/*
* 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.facet;
import org.apache.lucene.search.CollectorManager;
import java.io.IOException;
import java.util.Collection;
import java.util.List;
/**
* A {@link CollectorManager} implementation which produces FacetsCollector and produces a merged FacetsCollector.
* This is used for concurrent FacetsCollection.
*/
public class FacetsCollectorManager implements CollectorManager<FacetsCollector, FacetsCollector> {
/** Sole constructor. */
public FacetsCollectorManager() {
}
@Override
public FacetsCollector newCollector() throws IOException {
return new FacetsCollector();
}
@Override
public FacetsCollector reduce(Collection<FacetsCollector> collectors) throws IOException {
if (collectors == null || collectors.size() == 0) {
return new FacetsCollector();
} if (collectors.size() == 1) {
return collectors.iterator().next();
}
return new ReducedFacetsCollector(collectors);
}
private static class ReducedFacetsCollector extends FacetsCollector {
public ReducedFacetsCollector(final Collection<FacetsCollector> facetsCollectors) {
final List<MatchingDocs> matchingDocs = this.getMatchingDocs();
facetsCollectors.forEach(facetsCollector -> matchingDocs.addAll(facetsCollector.getMatchingDocs()));
}
}
}