Use ExistsRequest instead of GetRequest to check if documents exists.

Original Pull Re1uest #2728
Closes #2726

Author: mawen12

src/main/java/org/springframework/data/elasticsearch/client/elc/ElasticsearchTemplate.java

@@ -125,7 +125,7 @@ private ClusterTemplate getClusterTemplate() {
 	public <T> T get(String id, Class<T> clazz, IndexCoordinates index) {
 
 		GetRequest getRequest = requestConverter.documentGetRequest(elasticsearchConverter.convertId(id),
-				routingResolver.getRouting(), index, false);
+				routingResolver.getRouting(), index);
 		GetResponse<EntityAsMap> getResponse = execute(client -> client.get(getRequest, EntityAsMap.class));
 
 		ReadDocumentCallback<T> callback = new ReadDocumentCallback<>(elasticsearchConverter, clazz, index);
@@ -221,9 +221,9 @@ protected boolean doExists(String id, IndexCoordinates index) {
 		Assert.notNull(id, "id must not be null");
 		Assert.notNull(index, "index must not be null");
 
-		GetRequest request = requestConverter.documentGetRequest(id, routingResolver.getRouting(), index, true);
+		ExistsRequest request = requestConverter.documentExistsRequest(id, routingResolver.getRouting(), index);
 
-		return execute(client -> client.get(request, EntityAsMap.class)).found();
+		return execute(client -> client.exists(request)).value();
 	}
 
 	@Override

src/main/java/org/springframework/data/elasticsearch/client/elc/ReactiveElasticsearchClient.java

@@ -128,6 +128,13 @@ public <T> Mono<GetResponse<T>> get(GetRequest request, Class<T> tClass) {
 		return Mono.fromFuture(transport.performRequestAsync(request, endpoint, transportOptions));
 	}
 
+	public Mono<BooleanResponse> exists(ExistsRequest request) {
+
+		Assert.notNull(request, "request must not be null");
+
+		return Mono.fromFuture(transport.performRequestAsync(request, ExistsRequest._ENDPOINT, transportOptions));
+	}
+
 	public <T, P> Mono<UpdateResponse<T>> update(UpdateRequest<T, P> request, Class<T> clazz) {
 
 		Assert.notNull(request, "request must not be null");

src/main/java/org/springframework/data/elasticsearch/client/elc/ReactiveElasticsearchTemplate.java

@@ -25,6 +25,7 @@
 import co.elastic.clients.elasticsearch.core.search.ResponseBody;
 import co.elastic.clients.json.JsonpMapper;
 import co.elastic.clients.transport.Version;
+import co.elastic.clients.transport.endpoints.BooleanResponse;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import reactor.core.publisher.Flux;
@@ -148,9 +149,11 @@ protected Mono<Boolean> doExists(String id, IndexCoordinates index) {
 		Assert.notNull(id, "id must not be null");
 		Assert.notNull(index, "index must not be null");
 
-		GetRequest getRequest = requestConverter.documentGetRequest(id, routingResolver.getRouting(), index, true);
+		ExistsRequest existsRequest = requestConverter.documentExistsRequest(id, routingResolver.getRouting(), index);
 
-		return Mono.from(execute(client -> client.get(getRequest, EntityAsMap.class))).map(GetResult::found) //
+		return Mono.from(execute(
+				((ClientCallback<Publisher<BooleanResponse>>) client -> client.exists(existsRequest))))
+				.map(BooleanResponse::value) //
 				.onErrorReturn(NoSuchIndexException.class, false);
 	}
 
@@ -171,7 +174,7 @@ public <T> Mono<T> get(String id, Class<T> entityType, IndexCoordinates index) {
 		Assert.notNull(entityType, "entityType must not be null");
 		Assert.notNull(index, "index must not be null");
 
-		GetRequest getRequest = requestConverter.documentGetRequest(id, routingResolver.getRouting(), index, false);
+		GetRequest getRequest = requestConverter.documentGetRequest(id, routingResolver.getRouting(), index);
 
 		Mono<GetResponse<EntityAsMap>> getResponse = Mono
 				.from(execute(client -> client.get(getRequest, EntityAsMap.class)));

src/main/java/org/springframework/data/elasticsearch/client/elc/RequestConverter.java

@@ -780,25 +780,26 @@ public BulkRequest documentBulkRequest(List<?> queries, BulkOptions bulkOptions,
 		return builder.build();
 	}
 
-	public GetRequest documentGetRequest(String id, @Nullable String routing, IndexCoordinates indexCoordinates,
-			boolean forExistsRequest) {
+	public GetRequest documentGetRequest(String id, @Nullable String routing, IndexCoordinates indexCoordinates) {
 
 		Assert.notNull(id, "id must not be null");
 		Assert.notNull(indexCoordinates, "indexCoordinates must not be null");
 
-		return GetRequest.of(grb -> {
-			grb //
+		return GetRequest.of(grb -> grb //
 					.index(indexCoordinates.getIndexName()) //
 					.id(id) //
-					.routing(routing);
+					.routing(routing));
+	}
 
-			if (forExistsRequest) {
-				grb.source(scp -> scp.fetch(false));
-			}
+	public co.elastic.clients.elasticsearch.core.ExistsRequest documentExistsRequest(String id, @Nullable String routing, IndexCoordinates indexCoordinates) {
 
-			return grb;
-		});
+		Assert.notNull(id, "id must not be null");
+		Assert.notNull(indexCoordinates, "indexCoordinates must not be null");
 
+		return co.elastic.clients.elasticsearch.core.ExistsRequest.of(erb -> erb
+				.index(indexCoordinates.getIndexName())
+				.id(id)
+				.routing(routing));
 	}
 
 	public <T> MgetRequest documentMgetRequest(Query query, Class<T> clazz, IndexCoordinates index) {