/*
* 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.search.highlight;
import java.io.IOException;
import org.apache.lucene.analysis.TokenFilter;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
/**
* This TokenFilter limits the number of tokens while indexing by adding up the
* current offset.
*/
public final class OffsetLimitTokenFilter extends TokenFilter {
private int offsetCount;
private OffsetAttribute offsetAttrib = getAttribute(OffsetAttribute.class);
private int offsetLimit;
public OffsetLimitTokenFilter(TokenStream input, int offsetLimit) {
super(input);
this.offsetLimit = offsetLimit;
}
@Override
public boolean incrementToken() throws IOException {
if (offsetCount < offsetLimit && input.incrementToken()) {
int offsetLength = offsetAttrib.endOffset() - offsetAttrib.startOffset();
offsetCount += offsetLength;
return true;
}
return false;
}
@Override
public void reset() throws IOException {
super.reset();
offsetCount = 0;
}
}