/*
* Copyright 2004 The Apache Software Foundation
*
* Licensed 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.
*/
using System;
namespace Lucene.Net.Analysis{
/// <summary>Filters LetterTokenizer with LowerCaseFilter and StopFilter. </summary>
public sealed class StopAnalyzer : Analyzer
{
private System.Collections.Hashtable stopWords;
/// <summary>An array containing some common English words that are not usually useful
/// for searching.
/// </summary>
public static readonly System.String[] ENGLISH_STOP_WORDS = new System.String[]{"a", "an", "and", "are", "as", "at", "be", "but", "by", "for", "if", "in", "into", "is", "it", "no", "not", "of", "on", "or", "s", "such", "t", "that", "the", "their", "then", "there", "these", "they", "this", "to", "was", "will", "with"};
/// <summary>Builds an analyzer which removes words in ENGLISH_STOP_WORDS. </summary>
public StopAnalyzer()
{
stopWords = StopFilter.MakeStopSet(ENGLISH_STOP_WORDS);
}
/// <summary>Builds an analyzer with the stop words from the given set.</summary>
public StopAnalyzer(System.Collections.Hashtable stopWords)
{
this.stopWords = stopWords;
}
/// <summary>Builds an analyzer which removes words in the provided array. </summary>
public StopAnalyzer(System.String[] stopWords)
{
this.stopWords = StopFilter.MakeStopSet(stopWords);
}
/// <summary>Builds an analyzer with the stop words from the given file.</summary>
/// <seealso cref="WordlistLoader.GetWordSet(File)">
/// </seealso>
public StopAnalyzer(System.IO.FileInfo stopwordsFile)
{
stopWords = WordlistLoader.GetWordSet(stopwordsFile);
}
/// <summary>Builds an analyzer with the stop words from the given reader.</summary>
/// <seealso cref="WordlistLoader.GetWordSet(Reader)">
/// </seealso>
public StopAnalyzer(System.IO.TextReader stopwords)
{
stopWords = WordlistLoader.GetWordSet(stopwords);
}
/// <summary>Filters LowerCaseTokenizer with StopFilter. </summary>
public override TokenStream TokenStream(System.String fieldName, System.IO.TextReader reader)
{
return new StopFilter(new LowerCaseTokenizer(reader), stopWords);
}
}
}
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