package org.apache.lucene.analysis;/** * 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;/** A LetterTokenizer is a tokenizer that divides text at non-letters.  That's  to say, it defines tokens as maximal strings of adjacent letters, as defined  by java.lang.Character.isLetter() predicate.  Note: this does a decent job for most European languages, but does a terrible  job for some Asian languages, where words are not separated by spaces. */public class LetterTokenizer extends CharTokenizer {  /** Construct a new LetterTokenizer. */  public LetterTokenizer(Reader in) {    super(in);  }  /** Collects only characters which satisfy   * {@link Character#isLetter(char)}.*/  protected boolean isTokenChar(char c) {    return Character.isLetter(c);  }}