gaobinlong commented on code in PR #15936: URL: https://github.com/apache/lucene/pull/15936#discussion_r3367565152
########## lucene/grouping/src/java/org/apache/lucene/search/grouping/BlockGroupingCollectorManager.java: ########## @@ -0,0 +1,157 @@ +/* + * 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.grouping; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.Collection; +import java.util.List; +import org.apache.lucene.search.CollectorManager; +import org.apache.lucene.search.Sort; +import org.apache.lucene.search.Weight; + +/** + * A {@link CollectorManager} for {@link BlockGroupingCollector} that merges results from multiple + * collectors into a single {@link TopGroups}. This is intended for use with concurrent search, + * where each slice is searched by a separate {@link BlockGroupingCollector}. + * + * <p>Documents must be indexed as blocks using {@link + * org.apache.lucene.index.IndexWriter#addDocuments IndexWriter.addDocuments()} or {@link + * org.apache.lucene.index.IndexWriter#updateDocuments IndexWriter.updateDocuments()}. + * + * <p><b>NOTE</b>: All documents in a group block must be processed by the same {@link + * BlockGroupingCollector} instance. This means that the {@link + * org.apache.lucene.search.IndexSearcher}'s slices must not split a segment in a way that places + * documents from the same block into different slices. The default {@link + * org.apache.lucene.search.IndexSearcher#slices} implementation (inter-segment only) satisfies this + * constraint. If intra-segment concurrency is desired, the caller must override {@link + * org.apache.lucene.search.IndexSearcher#slices} to ensure each doc block falls entirely within one + * slice. + * + * <p>See {@link BlockGroupingCollector} for more details. + * + * <p>Example usage: + * + * <pre class="prettyprint"> + * IndexSearcher searcher = ...; // your IndexSearcher + * Query lastDocPerGroupQuery = new TermQuery(new Term("groupEnd", "true")); + * Weight lastDocPerGroup = searcher.createWeight( + * searcher.rewrite(lastDocPerGroupQuery), ScoreMode.COMPLETE_NO_SCORES, 1); + * + * BlockGroupingCollectorManager<BytesRef> manager = new BlockGroupingCollectorManager<>( + * Sort.RELEVANCE, // groupSort + * 0, // groupOffset + * 10, // topNGroups + * true, // needsScores + * lastDocPerGroup, + * Sort.RELEVANCE, // withinGroupSort + * 0, // withinGroupOffset + * 5); // maxDocsPerGroup + * + * TopGroups<BytesRef> result = searcher.search(query, manager); + * </pre> + * + * @lucene.experimental + */ +public class BlockGroupingCollectorManager<T> + implements CollectorManager<BlockGroupingCollector, TopGroups<T>> { + + private final Sort groupSort; + private final int groupOffset; + private final int topNGroups; + private final boolean needsScores; + private final Weight lastDocPerGroup; + + private final Sort withinGroupSort; + private final int withinGroupOffset; + private final int maxDocsPerGroup; + + /** + * Creates a new BlockGroupingCollectorManager. + * + * @param groupSort the sort used to rank groups + * @param groupOffset the offset into the groups to start returning from + * @param topNGroups the number of top groups to collect + * @param needsScores whether scores are needed (must be true if groupSort or withinGroupSort uses + * scores) + * @param lastDocPerGroup a {@link Weight} that matches the last document in each group block + * @param withinGroupSort the sort used to rank documents within each group + * @param withinGroupOffset the offset into each group's documents to start returning from + * @param maxDocsPerGroup the maximum number of documents to return per group + */ + public BlockGroupingCollectorManager( + Sort groupSort, + int groupOffset, + int topNGroups, + boolean needsScores, + Weight lastDocPerGroup, + Sort withinGroupSort, + int withinGroupOffset, + int maxDocsPerGroup) { + if (groupOffset < 0) { + throw new IllegalArgumentException("groupOffset must be >= 0 (got " + groupOffset + ")"); + } + + if (topNGroups < 1) { + throw new IllegalArgumentException("topNGroups must be >= 1 (got " + topNGroups + ")"); + } + + if (withinGroupOffset < 0) { + throw new IllegalArgumentException( + "withinGroupOffset must be >= 0 (got " + withinGroupOffset + ")"); + } + + if (maxDocsPerGroup < 1) { + throw new IllegalArgumentException( + "maxDocsPerGroup must be >= 1 (got " + maxDocsPerGroup + ")"); + } + + if (withinGroupSort.getSort().length == 0) { Review Comment: Added, thanks! -- This is an automated message from the Apache Git Service. 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