www.pudn.com > dlucene-1.4.3-src.rar > RussianLetterTokenizer.java

package org.apache.lucene.analysis.ru; 
 
/** 
 * Copyright 2004 The Apache Software Foundation 
 * 
 * Licensed 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; 
 
/** 
 * A RussianLetterTokenizer is a tokenizer that extends LetterTokenizer by additionally looking up letters 
 * in a given "russian charset". The problem with LeterTokenizer is that it uses Character.isLetter() method, 
 * which doesn't know how to detect letters in encodings like CP1252 and KOI8 
 * (well-known problems with 0xD7 and 0xF7 chars) 
 * 
 * @author  Boris Okner, b.okner@rogers.com 
 * @version $Id: RussianLetterTokenizer.java,v 1.3 2004/03/29 22:48:01 cutting Exp $ 
 */ 
 
public class RussianLetterTokenizer extends CharTokenizer 
{ 
    /** Construct a new LetterTokenizer. */ 
    private char[] charset; 
 
    public RussianLetterTokenizer(Reader in, char[] charset) 
    { 
        super(in); 
        this.charset = charset; 
    } 
 
    /** 
     * Collects only characters which satisfy 
     * {@link Character#isLetter(char)}. 
     */ 
    protected boolean isTokenChar(char c) 
    { 
        if (Character.isLetter(c)) 
            return true; 
        for (int i = 0; i < charset.length; i++) 
        { 
            if (c == charset[i]) 
                return true; 
        } 
        return false; 
    } 
}