www.pudn.com > dlucene-1.4.3-src.rar > RussianLowerCaseFilter.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 org.apache.lucene.analysis.TokenFilter; 
import org.apache.lucene.analysis.Token; 
import org.apache.lucene.analysis.TokenStream; 
 
/** 
 * Normalizes token text to lower case, analyzing given ("russian") charset. 
 * 
 * @author  Boris Okner, b.okner@rogers.com 
 * @version $Id: RussianLowerCaseFilter.java,v 1.4 2004/03/29 22:48:01 cutting Exp $ 
 */ 
public final class RussianLowerCaseFilter extends TokenFilter 
{ 
    char[] charset; 
 
    public RussianLowerCaseFilter(TokenStream in, char[] charset) 
    { 
        super(in); 
        this.charset = charset; 
    } 
 
    public final Token next() throws java.io.IOException 
    { 
        Token t = input.next(); 
 
        if (t == null) 
            return null; 
 
        String txt = t.termText(); 
 
        char[] chArray = txt.toCharArray(); 
        for (int i = 0; i < chArray.length; i++) 
        { 
            chArray[i] = RussianCharsets.toLowerCase(chArray[i], charset); 
        } 
 
        String newTxt = new String(chArray); 
        // create new token 
        Token newToken = new Token(newTxt, t.startOffset(), t.endOffset()); 
 
        return newToken; 
    } 
}