/**

  * Distribution License:

  * JSword is free software; you can redistribute it and/or modify it under

  * the terms of the GNU Lesser General Public License, version 2.1 or later

  * as published by the Free Software Foundation. This program is distributed

  * in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even

  * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

  * See the GNU Lesser General Public License for more details.

  *

  * The License is available on the internet at:

  *      http://www.gnu.org/copyleft/lgpl.html

  * or by writing to:

  *      Free Software Foundation, Inc.

  *      59 Temple Place - Suite 330

  *      Boston, MA 02111-1307, USA

  *

  * © CrossWire Bible Society, 2009 - 2016

  *

  */

 package org.crosswire.jsword.index.lucene.analysis;

 import java.io.IOException;

 import java.io.Reader;

 import org.apache.lucene.analysis.LowerCaseFilter;

 import org.apache.lucene.analysis.StopFilter;

 import org.apache.lucene.analysis.TokenStream;

 import org.apache.lucene.analysis.ar.ArabicLetterTokenizer;

 import org.apache.lucene.analysis.ar.ArabicNormalizationFilter;

 import org.apache.lucene.analysis.fa.PersianAnalyzer;

 import org.apache.lucene.analysis.fa.PersianNormalizationFilter;

 import org.apache.lucene.util.Version;

 /**

  * An Analyzer whose {@link TokenStream} is built from a

  * {@link ArabicLetterTokenizer} filtered with {@link LowerCaseFilter},

  * {@link ArabicNormalizationFilter}, {@link PersianNormalizationFilter} and

  * Persian {@link StopFilter} (optional)

  * 

  * @see gnu.lgpl.License The GNU Lesser General Public License for details.

  * @author DM Smith

  */

 public class PersianLuceneAnalyzer extends AbstractBookAnalyzer {

     public PersianLuceneAnalyzer() {

         stopSet = PersianAnalyzer.getDefaultStopSet();

     }

     /*

      * (non-Javadoc)

      * 

      * @see org.apache.lucene.analysis.Analyzer#tokenStream(java.lang.String,

      * java.io.Reader)

      */

     @Override

     public final TokenStream tokenStream(String fieldName, Reader reader) {

         TokenStream result = new ArabicLetterTokenizer(reader);

         result = new LowerCaseFilter(result);

         result = new ArabicNormalizationFilter(result);

         /* additional persian-specific normalization */

         result = new PersianNormalizationFilter(result);

         /*

          * the order here is important: the stop set is normalized with the

          * above!

          */

         if (doStopWords && stopSet != null) {

             result = new StopFilter(StopFilter.getEnablePositionIncrementsVersionDefault(matchVersion), result, stopSet);

         }

         return result;

     }

     /**

      * Returns a (possibly reused) {@link TokenStream} which tokenizes all the

      * text in the provided {@link Reader}.

      * 

      * @return A {@link TokenStream} built from a {@link ArabicLetterTokenizer}

      *         filtered with {@link LowerCaseFilter},

      *         {@link ArabicNormalizationFilter},

      *         {@link PersianNormalizationFilter} and Persian Stop words

      */

     @Override

     public TokenStream reusableTokenStream(String fieldName, Reader reader) throws IOException {

         SavedStreams streams = (SavedStreams) getPreviousTokenStream();

         if (streams == null) {

             streams = new SavedStreams(new ArabicLetterTokenizer(reader));

             streams.setResult(new LowerCaseFilter(streams.getResult()));

             streams.setResult(new ArabicNormalizationFilter(streams.getResult()));

             /* additional persian-specific normalization */

             streams.setResult(new PersianNormalizationFilter(streams.getResult()));

             /*

              * the order here is important: the stop set is normalized with the

              * above!

              */

             if (doStopWords && stopSet != null) {

                 streams.setResult(new StopFilter(false, streams.getResult(), stopSet));

             }

             setPreviousTokenStream(streams);

         } else {

             streams.getSource().reset(reader);

         }

         return streams.getResult();

     }

     private final Version matchVersion = Version.LUCENE_29;

 }