org.apache.solr.search.grouping.Command 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.solr.search.grouping;
import org.apache.lucene.search.Collector;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Sort;
import java.io.IOException;
import java.util.List;
/**
* Defines a grouping command.
* This is an abstraction on how the {@link Collector} instances are created
* and how the results are retrieved from the {@link Collector} instances.
*
* @lucene.experimental
*/
public interface Command {
/**
* Returns a list of {@link Collector} instances to be
* included in the search based on the .
*
* @return a list of {@link Collector} instances
* @throws IOException If I/O related errors occur
*/
List create() throws IOException;
/**
* Run post-collection steps.
* @throws IOException If I/O related errors occur
*/
default void postCollect(IndexSearcher searcher) throws IOException {}
/**
* Returns the results that the collectors created
* by {@link #create()} contain after a search has been executed.
*
* @return The results of the collectors
*/
T result() throws IOException;
/**
* @return The key of this command to uniquely identify itself
*/
String getKey();
/**
* @return The group sort (overall sort)
*/
Sort getGroupSort();
/**
* @return The sort inside a group
*/
Sort getWithinGroupSort();
}