content: package org.apache.lucene.analysis.ru;
  
  /**
   * 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.Reader;
  import org.apache.lucene.analysis.CharTokenizer;
  import org.apache.lucene.analysis.Tokenizer; // for javadocs
  import org.apache.lucene.analysis.LetterTokenizer; // for javadocs
  import org.apache.lucene.analysis.standard.StandardTokenizer; // for javadocs
  import org.apache.lucene.util.AttributeSource;
  import org.apache.lucene.util.Version;
  
  /**
   * A RussianLetterTokenizer is a {@link Tokenizer} that extends {@link LetterTokenizer}
   * by also allowing the basic Latin digits 0-9.
   * <p>
   * <a name="version"/>
   * You must specify the required {@link Version} compatibility when creating
   * {@link RussianLetterTokenizer}:
   * <ul>
   * <li>As of 3.1, {@link CharTokenizer} uses an int based API to normalize and
   * detect token characters. See {@link CharTokenizer#isTokenChar(int)} and
   * {@link CharTokenizer#normalize(int)} for details.</li>
   * </ul>
   * @deprecated Use {@link StandardTokenizer} instead, which has the same functionality.
   * This filter will be removed in Lucene 5.0 
   */
  @Deprecated
  public class RussianLetterTokenizer extends CharTokenizer
  {    
      private static final int DIGIT_0 = '0';
      private static final int DIGIT_9 = '9';
      
      /**
       * Construct a new RussianLetterTokenizer. * @param matchVersion Lucene version
       * to match See {@link <a href="#version">above</a>}
       * 
       * @param in
       *          the input to split up into tokens
       */
      public RussianLetterTokenizer(Version matchVersion, Reader in) {
        super(matchVersion, in);
      }
  
      /**
       * Construct a new RussianLetterTokenizer using a given {@link AttributeSource}.
       * 
       * @param matchVersion
       *          Lucene version to match See {@link <a href="#version">above</a>}
       * @param source
       *          the attribute source to use for this {@link Tokenizer}
       * @param in
       *          the input to split up into tokens
       */
      public RussianLetterTokenizer(Version matchVersion, AttributeSource source, Reader in) {
        super(matchVersion, source, in);
      }
  
      /**
       * Construct a new RussianLetterTokenizer using a given
       * {@link org.apache.lucene.util.AttributeSource.AttributeFactory}. * @param
       * matchVersion Lucene version to match See
       * {@link <a href="#version">above</a>}
       * 
       * @param factory
       *          the attribute factory to use for this {@link Tokenizer}
       * @param in
       *          the input to split up into tokens
       */
      public RussianLetterTokenizer(Version matchVersion, AttributeFactory factory, Reader in) {
        super(matchVersion, factory, in);
      }
      
      /**
       * Construct a new RussianLetterTokenizer.
       * 
       * @deprecated use {@link #RussianLetterTokenizer(Version, Reader)} instead. This will
       *             be removed in Lucene 4.0.
       */
      @Deprecated
      public RussianLetterTokenizer(Reader in) {
        super(in);
      }
  
      /**
       * Construct a new RussianLetterTokenizer using a given {@link AttributeSource}.
       * 
       * @deprecated use {@link #RussianLetterTokenizer(Version, AttributeSource, Reader)}
       *             instead. This will be removed in Lucene 4.0.
       */
      @Deprecated
      public RussianLetterTokenizer(AttributeSource source, Reader in) {
        super(source, in);
      }
  
      /**
       * Construct a new RussianLetterTokenizer using a given
       * {@link org.apache.lucene.util.AttributeSource.AttributeFactory}.
       * 
       * @deprecated use {@link #RussianLetterTokenizer(Version, AttributeSource.AttributeFactory, Reader)}
       *             instead. This will be removed in Lucene 4.0.
       */
      @Deprecated
      public RussianLetterTokenizer(AttributeFactory factory, Reader in) {
        super(factory, in);
      }
      
      
      /**
       * Collects only characters which satisfy
       * {@link Character#isLetter(int)}.
       */
      @Override
      protected boolean isTokenChar(int c) {
          return Character.isLetter(c) || (c >= DIGIT_0 && c <= DIGIT_9);
      }
  }
  