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 using System;
  17 namespace Lucene.Net.Analysis
  18 {
  19
  20         /// <summary> LowerCaseTokenizer performs the function of LetterTokenizer
  21         /// and LowerCaseFilter together.  It divides text at non-letters and converts
  22         /// them to lower case.  While it is functionally equivalent to the combination
  23         /// of LetterTokenizer and LowerCaseFilter, there is a performance advantage
  24         /// to doing the two tasks at once, hence this (redundant) implementation.
  25         /// <P>
  26         /// Note: this does a decent job for most European languages, but does a terrible
  27         /// job for some Asian languages, where words are not separated by spaces.
  28         /// </summary>
  29         public sealed class LowerCaseTokenizer : LetterTokenizer
  30         {
  31                 /// <summary>Construct a new LowerCaseTokenizer. </summary>
  32                 public LowerCaseTokenizer(System.IO.TextReader in_Renamed) : base(in_Renamed)
  33                 {
  34                 }
  35
  36                 /// <summary>Collects only characters which satisfy
  37                 /// {@link Character#isLetter(char)}.
  38                 /// </summary>
  39                 protected internal override char Normalize(char c)
  40                 {
  41                         return System.Char.ToLower(c);
  42                 }
  43         }
  44 }