| package org.apache.lucene.analysis.core; |
| |
| /* |
| * 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.Tokenizer; |
| import org.apache.lucene.analysis.util.CharTokenizer; |
| import org.apache.lucene.util.AttributeFactory; |
| import org.apache.lucene.util.Version; |
| |
| /** |
| * LowerCaseTokenizer performs the function of LetterTokenizer |
| * and LowerCaseFilter together. It divides text at non-letters and converts |
| * them to lower case. While it is functionally equivalent to the combination |
| * of LetterTokenizer and LowerCaseFilter, there is a performance advantage |
| * to doing the two tasks at once, hence this (redundant) implementation. |
| * <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> |
| * <p> |
| * <a name="version"/> |
| * You may specify the required {@link Version} compatibility when creating |
| * {@link LowerCaseTokenizer}: |
| * <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> |
| * </p> |
| */ |
| public final class LowerCaseTokenizer extends LetterTokenizer { |
| |
| /** |
| * Construct a new LowerCaseTokenizer. |
| * @param in |
| * the input to split up into tokens |
| */ |
| public LowerCaseTokenizer(Reader in) { |
| super(in); |
| } |
| |
| /** |
| * @deprecated Use {@link #LowerCaseTokenizer(Reader)} |
| */ |
| @Deprecated |
| public LowerCaseTokenizer(Version matchVersion, Reader in) { |
| super(matchVersion, in); |
| } |
| |
| /** |
| * Construct a new LowerCaseTokenizer using a given |
| * {@link org.apache.lucene.util.AttributeFactory}. |
| * |
| * @param factory |
| * the attribute factory to use for this {@link Tokenizer} |
| * @param in |
| * the input to split up into tokens |
| */ |
| public LowerCaseTokenizer(AttributeFactory factory, Reader in) { |
| super(factory, in); |
| } |
| |
| /** |
| * @deprecated Use {@link #LowerCaseTokenizer(AttributeFactory,Reader)} |
| */ |
| @Deprecated |
| public LowerCaseTokenizer(Version matchVersion, AttributeFactory factory, Reader in) { |
| super(matchVersion, factory, in); |
| } |
| |
| /** Converts char to lower case |
| * {@link Character#toLowerCase(int)}.*/ |
| @Override |
| protected int normalize(int c) { |
| return Character.toLowerCase(c); |
| } |
| } |