org.apache.lucene.search.uhighlight.MultiFieldsOffsetStrategy Maven / Gradle / Ivy
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/*
* 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.uhighlight;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.lucene.index.LeafReader;
/**
* FieldOffsetStrategy that combines offsets from multiple fields. Used to highlight a single field
* based on matches from multiple fields.
*
* @lucene.internal
*/
public class MultiFieldsOffsetStrategy extends FieldOffsetStrategy {
private final List fieldsOffsetStrategies;
public MultiFieldsOffsetStrategy(List fieldsOffsetStrategies) {
super(null);
this.fieldsOffsetStrategies = fieldsOffsetStrategies;
}
@Override
public String getField() {
throw new IllegalStateException("MultiFieldsOffsetStrategy does not have a single field.");
}
@Override
public UnifiedHighlighter.OffsetSource getOffsetSource() {
// TODO: what should be returned here as offset source?
return fieldsOffsetStrategies.get(0).getOffsetSource();
}
@Override
public OffsetsEnum getOffsetsEnum(LeafReader reader, int docId, String content)
throws IOException {
List fieldsOffsetsEnums = new ArrayList<>(fieldsOffsetStrategies.size());
for (FieldOffsetStrategy fieldOffsetStrategy : fieldsOffsetStrategies) {
OffsetsEnum offsetsEnum = fieldOffsetStrategy.getOffsetsEnum(reader, docId, content);
if (offsetsEnum != OffsetsEnum.EMPTY) {
fieldsOffsetsEnums.add(offsetsEnum);
}
}
return new OffsetsEnum.MultiOffsetsEnum(fieldsOffsetsEnums);
}
}