beagled/Lucene.Net/Analysis/LowerCaseTokenizer.cs

   1 /*
   2  * Copyright 2004 The Apache Software Foundation
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 using System;
  18
  19 namespace Lucene.Net.Analysis
  20 {
  21
  22         /// <summary> LowerCaseTokenizer performs the function of LetterTokenizer
  23         /// and LowerCaseFilter together.  It divides text at non-letters and converts
  24         /// them to lower case.  While it is functionally equivalent to the combination
  25         /// of LetterTokenizer and LowerCaseFilter, there is a performance advantage
  26         /// to doing the two tasks at once, hence this (redundant) implementation.
  27         /// <P>
  28         /// Note: this does a decent job for most European languages, but does a terrible
  29         /// job for some Asian languages, where words are not separated by spaces.
  30         /// </summary>
  31         public sealed class LowerCaseTokenizer : LetterTokenizer
  32         {
  33                 /// <summary>Construct a new LowerCaseTokenizer. </summary>
  34                 public LowerCaseTokenizer(System.IO.TextReader in_Renamed) : base(in_Renamed)
  35                 {
  36                 }
  37
  38                 /// <summary>Collects only characters which satisfy
  39                 /// {@link Character#isLetter(char)}.
  40                 /// </summary>
  41                 protected internal override char Normalize(char c)
  42                 {
  43                         return System.Char.ToLower(c);
  44                 }
  45         }
  46 }