fix(parent/agg): deserialize parent aggregation

CHANGELOG.md

@@ -25,6 +25,7 @@ This section is for maintaining a changelog for all breaking changes for the cli
 
 ### Fixed
 - Fix version and build ([#254](https://github.com/opensearch-project/opensearch-java/pull/254))
+- Deserialize aggregation containing a parent aggregation ([#706](https://github.com/opensearch-project/opensearch-java/pull/706))
 
 ### Security
 

java-client/src/main/java/org/opensearch/client/opensearch/_types/aggregations/Aggregate.java

@@ -136,6 +136,8 @@ public enum Kind implements JsonEnum {
 
         Nested("nested"),
 
+        Parent("parent"),
+
         PercentilesBucket("percentiles_bucket"),
 
         Range("range"),
@@ -894,6 +896,23 @@ public NestedAggregate nested() {
         return TaggedUnionUtils.get(this, Kind.Nested);
     }
 
+    /**
+     * Is this variant instance of kind {@code parent}?
+     */
+    public boolean isParent() {
+        return _kind == Kind.Parent;
+    }
+
+    /**
+     * Get the {@code parent} variant value.
+     *
+     * @throws IllegalStateException
+     *             if the current variant is not of the {@code parent} kind.
+     */
+    public ParentAggregate parent() {
+        return TaggedUnionUtils.get(this, Kind.Parent);
+    }
+
     /**
      * Is this variant instance of kind {@code percentiles_bucket}?
      */
@@ -1754,6 +1773,16 @@ public ObjectBuilder<Aggregate> percentilesBucket(PercentilesBucketAggregate v)
             return this;
         }
 
+        public ObjectBuilder<Aggregate> parent(ParentAggregate v) {
+            this._kind = Kind.Parent;
+            this._value = v;
+            return this;
+        }
+
+        public ObjectBuilder<Aggregate> parent(Function<ParentAggregate.Builder, ObjectBuilder<ParentAggregate>> fn) {
+            return this.parent(fn.apply(new ParentAggregate.Builder()).build());
+        }
+
         public ObjectBuilder<Aggregate> percentilesBucket(
             Function<PercentilesBucketAggregate.Builder, ObjectBuilder<PercentilesBucketAggregate>> fn
         ) {
@@ -2075,6 +2104,7 @@ public Aggregate build() {
         deserializers.put("missing", MissingAggregate._DESERIALIZER);
         deserializers.put("multi_terms", MultiTermsAggregate._DESERIALIZER);
         deserializers.put("nested", NestedAggregate._DESERIALIZER);
+        deserializers.put("parent", ParentAggregate._DESERIALIZER);
         deserializers.put("percentiles_bucket", PercentilesBucketAggregate._DESERIALIZER);
         deserializers.put("range", RangeAggregate._DESERIALIZER);
         deserializers.put("rate", RateAggregate._DESERIALIZER);

java-client/src/main/java/org/opensearch/client/opensearch/_types/aggregations/ParentAggregate.java

@@ -0,0 +1,101 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. 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.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.client.opensearch._types.aggregations;
+
+import java.util.function.Function;
+import org.opensearch.client.json.JsonpDeserializable;
+import org.opensearch.client.json.JsonpDeserializer;
+import org.opensearch.client.json.ObjectBuilderDeserializer;
+import org.opensearch.client.json.ObjectDeserializer;
+import org.opensearch.client.util.ObjectBuilder;
+
+// typedef: _types.aggregations.ParentAggregate
+
+@JsonpDeserializable
+public class ParentAggregate extends SingleBucketAggregateBase implements AggregateVariant {
+    // ---------------------------------------------------------------------------------------------
+
+    private ParentAggregate(Builder builder) {
+        super(builder);
+
+    }
+
+    public static ParentAggregate of(Function<Builder, ObjectBuilder<ParentAggregate>> fn) {
+        return fn.apply(new Builder()).build();
+    }
+
+    @Override
+    public Aggregate.Kind _aggregateKind() {
+        return Aggregate.Kind.Parent;
+    }
+
+    // ---------------------------------------------------------------------------------------------
+
+    /**
+     * Builder for {@link ParentAggregate}.
+     */
+
+    public static class Builder extends SingleBucketAggregateBase.AbstractBuilder<Builder> implements ObjectBuilder<ParentAggregate> {
+        @Override
+        protected Builder self() {
+            return this;
+        }
+
+        /**
+         * Builds a {@link ParentAggregate}.
+         *
+         * @throws NullPointerException
+         *             if some of the required fields are null.
+         */
+        public ParentAggregate build() {
+            _checkSingleUse();
+
+            return new ParentAggregate(this);
+        }
+    }
+
+    // ---------------------------------------------------------------------------------------------
+
+    /**
+     * Json deserializer for {@link ParentAggregate}
+     */
+    public static final JsonpDeserializer<ParentAggregate> _DESERIALIZER = ObjectBuilderDeserializer.lazy(
+        Builder::new,
+        ParentAggregate::setupParentAggregateDeserializer
+    );
+
+    protected static void setupParentAggregateDeserializer(ObjectDeserializer<ParentAggregate.Builder> op) {
+        SingleBucketAggregateBase.setupSingleBucketAggregateBaseDeserializer(op);
+    }
+
+}

java-client/src/test/java/org/opensearch/client/opensearch/core/AggregateResponseTest.java

@@ -0,0 +1,54 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.client.opensearch.core;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import jakarta.json.stream.JsonParser;
+import java.io.StringReader;
+import java.util.Map;
+import org.junit.Test;
+import org.opensearch.client.opensearch._types.aggregations.Aggregate;
+import org.opensearch.client.opensearch._types.aggregations.ParentAggregate;
+import org.opensearch.client.opensearch.model.ModelTestCase;
+
+public class AggregateResponseTest extends ModelTestCase {
+
+    @Test
+    public void shouldCreateParentAggregate() {
+        // given
+        final Aggregate aggregate = Aggregate.of((b) -> b.parent((p) -> p.docCount(789L)));
+
+        // when
+        final ParentAggregate parentAggregate = aggregate.parent();
+
+        // then
+        assertEquals(parentAggregate._aggregateKind(), Aggregate.Kind.Parent);
+        assertEquals(parentAggregate.docCount(), 789L);
+    }
+
+    @Test
+    public void shouldDeserializeParentAggregate() throws JsonProcessingException {
+        // given
+        final String parentAggreationJson = "{\"took\": 3,\"timed_out\": false,"
+            + "\"_shards\": {\"total\": 1,\"successful\": 1,\"skipped\": 0,\"failed\": 0},"
+            + "\"hits\": {\"total\": {\"value\": 0,\"relation\": \"eq\"},\"hits\": []},"
+            + "\"aggregations\": {\"parent#foo\": {\"doc_count\": 123456}}}";
+        final JsonParser parser = mapper.jsonProvider().createParser(new StringReader(parentAggreationJson));
+
+        // when
+        final SearchResponse<Object> response = SearchResponse._DESERIALIZER.deserialize(parser, mapper);
+
+        // then
+        final Map<String, Aggregate> aggregations = response.aggregations();
+        assertFalse(aggregations.isEmpty());
+        assertTrue(aggregations.containsKey("foo"));
+        assertEquals(aggregations.get("foo").parent()._aggregateKind(), Aggregate.Kind.Parent);
+        assertEquals(aggregations.get("foo").parent().docCount(), 123456L);
+    }
+}