/*
*
* 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.
*
*/
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using Lucene.Net.Analysis.Standard;
using Version=Lucene.Net.Util.Version;
namespace Lucene.Net.Analysis.Th
{
/**
* {@link Analyzer} for Thai language. It uses {@link java.text.BreakIterator} to break words.
* @version 0.2
*
*
NOTE: This class uses the same {@link Version}
* dependent settings as {@link StandardAnalyzer}.
*/
public class ThaiAnalyzer : Analyzer
{
private readonly Version matchVersion;
public ThaiAnalyzer(Version matchVersion)
{
SetOverridesTokenStreamMethod();
this.matchVersion = matchVersion;
}
public override TokenStream TokenStream(String fieldName, TextReader reader)
{
TokenStream ts = new StandardTokenizer(matchVersion, reader);
ts = new StandardFilter(ts);
ts = new ThaiWordFilter(ts);
ts = new StopFilter(StopFilter.GetEnablePositionIncrementsVersionDefault(matchVersion),
ts, StopAnalyzer.ENGLISH_STOP_WORDS_SET);
return ts;
}
private class SavedStreams
{
protected internal Tokenizer source;
protected internal TokenStream result;
};
public override TokenStream ReusableTokenStream(String fieldName, TextReader reader)
{
if (overridesTokenStreamMethod)
{
// LUCENE-1678: force fallback to tokenStream() if we
// have been subclassed and that subclass overrides
// tokenStream but not reusableTokenStream
return TokenStream(fieldName, reader);
}
SavedStreams streams = (SavedStreams)PreviousTokenStream;
if (streams == null)
{
streams = new SavedStreams();
streams.source = new StandardTokenizer(matchVersion, reader);
streams.result = new StandardFilter(streams.source);
streams.result = new ThaiWordFilter(streams.result);
streams.result = new StopFilter(StopFilter.GetEnablePositionIncrementsVersionDefault(matchVersion),
streams.result, StopAnalyzer.ENGLISH_STOP_WORDS_SET);
PreviousTokenStream = streams;
}
else
{
streams.source.Reset(reader);
streams.result.Reset(); // reset the ThaiWordFilter's state
}
return streams.result;
}
}
}