| /* |
| * 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<T> { |
| |
| /** |
| * 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<Collector> 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(); |
| |
| } |