Lucene.Net/Analysis/LowerCaseFilter.cs

   1 using System;
   2
   3 namespace Lucene.Net.Analysis
   4 {
   5         /* ====================================================================
   6          * The Apache Software License, Version 1.1
   7          *
   8          * Copyright (c) 2001 The Apache Software Foundation.  All rights
   9          * reserved.
  10          *
  11          * Redistribution and use in source and binary forms, with or without
  12          * modification, are permitted provided that the following conditions
  13          * are met:
  14          *
  15          * 1. Redistributions of source code must retain the above copyright
  16          *    notice, this list of conditions and the following disclaimer.
  17          *
  18          * 2. Redistributions in binary form must reproduce the above copyright
  19          *    notice, this list of conditions and the following disclaimer in
  20          *    the documentation and/or other materials provided with the
  21          *    distribution.
  22          *
  23          * 3. The end-user documentation included with the redistribution,
  24          *    if any, must include the following acknowledgment:
  25          *       "This product includes software developed by the
  26          *        Apache Software Foundation (http://www.apache.org/)."
  27          *    Alternately, this acknowledgment may appear in the software itself,
  28          *    if and wherever such third-party acknowledgments normally appear.
  29          *
  30          * 4. The names "Apache" and "Apache Software Foundation" and
  31          *    "Apache Lucene" must not be used to endorse or promote products
  32          *    derived from this software without prior written permission. For
  33          *    written permission, please contact apache@apache.org.
  34          *
  35          * 5. Products derived from this software may not be called "Apache",
  36          *    "Apache Lucene", nor may "Apache" appear in their name, without
  37          *    prior written permission of the Apache Software Foundation.
  38          *
  39          * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
  40          * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  41          * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  42          * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
  43          * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  44          * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  45          * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  46          * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  47          * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  48          * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  49          * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  50          * SUCH DAMAGE.
  51          * ====================================================================
  52          *
  53          * This software consists of voluntary contributions made by many
  54          * individuals on behalf of the Apache Software Foundation.  For more
  55          * information on the Apache Software Foundation, please see
  56          * <http://www.apache.org/>.
  57          */
  58
  59         /// <summary>
  60         /// Normalizes token text to lower case.
  61         /// </summary>
  62         /// <version>$Id: LowerCaseFilter.cs,v 1.1.1.1 2004/04/29 22:53:51 trow Exp $</version>
  63         public sealed class LowerCaseFilter : TokenFilter
  64         {
  65                 public LowerCaseFilter(TokenStream _in) : base(_in)
  66                 {
  67                 }
  68
  69                 public override Token Next()
  70                 {
  71                         Token t = input.Next();
  72
  73                         if (t == null)
  74                                 return null;
  75
  76                         t.termText = t.termText.ToLower();
  77
  78                         return t;
  79                 }
  80         }
  81 }