| /* |
| * 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 java.io.IOException; |
| import java.util.List; |
| import org.apache.lucene.index.DocValues; |
| import org.apache.lucene.index.IndexReader; |
| import org.apache.lucene.index.LeafReaderContext; |
| import org.apache.lucene.index.OrdinalMap; |
| import org.apache.lucene.index.SortedSetDocValues; |
| import org.apache.lucene.util.packed.PackedInts; |
| |
| /** |
| * Stores an {@link OrdinalMap} created for a specific {@link IndexReader} ({@code reader}) + {@code |
| * field}. Enables re-use of the {@code ordinalMap} once created since creation is costly. |
| * |
| * <p>Note: It's important that callers confirm the ordinal map is still valid for their cases. |
| * Specifically, callers should confirm that the reader used to create the map ({@code reader}) |
| * matches their use-case. |
| */ |
| public class StringDocValuesReaderState { |
| |
| final IndexReader reader; |
| final String field; |
| final OrdinalMap ordinalMap; |
| |
| /** |
| * Construct state specific to a reader + field. This builds an {@link OrdinalMap} that can be |
| * reused for mapping segment-specific ordinals to global ordinals for the given field. Keep in |
| * mind that the state is only valid for the specified {@link IndexReader}, so opening new readers |
| * (e.g., to pickup NRT updates) requires constructing a new state instance. |
| */ |
| public StringDocValuesReaderState(IndexReader reader, String field) throws IOException { |
| this.reader = reader; |
| this.field = field; |
| ordinalMap = buildOrdinalMap(reader, field); |
| } |
| |
| private static OrdinalMap buildOrdinalMap(IndexReader reader, String field) throws IOException { |
| List<LeafReaderContext> leaves = reader.leaves(); |
| int leafCount = leaves.size(); |
| |
| if (leafCount <= 1) { |
| return null; |
| } |
| |
| SortedSetDocValues[] docValues = new SortedSetDocValues[leafCount]; |
| for (int i = 0; i < leafCount; i++) { |
| LeafReaderContext context = reader.leaves().get(i); |
| docValues[i] = DocValues.getSortedSet(context.reader(), field); |
| } |
| |
| IndexReader.CacheHelper cacheHelper = reader.getReaderCacheHelper(); |
| IndexReader.CacheKey owner = cacheHelper == null ? null : cacheHelper.getKey(); |
| |
| return OrdinalMap.build(owner, docValues, PackedInts.DEFAULT); |
| } |
| |
| @Override |
| public String toString() { |
| return "StringDocValuesReaderState(field=" + field + " reader=" + reader + ")"; |
| } |
| } |