package org.apache.lucene.analysis.th;

/**
 * Copyright 2006 The Apache Software Foundation
 *
 * Licensed 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.Reader;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.core.LowerCaseFilter;
import org.apache.lucene.analysis.core.StopAnalyzer;
import org.apache.lucene.analysis.core.StopFilter;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.analysis.standard.StandardFilter;
import org.apache.lucene.analysis.standard.StandardTokenizer;
import org.apache.lucene.analysis.util.ReusableAnalyzerBase;
import org.apache.lucene.util.Version;

/**
 * {@link Analyzer} for Thai language. It uses {@link java.text.BreakIterator} to break words.
 * @version 0.2
 *
 * <p><b>NOTE</b>: This class uses the same {@link Version}
 * dependent settings as {@link StandardAnalyzer}.</p>
 */
public final class ThaiAnalyzer extends ReusableAnalyzerBase {
  private final Version matchVersion;

  public ThaiAnalyzer(Version matchVersion) {
    this.matchVersion = matchVersion;
  }

  /**
   * Creates
   * {@link org.apache.lucene.analysis.util.ReusableAnalyzerBase.TokenStreamComponents}
   * used to tokenize all the text in the provided {@link Reader}.
   * 
   * @return {@link org.apache.lucene.analysis.util.ReusableAnalyzerBase.TokenStreamComponents}
   *         built from a {@link StandardTokenizer} filtered with
   *         {@link StandardFilter}, {@link LowerCaseFilter}, {@link ThaiWordFilter}, and
   *         {@link StopFilter}
   */
  @Override
  protected TokenStreamComponents createComponents(String fieldName,
      Reader reader) {
    final Tokenizer source = new StandardTokenizer(matchVersion, reader);
    TokenStream result = new StandardFilter(source);
    if (matchVersion.onOrAfter(Version.LUCENE_31))
      result = new LowerCaseFilter(matchVersion, result);
    result = new ThaiWordFilter(matchVersion, result);
    return new TokenStreamComponents(source, new StopFilter(matchVersion,
        result, StopAnalyzer.ENGLISH_STOP_WORDS_SET));
  }
}