Add parsing method for Top Hits aggregation (#24717)

Related to #23331

core/src/main/java/org/elasticsearch/search/aggregations/metrics/tophits/ParsedTopHits.java

@@ -0,0 +1,63 @@
+/*
+ * 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.search.aggregations.metrics.tophits;
+
+import org.elasticsearch.common.ParseField;
+import org.elasticsearch.common.xcontent.ObjectParser;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.search.SearchHits;
+import org.elasticsearch.search.aggregations.ParsedAggregation;
+
+import java.io.IOException;
+
+public class ParsedTopHits extends ParsedAggregation implements TopHits {
+
+    private SearchHits searchHits;
+
+    @Override
+    public String getType() {
+        return TopHitsAggregationBuilder.NAME;
+    }
+
+    @Override
+    public SearchHits getHits() {
+        return searchHits;
+    }
+
+    @Override
+    protected XContentBuilder doXContentBody(XContentBuilder builder, Params params) throws IOException {
+        return searchHits.toXContent(builder, params);
+    }
+
+    private static ObjectParser<ParsedTopHits, Void> PARSER =
+            new ObjectParser<>(ParsedTopHits.class.getSimpleName(), true, ParsedTopHits::new);
+    static {
+        declareAggregationFields(PARSER);
+        PARSER.declareObject((topHit, searchHits) -> topHit.searchHits = searchHits, (parser, context) -> SearchHits.fromXContent(parser),
+                new ParseField(SearchHits.Fields.HITS));
+    }
+
+    public static ParsedTopHits fromXContent(XContentParser parser, String name) throws IOException {
+        ParsedTopHits aggregation = PARSER.parse(parser, null);
+        aggregation.setName(name);
+        return aggregation;
+    }
+}

core/src/test/java/org/elasticsearch/search/aggregations/AggregationsTests.java

@@ -61,6 +61,7 @@ import org.elasticsearch.search.aggregations.metrics.percentiles.tdigest.Interna
 import org.elasticsearch.search.aggregations.metrics.percentiles.tdigest.InternalTDigestPercentilesTests;
 import org.elasticsearch.search.aggregations.metrics.scripted.InternalScriptedMetricTests;
 import org.elasticsearch.search.aggregations.metrics.sum.InternalSumTests;
+import org.elasticsearch.search.aggregations.metrics.tophits.InternalTopHitsTests;
 import org.elasticsearch.search.aggregations.metrics.valuecount.InternalValueCountTests;
 import org.elasticsearch.search.aggregations.pipeline.InternalSimpleValueTests;
 import org.elasticsearch.search.aggregations.pipeline.bucketmetrics.InternalBucketMetricValueTests;
@@ -134,6 +135,7 @@ public class AggregationsTests extends ESTestCase {
         aggsTests.add(new SignificantStringTermsTests());
         aggsTests.add(new InternalScriptedMetricTests());
         aggsTests.add(new InternalBinaryRangeTests());
+        aggsTests.add(new InternalTopHitsTests());
         return Collections.unmodifiableList(aggsTests);
     }
 

core/src/test/java/org/elasticsearch/search/aggregations/metrics/tophits/InternalTopHitsTests.java

@@ -33,9 +33,11 @@ import org.elasticsearch.common.text.Text;
 import org.elasticsearch.search.SearchHit;
 import org.elasticsearch.search.SearchHitField;
 import org.elasticsearch.search.SearchHits;
+import org.elasticsearch.search.aggregations.ParsedAggregation;
 import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.test.InternalAggregationTestCase;
 
+import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Comparator;
@@ -54,11 +56,18 @@ public class InternalTopHitsTests extends InternalAggregationTestCase<InternalTo
      * Should the test instances look like they are sorted by some fields (true) or sorted by score (false). Set here because these need
      * to be the same across the entirety of {@link #testReduceRandom()}.
      */
-    private final boolean testInstancesLookSortedByField = randomBoolean();
+    private boolean testInstancesLookSortedByField;
     /**
      * Fields shared by all instances created by {@link #createTestInstance(String, List, Map)}.
      */
-    private final SortField[] testInstancesSortFields = testInstancesLookSortedByField ? randomSortFields() : new SortField[0];
+    private SortField[] testInstancesSortFields;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+        testInstancesLookSortedByField = randomBoolean();
+        testInstancesSortFields = testInstancesLookSortedByField ? randomSortFields() : new SortField[0];
+    }
 
     @Override
     protected InternalTopHits createTestInstance(String name, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
@@ -103,6 +112,35 @@ public class InternalTopHitsTests extends InternalAggregationTestCase<InternalTo
         return new InternalTopHits(name, from, requestedSize, topDocs, searchHits, pipelineAggregators, metaData);
     }
 
+    @Override
+    protected void assertFromXContent(InternalTopHits aggregation, ParsedAggregation parsedAggregation) throws IOException {
+        final SearchHits expectedSearchHits = aggregation.getHits();
+
+        assertTrue(parsedAggregation instanceof ParsedTopHits);
+        ParsedTopHits parsed = (ParsedTopHits) parsedAggregation;
+        final SearchHits actualSearchHits = parsed.getHits();
+
+        assertEquals(expectedSearchHits.getTotalHits(), actualSearchHits.getTotalHits());
+        assertEquals(expectedSearchHits.getMaxScore(), actualSearchHits.getMaxScore(), 0.0f);
+
+        List<SearchHit> expectedHits = Arrays.asList(expectedSearchHits.getHits());
+        List<SearchHit> actualHits = Arrays.asList(actualSearchHits.getHits());
+
+        assertEquals(expectedHits.size(), actualHits.size());
+        for (int i = 0; i < expectedHits.size(); i++) {
+            SearchHit expected = expectedHits.get(i);
+            SearchHit actual = actualHits.get(i);
+
+            assertEquals(expected.getIndex(), actual.getIndex());
+            assertEquals(expected.getType(), actual.getType());
+            assertEquals(expected.getId(), actual.getId());
+            assertEquals(expected.getVersion(), actual.getVersion());
+            assertEquals(expected.getScore(), actual.getScore(), 0.0f);
+            assertEquals(expected.getFields(), actual.getFields());
+            assertEquals(expected.getSourceAsMap(), actual.getSourceAsMap());
+        }
+    }
+
     private Object randomOfType(SortField.Type type) {
         switch (type) {
         case CUSTOM:

test/framework/src/main/java/org/elasticsearch/test/InternalAggregationTestCase.java

@@ -106,6 +106,8 @@ import org.elasticsearch.search.aggregations.metrics.stats.extended.ExtendedStat
 import org.elasticsearch.search.aggregations.metrics.stats.extended.ParsedExtendedStats;
 import org.elasticsearch.search.aggregations.metrics.sum.ParsedSum;
 import org.elasticsearch.search.aggregations.metrics.sum.SumAggregationBuilder;
+import org.elasticsearch.search.aggregations.metrics.tophits.ParsedTopHits;
+import org.elasticsearch.search.aggregations.metrics.tophits.TopHitsAggregationBuilder;
 import org.elasticsearch.search.aggregations.metrics.valuecount.ParsedValueCount;
 import org.elasticsearch.search.aggregations.metrics.valuecount.ValueCountAggregationBuilder;
 import org.elasticsearch.search.aggregations.pipeline.InternalSimpleValue;
@@ -187,6 +189,7 @@ public abstract class InternalAggregationTestCase<T extends InternalAggregation>
         map.put(SignificantStringTerms.NAME, (p, c) -> ParsedSignificantStringTerms.fromXContent(p, (String) c));
         map.put(ScriptedMetricAggregationBuilder.NAME, (p, c) -> ParsedScriptedMetric.fromXContent(p, (String) c));
         map.put(IpRangeAggregationBuilder.NAME, (p, c) -> ParsedBinaryRange.fromXContent(p, (String) c));
+        map.put(TopHitsAggregationBuilder.NAME, (p, c) -> ParsedTopHits.fromXContent(p, (String) c));
 
         namedXContents = map.entrySet().stream()
                 .map(entry -> new NamedXContentRegistry.Entry(Aggregation.class, new ParseField(entry.getKey()), entry.getValue()))