org.elasticsearch.search.fetch.subphase.FetchFieldsPhase Maven / Gradle / Ivy
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/*
* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
* or more contributor license agreements. Licensed under the Elastic License
* 2.0 and the Server Side Public License, v 1; you may not use this file except
* in compliance with, at your election, the Elastic License 2.0 or the Server
* Side Public License, v 1.
*/
package org.elasticsearch.search.fetch.subphase;
import org.apache.lucene.index.LeafReaderContext;
import org.elasticsearch.common.document.DocumentField;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.fetch.FetchContext;
import org.elasticsearch.search.fetch.FetchSubPhase;
import org.elasticsearch.search.fetch.FetchSubPhaseProcessor;
import org.elasticsearch.search.lookup.SourceLookup;
import java.io.IOException;
import java.util.Map;
/**
* A fetch sub-phase for high-level field retrieval. Given a list of fields, it
* retrieves the field values through the relevant {@link org.elasticsearch.index.mapper.ValueFetcher}
* and returns them as document fields.
*/
public final class FetchFieldsPhase implements FetchSubPhase {
@Override
public FetchSubPhaseProcessor getProcessor(FetchContext fetchContext) {
FetchFieldsContext fetchFieldsContext = fetchContext.fetchFieldsContext();
if (fetchFieldsContext == null) {
return null;
}
FieldFetcher fieldFetcher = FieldFetcher.create(fetchContext.getSearchExecutionContext(), fetchFieldsContext.fields());
return new FetchSubPhaseProcessor() {
@Override
public void setNextReader(LeafReaderContext readerContext) {
fieldFetcher.setNextReader(readerContext);
}
@Override
public void process(HitContext hitContext) throws IOException {
SearchHit hit = hitContext.hit();
SourceLookup sourceLookup = hitContext.sourceLookup();
Map documentFields = fieldFetcher.fetch(sourceLookup);
for (Map.Entry entry : documentFields.entrySet()) {
hit.setDocumentField(entry.getKey(), entry.getValue());
}
}
};
}
}