package org.apache.maven.index.context;

 /*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you 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.

  */

 import java.io.IOException;

 import java.io.Reader;

 import org.apache.lucene.analysis.Analyzer;

 import org.apache.lucene.analysis.CharTokenizer;

 import org.apache.lucene.analysis.TokenStream;

 import org.apache.lucene.analysis.standard.StandardAnalyzer;

 import org.apache.lucene.util.Version;

 import org.apache.maven.index.ArtifactInfo;

 /**

  * A Nexus specific <a

  * href="http://lucene.apache.org/java/2_4_0/api/core/org/apache/lucene/analysis/Analyzer.html">Lucene Analyzer</a> used

  * to produce legacy index transfer format

  * 

  * @author Jason van Zyl

  */

 public final class NexusLegacyAnalyzer

     extends Analyzer

 {

     private static Analyzer DEFAULT_ANALYZER = new StandardAnalyzer( Version.LUCENE_30 );

     @Override

     public TokenStream tokenStream( String field, final Reader reader )

     {

         if ( !isTextField( field ) )

         {

             return new CharTokenizer( reader )

             {

                 @Override

                 protected boolean isTokenChar( char c )

                 {

                     return Character.isLetterOrDigit( c );

                 }

                 @Override

                 protected char normalize( char c )

                 {

                     return Character.toLowerCase( c );

                 }

             };

         }

         else

         {

             return DEFAULT_ANALYZER.tokenStream( field, reader );

         }

     }

     @Override

     public TokenStream reusableTokenStream( String field, Reader reader )

         throws IOException

     {

         if ( !isTextField( field ) )

         {

             return new CharTokenizer( reader )

             {

                 @Override

                 protected boolean isTokenChar( char c )

                 {

                     return Character.isLetterOrDigit( c );

                 }

                 @Override

                 protected char normalize( char c )

                 {

                     return Character.toLowerCase( c );

                 }

             };

         }

         else

         {

             return DEFAULT_ANALYZER.reusableTokenStream( field, reader );

         }

     }

     protected boolean isTextField( String field )

     {

         return ArtifactInfo.NAME.equals( field ) || ArtifactInfo.DESCRIPTION.equals( field )

             || ArtifactInfo.NAMES.equals( field );

     }

 }