LowerCaseTokenizer.cs
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上传日期:2013-09-30
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- /*
- * 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> LowerCaseTokenizer performs the function of LetterTokenizer
- /// and LowerCaseFilter together. It divides text at non-letters and converts
- /// them to lower case. While it is functionally equivalent to the combination
- /// of LetterTokenizer and LowerCaseFilter, there is a performance advantage
- /// to doing the two tasks at once, hence this (redundant) implementation.
- /// <P>
- /// Note: this does a decent job for most European languages, but does a terrible
- /// job for some Asian languages, where words are not separated by spaces.
- /// </summary>
- public sealed class LowerCaseTokenizer : LetterTokenizer
- {
- /// <summary>Construct a new LowerCaseTokenizer. </summary>
- public LowerCaseTokenizer(System.IO.TextReader in_Renamed) : base(in_Renamed)
- {
- }
-
- /// <summary>Collects only characters which satisfy
- /// {@link Character#isLetter(char)}.
- /// </summary>
- protected internal override char Normalize(char c)
- {
- return System.Char.ToLower(c);
- }
- }
- }