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.CharTokenizer;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.util.AttributeSource;
import org.apache.lucene.util.Version;
/**
* 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>
* <p>
* <a name="version"/>
* You must specify the required {@link Version} compatibility when creating
* {@link LetterTokenizer}:
* <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 class LetterTokenizer extends CharTokenizer {
/**
* Construct a new LetterTokenizer.
*
* @param matchVersion
* Lucene version to match See {@link <a href="#version">above</a>}
* @param in
* the input to split up into tokens
*/
public LetterTokenizer(Version matchVersion, Reader in) {
super(matchVersion, in);
}
/**
* Construct a new LetterTokenizer 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 LetterTokenizer(Version matchVersion, AttributeSource source, Reader in) {
super(matchVersion, source, in);
}
/**
* Construct a new LetterTokenizer 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 LetterTokenizer(Version matchVersion, AttributeFactory factory, Reader in) {
super(matchVersion, factory, in);
}
/**
* Construct a new LetterTokenizer.
*
* @deprecated use {@link #LetterTokenizer(Version, Reader)} instead. This
* will be removed in Lucene 4.0.
*/
public LetterTokenizer(Reader in) {
super(Version.LUCENE_30, in);
}
/**
* Construct a new LetterTokenizer using a given {@link AttributeSource}.
* @deprecated
* use {@link #LetterTokenizer(Version, AttributeSource, Reader)} instead.
* This will be removed in Lucene 4.0.
*/
public LetterTokenizer(AttributeSource source, Reader in) {
super(Version.LUCENE_30, source, in);
}
/**
* Construct a new LetterTokenizer using a given
* {@link org.apache.lucene.util.AttributeSource.AttributeFactory}.
*
* @deprecated use {@link #LetterTokenizer(Version, AttributeSource.AttributeFactory, Reader)}
* instead. This will be removed in Lucene 4.0.
*/
public LetterTokenizer(AttributeFactory factory, Reader in) {
super(Version.LUCENE_30, factory, in);
}
/** Collects only characters which satisfy
* {@link Character#isLetter(int)}.*/
@Override
protected boolean isTokenChar(int c) {
return Character.isLetter(c);
}
}