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/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.join.fetch;
import org.apache.lucene.index.LeafReader;
import org.apache.lucene.index.SortedDocValues;
import org.apache.lucene.util.BytesRef;
import org.elasticsearch.ExceptionsHelper;
import org.elasticsearch.index.mapper.DocumentMapper;
import org.elasticsearch.join.mapper.ParentIdFieldMapper;
import org.elasticsearch.join.mapper.ParentJoinFieldMapper;
import org.elasticsearch.search.SearchHitField;
import org.elasticsearch.search.fetch.FetchSubPhase;
import org.elasticsearch.search.internal.SearchContext;
import java.io.IOException;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
/**
* A sub fetch phase that retrieves the join name and the parent id for each document containing
* a {@link ParentJoinFieldMapper} field.
*/
public final class ParentJoinFieldSubFetchPhase implements FetchSubPhase {
@Override
public void hitExecute(SearchContext context, HitContext hitContext) {
if (context.storedFieldsContext() != null && context.storedFieldsContext().fetchFields() == false) {
return;
}
ParentJoinFieldMapper mapper = ParentJoinFieldMapper.getMapper(context.mapperService());
if (mapper == null) {
// hit has no join field.
return;
}
String joinName = getSortedDocValue(mapper.name(), hitContext.reader(), hitContext.docId());
if (joinName == null) {
return;
}
// if the hit is a children we extract the parentId (if it's a parent we can use the _id field directly)
ParentIdFieldMapper parentMapper = mapper.getParentIdFieldMapper(joinName, false);
String parentId = null;
if (parentMapper != null) {
parentId = getSortedDocValue(parentMapper.name(), hitContext.reader(), hitContext.docId());
}
Map<String, SearchHitField> fields = hitContext.hit().fieldsOrNull();
if (fields == null) {
fields = new HashMap<>();
hitContext.hit().fields(fields);
}
fields.put(mapper.name(), new SearchHitField(mapper.name(), Collections.singletonList(joinName)));
if (parentId != null) {
fields.put(parentMapper.name(), new SearchHitField(parentMapper.name(), Collections.singletonList(parentId)));
}
}
private String getSortedDocValue(String field, LeafReader reader, int docId) {
try {
SortedDocValues docValues = reader.getSortedDocValues(field);
if (docValues == null || docValues.advanceExact(docId) == false) {
return null;
}
int ord = docValues.ordValue();
BytesRef joinName = docValues.lookupOrd(ord);
return joinName.utf8ToString();
} catch (IOException e) {
throw ExceptionsHelper.convertToElastic(e);
}
}
}
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