beagled/Lucene.Net/Analysis/PerFieldAnalyzerWrapper.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> This analyzer is used to facilitate scenarios where different
  21         /// fields require different analysis techniques.  Use {@link #addAnalyzer}
  22         /// to add a non-default analyzer on a Field name basis.
  23         /// See TestPerFieldAnalyzerWrapper.java for example usage.
  24         /// </summary>
  25         public class PerFieldAnalyzerWrapper:Analyzer
  26         {
  27                 private Analyzer defaultAnalyzer;
  28                 private System.Collections.IDictionary analyzerMap = new System.Collections.Hashtable();
  29
  30
  31                 /// <summary> Constructs with default analyzer.
  32                 ///
  33                 /// </summary>
  34                 /// <param name="defaultAnalyzer">Any fields not specifically
  35                 /// defined to use a different analyzer will use the one provided here.
  36                 /// </param>
  37                 public PerFieldAnalyzerWrapper(Analyzer defaultAnalyzer)
  38                 {
  39                         this.defaultAnalyzer = defaultAnalyzer;
  40                 }
  41
  42                 /// <summary> Defines an analyzer to use for the specified Field.
  43                 ///
  44                 /// </summary>
  45                 /// <param name="fieldName">Field name requiring a non-default analyzer.
  46                 /// </param>
  47                 /// <param name="analyzer">non-default analyzer to use for Field
  48                 /// </param>
  49                 public virtual void  AddAnalyzer(System.String fieldName, Analyzer analyzer)
  50                 {
  51                         analyzerMap[fieldName] = analyzer;
  52                 }
  53
  54                 public override TokenStream TokenStream(System.String fieldName, System.IO.TextReader reader)
  55                 {
  56                         Analyzer analyzer = (Analyzer) analyzerMap[fieldName];
  57                         if (analyzer == null)
  58                         {
  59                                 analyzer = defaultAnalyzer;
  60                         }
  61
  62                         return analyzer.TokenStream(fieldName, reader);
  63                 }
  64         }
  65 }