| using Lucene.Net.Analysis.Core; |
| using Lucene.Net.Analysis.Miscellaneous; |
| using Lucene.Net.Analysis.Snowball; |
| using Lucene.Net.Analysis.Standard; |
| using Lucene.Net.Analysis.Util; |
| using Lucene.Net.Util; |
| using System; |
| using System.IO; |
| using System.Text; |
| |
| namespace Lucene.Net.Analysis.Ru |
| { |
| /* |
| * 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> |
| /// <see cref="Analyzer"/> for Russian language. |
| /// <para> |
| /// Supports an external list of stopwords (words that |
| /// will not be indexed at all). |
| /// A default set of stopwords is used unless an alternative list is specified. |
| /// </para> |
| /// <para>You must specify the required <see cref="LuceneVersion"/> |
| /// compatibility when creating <see cref="RussianAnalyzer"/>: |
| /// <list type="bullet"> |
| /// <item><description> As of 3.1, <see cref="StandardTokenizer"/> is used, Snowball stemming is done with |
| /// <see cref="SnowballFilter"/>, and Snowball stopwords are used by default.</description></item> |
| /// </list> |
| /// </para> |
| /// </summary> |
| public sealed class RussianAnalyzer : StopwordAnalyzerBase |
| { |
| /// <summary> |
| /// List of typical Russian stopwords. (for backwards compatibility) </summary> |
| /// @deprecated (3.1) Remove this for LUCENE 5.0 |
| [Obsolete("(3.1) Remove this for LUCENE 5.0")] |
| private static readonly string[] RUSSIAN_STOP_WORDS_30 = new string[] { |
| "а", "без", "более", "бы", "был", "была", "были", "было", "быть", "в", |
| "вам", "вас", "весь", "во", "вот", "все", "всего", "всех", "вы", "где", |
| "да", "даже", "для", "до", "его", "ее", "ей", "ею", "если", "есть", |
| "еще", "же", "за", "здесь", "и", "из", "или", "им", "их", "к", "как", |
| "ко", "когда", "кто", "ли", "либо", "мне", "может", "мы", "на", "надо", |
| "наш", "не", "него", "нее", "нет", "ни", "них", "но", "ну", "о", "об", |
| "однако", "он", "она", "они", "оно", "от", "очень", "по", "под", "при", |
| "с", "со", "так", "также", "такой", "там", "те", "тем", "то", "того", |
| "тоже", "той", "только", "том", "ты", "у", "уже", "хотя", "чего", "чей", |
| "чем", "что", "чтобы", "чье", "чья", "эта", "эти", "это", "я" |
| }; |
| |
| /// <summary> |
| /// File containing default Russian stopwords. </summary> |
| public const string DEFAULT_STOPWORD_FILE = "russian_stop.txt"; |
| |
| private class DefaultSetHolder |
| { |
| /// @deprecated (3.1) remove this for Lucene 5.0 |
| [Obsolete("(3.1) remove this for Lucene 5.0")] |
| internal static readonly CharArraySet DEFAULT_STOP_SET_30 = CharArraySet.UnmodifiableSet(new CharArraySet(LuceneVersion.LUCENE_CURRENT, RUSSIAN_STOP_WORDS_30, false)); |
| internal static readonly CharArraySet DEFAULT_STOP_SET = LoadDefaultStopSet(); |
| |
| private static CharArraySet LoadDefaultStopSet() // LUCENENET: Avoid static constructors (see https://github.com/apache/lucenenet/pull/224#issuecomment-469284006) |
| { |
| try |
| { |
| return WordlistLoader.GetSnowballWordSet( |
| IOUtils.GetDecodingReader(typeof(SnowballFilter), DEFAULT_STOPWORD_FILE, Encoding.UTF8), |
| #pragma warning disable 612, 618 |
| LuceneVersion.LUCENE_CURRENT); |
| #pragma warning restore 612, 618 |
| } |
| catch (IOException ex) |
| { |
| // default set should always be present as it is part of the |
| // distribution (JAR) |
| throw new Exception("Unable to load default stopword set", ex); |
| } |
| } |
| } |
| |
| private readonly CharArraySet stemExclusionSet; |
| |
| /// <summary> |
| /// Returns an unmodifiable instance of the default stop-words set. |
| /// </summary> |
| /// <returns> an unmodifiable instance of the default stop-words set. </returns> |
| public static CharArraySet DefaultStopSet |
| { |
| get |
| { |
| return DefaultSetHolder.DEFAULT_STOP_SET; |
| } |
| } |
| |
| public RussianAnalyzer(LuceneVersion matchVersion) |
| #pragma warning disable 612, 618 |
| : this(matchVersion, matchVersion.OnOrAfter(LuceneVersion.LUCENE_31) ? |
| DefaultSetHolder.DEFAULT_STOP_SET : DefaultSetHolder.DEFAULT_STOP_SET_30) |
| #pragma warning restore 612, 618 |
| { |
| } |
| |
| /// <summary> |
| /// Builds an analyzer with the given stop words |
| /// </summary> |
| /// <param name="matchVersion"> |
| /// lucene compatibility version </param> |
| /// <param name="stopwords"> |
| /// a stopword set </param> |
| public RussianAnalyzer(LuceneVersion matchVersion, CharArraySet stopwords) |
| : this(matchVersion, stopwords, CharArraySet.EMPTY_SET) |
| { |
| } |
| |
| /// <summary> |
| /// Builds an analyzer with the given stop words |
| /// </summary> |
| /// <param name="matchVersion"> |
| /// lucene compatibility version </param> |
| /// <param name="stopwords"> |
| /// a stopword set </param> |
| /// <param name="stemExclusionSet"> a set of words not to be stemmed </param> |
| public RussianAnalyzer(LuceneVersion matchVersion, CharArraySet stopwords, CharArraySet stemExclusionSet) |
| : base(matchVersion, stopwords) |
| { |
| this.stemExclusionSet = CharArraySet.UnmodifiableSet(CharArraySet.Copy(matchVersion, stemExclusionSet)); |
| } |
| |
| /// <summary> |
| /// Creates |
| /// <see cref="TokenStreamComponents"/> |
| /// used to tokenize all the text in the provided <see cref="TextReader"/>. |
| /// </summary> |
| /// <returns> <see cref="TokenStreamComponents"/> |
| /// built from a <see cref="StandardTokenizer"/> filtered with |
| /// <see cref="StandardFilter"/>, <see cref="LowerCaseFilter"/>, <see cref="StopFilter"/> |
| /// , <see cref="SetKeywordMarkerFilter"/> if a stem exclusion set is |
| /// provided, and <see cref="SnowballFilter"/> </returns> |
| protected override TokenStreamComponents CreateComponents(string fieldName, TextReader reader) |
| { |
| #pragma warning disable 612, 618 |
| if (m_matchVersion.OnOrAfter(LuceneVersion.LUCENE_31)) |
| #pragma warning restore 612, 618 |
| { |
| Tokenizer source = new StandardTokenizer(m_matchVersion, reader); |
| TokenStream result = new StandardFilter(m_matchVersion, source); |
| result = new LowerCaseFilter(m_matchVersion, result); |
| result = new StopFilter(m_matchVersion, result, m_stopwords); |
| if (stemExclusionSet.Count > 0) |
| { |
| result = new SetKeywordMarkerFilter(result, stemExclusionSet); |
| } |
| result = new SnowballFilter(result, new Tartarus.Snowball.Ext.RussianStemmer()); |
| return new TokenStreamComponents(source, result); |
| } |
| else |
| { |
| #pragma warning disable 612, 618 |
| Tokenizer source = new RussianLetterTokenizer(m_matchVersion, reader); |
| #pragma warning restore 612, 618 |
| TokenStream result = new LowerCaseFilter(m_matchVersion, source); |
| result = new StopFilter(m_matchVersion, result, m_stopwords); |
| if (stemExclusionSet.Count > 0) |
| { |
| result = new SetKeywordMarkerFilter(result, stemExclusionSet); |
| } |
| result = new SnowballFilter(result, new Tartarus.Snowball.Ext.RussianStemmer()); |
| return new TokenStreamComponents(source, result); |
| } |
| } |
| } |
| } |
