Encapsulate client specific aggregation return types.

Original Pull Request #1921
Closes #1920

Author: sothawo

src/main/asciidoc/reference/elasticsearch-migration-guide-4.2-4.3.adoc

@@ -30,6 +30,12 @@ Check the sections on <<elasticsearch-migration-guide-4.2-4.3.deprecations>> and
 * In the `org.springframework.data.elasticsearch.annotations.Document` annotation the `versionType()` property has changed to `org.springframework.data.elasticsearch.annotations.Document.VersionType`, the available enum values are the same.
 * In the `org.springframework.data.elasticsearch.core.query.Query` interface the `searchType()` property has changed to `org.springframework.data.elasticsearch.core.query.Query.SearchType`, the available enum values are the same.
 * In the `org.springframework.data.elasticsearch.core.query.Query` interface the return value of  `timeout()` was changed to `java.time.Duration`.
+* The `SearchHits<T>`class does not contain the `org.elasticsearch.search.aggregations.Aggregations` anymore.
+Instead it now contains an instance of the `org.springframework.data.elasticsearch.core.AggregationsContainer<T>` class where `T` is the concrete aggregations type from the underlying client that is used.
+Currently this will be a `org
+.springframework.data.elasticsearch.core.clients.elasticsearch7.ElasticsearchAggregations` object; later different implementations will be available.
+The same change has been done to the `ReactiveSearchOperations.aggregate()` functions, the now return a `Flux<AggregationContainer<?>>`.
+Programs using the aggregations need to be changed to cast the returned value to the appropriate class to further proces it.
 
 === Handling of field and sourceFilter properties of Query
 

src/main/java/org/springframework/data/elasticsearch/core/AggregationContainer.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2021 the original author or authors.
+ *
+ * Licensed 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
+ *
+ *      https://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.springframework.data.elasticsearch.core;
+
+/**
+ * Aggregation container used in the Spring Data Elasticsearch API for a single aggregation. The concrete
+ * implementations must be provided by the code handling the direct communication with Elasticsearch.
+ *
+ * @author Peter-Josef Meisch
+ * @param <T> the aggregation class from the used client implementation.
+ * @since 4.3
+ */
+public interface AggregationContainer<T> {
+	/**
+	 * @return the concrete aggregations implementation
+	 */
+	T aggregation();
+}

src/main/java/org/springframework/data/elasticsearch/core/AggregationsContainer.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2021 the original author or authors.
+ *
+ * Licensed 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
+ *
+ *      https://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.springframework.data.elasticsearch.core;
+
+/**
+ * Aggregations container used in the Spring Data Elasticsearch API. The concrete implementations must be provided by
+ * the code handling the direct communication with Elasticsearch.
+ *
+ * @author Peter-Josef Meisch
+ * @param <T> the aggregations class from the used client implementation.
+ * @since 4.3
+ */
+public interface AggregationsContainer<T> {
+	/**
+	 * @return the concrete aggregations implementation
+	 */
+	T aggregations();
+}

src/main/java/org/springframework/data/elasticsearch/core/ReactiveElasticsearchTemplate.java

@@ -44,7 +44,6 @@
 import org.elasticsearch.index.reindex.BulkByScrollResponse;
 import org.elasticsearch.index.reindex.DeleteByQueryRequest;
 import org.elasticsearch.index.reindex.UpdateByQueryRequest;
-import org.elasticsearch.search.aggregations.Aggregation;
 import org.elasticsearch.search.suggest.Suggest;
 import org.elasticsearch.search.suggest.SuggestBuilder;
 import org.reactivestreams.Publisher;
@@ -59,6 +58,7 @@
 import org.springframework.data.elasticsearch.UncategorizedElasticsearchException;
 import org.springframework.data.elasticsearch.client.reactive.ReactiveElasticsearchClient;
 import org.springframework.data.elasticsearch.core.EntityOperations.AdaptibleEntity;
+import org.springframework.data.elasticsearch.core.clients.elasticsearch7.ElasticsearchAggregation;
 import org.springframework.data.elasticsearch.core.cluster.DefaultReactiveClusterOperations;
 import org.springframework.data.elasticsearch.core.cluster.ReactiveClusterOperations;
 import org.springframework.data.elasticsearch.core.convert.ElasticsearchConverter;
@@ -782,12 +782,12 @@ private Mono<SearchDocumentResponse> doFindForResponse(Query query, Class<?> cla
 	}
 
 	@Override
-	public Flux<Aggregation> aggregate(Query query, Class<?> entityType) {
+	public Flux<AggregationContainer<?>> aggregate(Query query, Class<?> entityType) {
 		return aggregate(query, entityType, getIndexCoordinatesFor(entityType));
 	}
 
 	@Override
-	public Flux<Aggregation> aggregate(Query query, Class<?> entityType, IndexCoordinates index) {
+	public Flux<AggregationContainer<?>> aggregate(Query query, Class<?> entityType, IndexCoordinates index) {
 		return doAggregate(query, entityType, index);
 	}
 
@@ -808,7 +808,7 @@ private Flux<Suggest> doSuggest(SuggestBuilder suggestion, IndexCoordinates inde
 		});
 	}
 
-	private Flux<Aggregation> doAggregate(Query query, Class<?> entityType, IndexCoordinates index) {
+	private Flux<AggregationContainer<?>> doAggregate(Query query, Class<?> entityType, IndexCoordinates index) {
 		return Flux.defer(() -> {
 			SearchRequest request = requestFactory.searchRequest(query, entityType, index);
 			request = prepareSearchRequest(request, false);
@@ -872,14 +872,14 @@ protected Mono<SearchDocumentResponse> doFindForResponse(SearchRequest request)
 	 * @param request the already prepared {@link SearchRequest} ready to be executed.
 	 * @return a {@link Flux} emitting the result of the operation.
 	 */
-	protected Flux<Aggregation> doAggregate(SearchRequest request) {
+	protected Flux<AggregationContainer<?>> doAggregate(SearchRequest request) {
 
 		if (QUERY_LOGGER.isDebugEnabled()) {
 			QUERY_LOGGER.debug("Executing doCount: {}", request);
 		}
 
 		return Flux.from(execute(client -> client.aggregate(request))) //
-				.onErrorResume(NoSuchIndexException.class, it -> Flux.empty());
+				.onErrorResume(NoSuchIndexException.class, it -> Flux.empty()).map(ElasticsearchAggregation::new);
 	}
 
 	/**

src/main/java/org/springframework/data/elasticsearch/core/ReactiveSearchOperations.java

@@ -20,7 +20,6 @@
 
 import java.util.List;
 
-import org.elasticsearch.search.aggregations.Aggregation;
 import org.elasticsearch.search.suggest.Suggest;
 import org.elasticsearch.search.suggest.SuggestBuilder;
 import org.springframework.data.domain.Pageable;
@@ -185,7 +184,7 @@ default <T> Mono<SearchPage<T>> searchForPage(Query query, Class<T> entityType,
 	 * @return a {@link Flux} emitting matching aggregations one by one.
 	 * @since 4.0
 	 */
-	Flux<Aggregation> aggregate(Query query, Class<?> entityType);
+	Flux<AggregationContainer<?>> aggregate(Query query, Class<?> entityType);
 
 	/**
 	 * Perform an aggregation specified by the given {@link Query query}. <br />
@@ -196,7 +195,7 @@ default <T> Mono<SearchPage<T>> searchForPage(Query query, Class<T> entityType,
 	 * @return a {@link Flux} emitting matching aggregations one by one.
 	 * @since 4.0
 	 */
-	Flux<Aggregation> aggregate(Query query, Class<?> entityType, IndexCoordinates index);
+	Flux<AggregationContainer<?>> aggregate(Query query, Class<?> entityType, IndexCoordinates index);
 
 	/**
 	 * Does a suggest query

src/main/java/org/springframework/data/elasticsearch/core/SearchHitMapping.java

@@ -22,7 +22,6 @@
 import java.util.Map;
 import java.util.stream.Collectors;
 
-import org.elasticsearch.search.aggregations.Aggregations;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.data.elasticsearch.core.convert.ElasticsearchConverter;
@@ -95,7 +94,7 @@ private SearchHitsImpl<T> mapHitsFromResponse(SearchDocumentResponse searchDocum
 			SearchHit<T> hit = mapHit(document, content);
 			searchHits.add(hit);
 		}
-		Aggregations aggregations = searchDocumentResponse.getAggregations();
+		AggregationsContainer<?> aggregations = searchDocumentResponse.getAggregations();
 		TotalHitsRelation totalHitsRelation = TotalHitsRelation.valueOf(searchDocumentResponse.getTotalHitsRelation());
 
 		return new SearchHitsImpl<>(totalHits, totalHitsRelation, maxScore, scrollId, searchHits, aggregations);
@@ -225,7 +224,7 @@ private SearchHits<?> mapInnerDocuments(SearchHits<SearchDocument> searchHits, C
 
 	/**
 	 * find a {@link ElasticsearchPersistentEntity} following the property chain defined by the nested metadata
-	 * 
+	 *
 	 * @param persistentEntity base entity
 	 * @param nestedMetaData nested metadata
 	 * @return A {@link ElasticsearchPersistentEntityWithNestedMetaData} containing the found entity or null together with

src/main/java/org/springframework/data/elasticsearch/core/SearchHits.java

@@ -18,13 +18,12 @@
 import java.util.Iterator;
 import java.util.List;
 
-import org.elasticsearch.search.aggregations.Aggregations;
 import org.springframework.data.util.Streamable;
 import org.springframework.lang.Nullable;
 
 /**
  * Encapsulates a list of {@link SearchHit}s with additional information from the search.
- * 
+ *
  * @param <T> the result data class.
  * @author Sascha Woo
  * @since 4.0
@@ -35,7 +34,7 @@ public interface SearchHits<T> extends Streamable<SearchHit<T>> {
 	 * @return the aggregations.
 	 */
 	@Nullable
-	Aggregations getAggregations();
+	AggregationsContainer<?> getAggregations();
 
 	/**
 	 * @return the maximum score

src/main/java/org/springframework/data/elasticsearch/core/SearchHitsImpl.java

@@ -18,7 +18,6 @@
 import java.util.Collections;
 import java.util.List;
 
-import org.elasticsearch.search.aggregations.Aggregations;
 import org.springframework.data.util.Lazy;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
@@ -39,7 +38,7 @@ public class SearchHitsImpl<T> implements SearchScrollHits<T> {
 	@Nullable private final String scrollId;
 	private final List<? extends SearchHit<T>> searchHits;
 	private final Lazy<List<SearchHit<T>>> unmodifiableSearchHits;
-	@Nullable private final Aggregations aggregations;
+	@Nullable private final AggregationsContainer<?> aggregations;
 
 	/**
 	 * @param totalHits the number of total hits for the search
@@ -50,7 +49,7 @@ public class SearchHitsImpl<T> implements SearchScrollHits<T> {
 	 * @param aggregations the aggregations if available
 	 */
 	public SearchHitsImpl(long totalHits, TotalHitsRelation totalHitsRelation, float maxScore, @Nullable String scrollId,
-			List<? extends SearchHit<T>> searchHits, @Nullable Aggregations aggregations) {
+			List<? extends SearchHit<T>> searchHits, @Nullable AggregationsContainer<?> aggregations) {
 
 		Assert.notNull(searchHits, "searchHits must not be null");
 
@@ -113,7 +112,7 @@ public String toString() {
 	// region aggregations
 	@Override
 	@Nullable
-	public Aggregations getAggregations() {
+	public AggregationsContainer<?> getAggregations() {
 		return aggregations;
 	}
 	// endregion

src/main/java/org/springframework/data/elasticsearch/core/SearchHitsIterator.java

@@ -15,7 +15,6 @@
  */
 package org.springframework.data.elasticsearch.core;
 
-import org.elasticsearch.search.aggregations.Aggregations;
 import org.springframework.data.util.CloseableIterator;
 import org.springframework.lang.Nullable;
 
@@ -33,7 +32,7 @@ public interface SearchHitsIterator<T> extends CloseableIterator<SearchHit<T>> {
 	 * @return the aggregations.
 	 */
 	@Nullable
-	Aggregations getAggregations();
+	AggregationsContainer<?> getAggregations();
 
 	/**
 	 * @return the maximum score

src/main/java/org/springframework/data/elasticsearch/core/StreamQueries.java

@@ -22,7 +22,6 @@
 import java.util.function.Consumer;
 import java.util.function.Function;
 
-import org.elasticsearch.search.aggregations.Aggregations;
 import org.springframework.data.elasticsearch.client.util.ScrollState;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
@@ -55,7 +54,7 @@ static <T> SearchHitsIterator<T> streamResults(int maxCount, SearchScrollHits<T>
 		Assert.notNull(continueScrollFunction, "continueScrollFunction must not be null.");
 		Assert.notNull(clearScrollConsumer, "clearScrollConsumer must not be null.");
 
-		Aggregations aggregations = searchHits.getAggregations();
+		AggregationsContainer<?> aggregations = searchHits.getAggregations();
 		float maxScore = searchHits.getMaxScore();
 		long totalHits = searchHits.getTotalHits();
 		TotalHitsRelation totalHitsRelation = searchHits.getTotalHitsRelation();
@@ -78,7 +77,7 @@ public void close() {
 
 			@Override
 			@Nullable
-			public Aggregations getAggregations() {
+			public AggregationsContainer<?> getAggregations() {
 				return aggregations;
 			}
 

src/main/java/org/springframework/data/elasticsearch/core/clients/elasticsearch7/ElasticsearchAggregation.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2021 the original author or authors.
+ *
+ * Licensed 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
+ *
+ *      https://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.springframework.data.elasticsearch.core.clients.elasticsearch7;
+
+import org.elasticsearch.search.aggregations.Aggregation;
+import org.springframework.data.elasticsearch.core.AggregationContainer;
+import org.springframework.lang.NonNull;
+
+/**
+ * AggregationContainer implementation for an Elasticsearch7 aggregation.
+ *
+ * @author Peter-Josef Meisch
+ * @since 4.3
+ */
+public class ElasticsearchAggregation implements AggregationContainer<Aggregation> {
+
+	private final Aggregation aggregation;
+
+	public ElasticsearchAggregation(Aggregation aggregation) {
+		this.aggregation = aggregation;
+	}
+
+	@NonNull
+	@Override
+	public Aggregation aggregation() {
+		return aggregation;
+	}
+}

src/main/java/org/springframework/data/elasticsearch/core/clients/elasticsearch7/ElasticsearchAggregations.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2021 the original author or authors.
+ *
+ * Licensed 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
+ *
+ *      https://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.springframework.data.elasticsearch.core.clients.elasticsearch7;
+
+import org.elasticsearch.search.aggregations.Aggregations;
+import org.springframework.data.elasticsearch.core.AggregationsContainer;
+import org.springframework.lang.NonNull;
+
+/**
+ * AggregationsContainer implementation for the Elasticsearch7 aggregations.
+ *
+ * @author Peter-Josef Meisch
+ * @since 4.3
+ */
+public class ElasticsearchAggregations implements AggregationsContainer<Aggregations> {
+
+	private final Aggregations aggregations;
+
+	public ElasticsearchAggregations(Aggregations aggregations) {
+		this.aggregations = aggregations;
+	}
+
+	@NonNull
+	@Override
+	public Aggregations aggregations() {
+		return aggregations;
+	}
+}

src/main/java/org/springframework/data/elasticsearch/core/clients/elasticsearch7/package-info.java

@@ -0,0 +1,6 @@
+/**
+ * Classes and interfaces used by the code that uses Elasticsearch 7 client libraries
+ */
+@org.springframework.lang.NonNullApi
+@org.springframework.lang.NonNullFields
+package org.springframework.data.elasticsearch.core.clients.elasticsearch7;