| /* |
| * 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. |
| */ |
| package org.apache.lucene.analysis.core; |
| |
| |
| import org.apache.lucene.analysis.Tokenizer; |
| import org.apache.lucene.analysis.util.CharTokenizer; |
| import org.apache.lucene.util.AttributeFactory; |
| |
| /** |
| * 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. |
| * <p> |
| * 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. |
| * </p> |
| */ |
| |
| public class LetterTokenizer extends CharTokenizer { |
| |
| /** |
| * Construct a new LetterTokenizer. |
| */ |
| public LetterTokenizer() { |
| } |
| |
| /** |
| * Construct a new LetterTokenizer using a given |
| * {@link org.apache.lucene.util.AttributeFactory}. |
| * |
| * @param factory |
| * the attribute factory to use for this {@link Tokenizer} |
| */ |
| public LetterTokenizer(AttributeFactory factory) { |
| super(factory); |
| } |
| |
| /** |
| * Construct a new LetterTokenizer using a given |
| * {@link org.apache.lucene.util.AttributeFactory}. |
| * |
| * @param factory the attribute factory to use for this {@link Tokenizer} |
| * @param maxTokenLen maximum token length the tokenizer will emit. |
| * Must be greater than 0 and less than MAX_TOKEN_LENGTH_LIMIT (1024*1024) |
| * @throws IllegalArgumentException if maxTokenLen is invalid. |
| |
| */ |
| public LetterTokenizer(AttributeFactory factory, int maxTokenLen) { |
| super(factory, maxTokenLen); |
| } |
| |
| /** Collects only characters which satisfy |
| * {@link Character#isLetter(int)}.*/ |
| @Override |
| protected boolean isTokenChar(int c) { |
| return Character.isLetter(c); |
| } |
| } |