| using Lucene.Net.Analysis.Miscellaneous; |
| using Lucene.Net.Analysis.Util; |
| using Lucene.Net.Tartarus.Snowball; |
| using System; |
| using System.Collections.Generic; |
| |
| namespace Lucene.Net.Analysis.Snowball |
| { |
| /* |
| * 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> |
| /// Factory for <see cref="SnowballFilter"/>, with configurable language |
| /// <para> |
| /// Note: Use of the "Lovins" stemmer is not recommended, as it is implemented with reflection. |
| /// <code> |
| /// <fieldType name="text_snowballstem" class="solr.TextField" positionIncrementGap="100"> |
| /// <analyzer> |
| /// <tokenizer class="solr.StandardTokenizerFactory"/> |
| /// <filter class="solr.LowerCaseFilterFactory"/> |
| /// <filter class="solr.SnowballPorterFilterFactory" protected="protectedkeyword.txt" language="English"/> |
| /// </analyzer> |
| /// </fieldType></code> |
| /// </para> |
| /// </summary> |
| public class SnowballPorterFilterFactory : TokenFilterFactory, IResourceLoaderAware |
| { |
| public const string PROTECTED_TOKENS = "protected"; |
| |
| private readonly string language; |
| private readonly string wordFiles; |
| private Type stemClass; |
| private CharArraySet protectedWords = null; |
| |
| /// <summary> |
| /// Creates a new <see cref="SnowballPorterFilterFactory"/> </summary> |
| public SnowballPorterFilterFactory(IDictionary<string, string> args) : base(args) |
| { |
| language = Get(args, "language", "English"); |
| wordFiles = Get(args, PROTECTED_TOKENS); |
| if (args.Count > 0) |
| { |
| throw new ArgumentException(string.Format(J2N.Text.StringFormatter.CurrentCulture, "Unknown parameters: {0}", args)); |
| } |
| } |
| |
| public virtual void Inform(IResourceLoader loader) |
| { |
| string className = typeof(SnowballProgram).Namespace + ".Ext." + |
| language + "Stemmer, " + this.GetType().Assembly.GetName().Name; |
| stemClass = Type.GetType(className); |
| |
| if (wordFiles != null) |
| { |
| protectedWords = GetWordSet(loader, wordFiles, false); |
| } |
| } |
| |
| public override TokenStream Create(TokenStream input) |
| { |
| SnowballProgram program; |
| try |
| { |
| program = (SnowballProgram)Activator.CreateInstance(stemClass); |
| } |
| catch (Exception e) |
| { |
| throw new Exception("Error instantiating stemmer for language " + language + "from class " + stemClass, e); |
| } |
| |
| if (protectedWords != null) |
| { |
| input = new SetKeywordMarkerFilter(input, protectedWords); |
| } |
| return new SnowballFilter(input, program); |
| } |
| } |
| } |