/**
* 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.
*/
package org.apache.solr.analysis;
import org.apache.lucene.analysis.TokenFilter;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.Token;
import org.apache.lucene.analysis.CharArraySet;
import java.io.IOException;
import java.util.Set;
/**
* A TokenFilter that only keeps tokens with text contained in the
* required words. This filter behaves like the inverse of StopFilter.
*
* @version $Id: KeepWordFilter.java 643465 2008-04-01 16:10:19Z gsingers $
* @since solr 1.3
*/
public final class KeepWordFilter extends TokenFilter {
final CharArraySet words;
public KeepWordFilter(TokenStream in, Set<String> words, boolean ignoreCase ) {
super(in);
this.words = new CharArraySet(words, ignoreCase);
}
@Override
public final Token next(Token in) throws IOException {
for (Token token=input.next(in); token!=null; token=input.next()) {
if( words.contains( token.termBuffer(), 0, token.termLength() ) ) {
return token;
}
}
return null;
}
}