/*
* 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.lucene.analysis.miscellaneous;
import org.apache.lucene.analysis.CharArraySet;
import org.apache.lucene.analysis.FilteringTokenFilter;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
/**
* A TokenFilter that only keeps tokens with text contained in the
* required words. This filter behaves like the inverse of StopFilter.
*
* @since solr 1.3
*/
public final class KeepWordFilter extends FilteringTokenFilter {
private final CharArraySet words;
private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
/**
* Create a new {@link KeepWordFilter}.
* <p><b>NOTE</b>: The words set passed to this constructor will be directly
* used by this filter and should not be modified.
* @param in the {@link TokenStream} to consume
* @param words the words to keep
*/
public KeepWordFilter(TokenStream in, CharArraySet words) {
super(in);
this.words = words;
}
@Override
public boolean accept() {
return words.contains(termAtt.buffer(), 0, termAtt.length());
}
}