| using Lucene.Net.Index; |
| using Lucene.Net.Util; |
| using System.IO; |
| |
| namespace Lucene.Net.Search.Grouping.Terms |
| { |
| /* |
| * 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. |
| */ |
| |
| /// <summary> |
| /// Concrete implementation of <see cref="AbstractFirstPassGroupingCollector{BytesRef}"/> that groups based on |
| /// field values and more specifically uses <see cref="SortedDocValues"/> |
| /// to collect groups. |
| /// |
| /// @lucene.experimental |
| /// </summary> |
| public class TermFirstPassGroupingCollector : AbstractFirstPassGroupingCollector<BytesRef> |
| { |
| private readonly BytesRef scratchBytesRef = new BytesRef(); |
| private SortedDocValues index; |
| |
| private readonly string groupField; // LUCENENET: marked readonly |
| |
| /// <summary> |
| /// Create the first pass collector. |
| /// </summary> |
| /// <param name="groupField"> |
| /// The field used to group |
| /// documents. This field must be single-valued and |
| /// indexed (<see cref="FieldCache"/> is used to access its value |
| /// per-document). |
| /// </param> |
| /// <param name="groupSort"> |
| /// The <see cref="Sort"/> used to sort the |
| /// groups. The top sorted document within each group |
| /// according to groupSort, determines how that group |
| /// sorts against other groups. This must be non-null, |
| /// ie, if you want to groupSort by relevance use |
| /// <see cref="Sort.RELEVANCE"/>. |
| /// </param> |
| /// <param name="topNGroups"> |
| /// How many top groups to keep. |
| /// </param> |
| /// <exception cref="IOException">When I/O related errors occur</exception> |
| public TermFirstPassGroupingCollector(string groupField, Sort groupSort, int topNGroups) |
| : base(groupSort, topNGroups) |
| { |
| this.groupField = groupField; |
| } |
| |
| protected override BytesRef GetDocGroupValue(int doc) |
| { |
| int ord = index.GetOrd(doc); |
| if (ord == -1) |
| { |
| return null; |
| } |
| else |
| { |
| index.LookupOrd(ord, scratchBytesRef); |
| return scratchBytesRef; |
| } |
| } |
| |
| protected override BytesRef CopyDocGroupValue(BytesRef groupValue, BytesRef reuse) |
| { |
| if (groupValue == null) |
| { |
| return null; |
| } |
| else if (reuse != null) |
| { |
| reuse.CopyBytes(groupValue); |
| return reuse; |
| } |
| else |
| { |
| return BytesRef.DeepCopyOf(groupValue); |
| } |
| } |
| |
| public override void SetNextReader(AtomicReaderContext context) |
| { |
| base.SetNextReader(context); |
| index = FieldCache.DEFAULT.GetTermsIndex(context.AtomicReader, groupField); |
| } |
| } |
| } |