this.outerInstance = outerInstance; |
| this.terms = terms; |
| this.similarity = similarity; |
| lastDocRequested = -1; |
| Reset(); |
| } |
| |
| private DocsEnum docs; |
| private int atDoc; |
| private int lastDocRequested; |
| |
| public virtual void Reset() |
| { |
| // no one should call us for deleted docs? |
| |
| if (terms != null) |
| { |
| TermsEnum termsEnum = terms.GetEnumerator(); |
| if (termsEnum.SeekExact(outerInstance.m_indexedBytes)) |
| { |
| docs = termsEnum.Docs(null, null); |
| } |
| else |
| { |
| docs = null; |
| } |
| } |
| else |
| { |
| docs = null; |
| } |
| |
| if (docs == null) |
| { |
| docs = new DocsEnumAnonymousClass(); |
| } |
| atDoc = -1; |
| } |
| |
| private class DocsEnumAnonymousClass : DocsEnum |
| { |
| public override int Freq => 0; |
| |
| public override int DocID => DocIdSetIterator.NO_MORE_DOCS; |
| |
| public override int NextDoc() |
| { |
| return DocIdSetIterator.NO_MORE_DOCS; |
| } |
| |
| public override int Advance(int target) |
| { |
| return DocIdSetIterator.NO_MORE_DOCS; |
| } |
| |
| public override long GetCost() |
| { |
| return 0; |
| } |
| } |
| |
| /// <summary> |
| /// NOTE: This was floatVal() in Lucene |
| /// </summary> |
| public override float SingleVal(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 Exception("caught exception in function " + outerInstance.GetDescription() + " : doc=" + doc, e); |
| } |
| } |
| } |
| } |
| } |