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;
import org.apache.lucene.util.AttributeSource;
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 must 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 matchVersion
* Lucene version to match See {@link <a href="#version">above</a>}
*
* @param in
* the input to split up into tokens
*/
public LowerCaseTokenizer(Version matchVersion, Reader in) {
super(matchVersion, in);
}
/**
* Construct a new LowerCaseTokenizer 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 LowerCaseTokenizer(Version matchVersion, AttributeSource source, Reader in) {
super(matchVersion, source, in);
}
/**
* Construct a new LowerCaseTokenizer 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 LowerCaseTokenizer(Version matchVersion, AttributeFactory factory, Reader in) {
super(matchVersion, factory, in);
}
/**
* Construct a new LowerCaseTokenizer.
*
* @deprecated use {@link #LowerCaseTokenizer(Version, Reader)} instead. This will be
* removed in Lucene 4.0.
*/
@Deprecated
public LowerCaseTokenizer(Reader in) {
super(Version.LUCENE_30, in);
}
/**
* Construct a new LowerCaseTokenizer using a given {@link AttributeSource}.
*
* @deprecated use {@link #LowerCaseTokenizer(Version, AttributeSource, Reader)}
* instead. This will be removed in Lucene 4.0.
*/
@Deprecated
public LowerCaseTokenizer(AttributeSource source, Reader in) {
super(Version.LUCENE_30, source, in);
}
/**
* Construct a new LowerCaseTokenizer using a given
* {@link org.apache.lucene.util.AttributeSource.AttributeFactory}.
*
* @deprecated use {@link #LowerCaseTokenizer(Version, AttributeSource.AttributeFactory, Reader)}
* instead. This will be removed in Lucene 4.0.
*/
@Deprecated
public LowerCaseTokenizer(AttributeFactory factory, Reader in) {
super(Version.LUCENE_30, factory, in);
}
/** Converts char to lower case
* {@link Character#toLowerCase(int)}.*/
@Override
protected int normalize(int c) {
return Character.toLowerCase(c);
}
}