DATAES-519 - Add reactive repository support.

Reactive Elasticsearch repository support builds on the core repository support utilizing
operations provided via ReactiveElasticsearchOperations executed by a ReactiveElasticsearchClient.

Spring Data Elasticsearchs reactive repository support uses Project Reactor as its reactive
composition library of choice.

There are 3 main interfaces to be used:

* ReactiveRepository
* ReactiveCrudRepository
* ReactiveSortingRepository

For Java configuration, use the @EnableReactiveElasticsearchRepositories annotation.
The following listing shows how to use Java configuration for a repository:

@Configuration
@EnableReactiveElasticsearchRepositories
public class Config extends AbstractReactiveElasticsearchConfiguration {

  @Override
  public ReactiveElasticsearchClient reactiveElasticsearchClient() {
    return ReactiveRestClients.create(ClientConfiguration.localhost());
  }
}

Using a repository that extends ReactiveSortingRepository makes all CRUD operations available
as well as methods for sorted access to the entities. Working with the repository instance is a matter of dependency
injecting it into a client.

The repository itself allows defining additional methods backed by the inferred proxy.

public interface ReactivePersonRepository extends ReactiveSortingRepository<Person, String> {

  Flux<Person> findByFirstname(String firstname);

  Flux<Person> findByFirstname(Publisher<String> firstname);

  Flux<Person> findByFirstnameOrderByLastname(String firstname);

  Flux<Person> findByFirstname(String firstname, Sort sort);

  Flux<Person> findByFirstname(String firstname, Pageable page);

  Mono<Person> findByFirstnameAndLastname(String firstname, String lastname);

  Mono<Person> findFirstByLastname(String lastname);

  @Query("{ \"bool\" : { \"must\" : { \"term\" : { \"lastname\" : \"?0\" } } } }")
  Flux<Person> findByLastname(String lastname);

  Mono<Long> countByFirstname(String firstname)

  Mono<Boolean> existsByFirstname(String firstname)

  Mono<Long> deleteByFirstname(String firstname)
}

Original Pull Request: #235

pom.xml

@@ -270,6 +270,9 @@
 					<includes>
 						<include>**/*Tests.java</include>
 					</includes>
+					<systemPropertyVariables>
+						<es.set.netty.runtime.available.processors>false</es.set.netty.runtime.available.processors>
+					</systemPropertyVariables>
 				</configuration>
 			</plugin>
 		</plugins>

src/main/asciidoc/index.adoc

@@ -31,6 +31,7 @@ include::{spring-data-commons-docs}/repositories.adoc[]
 include::reference/elasticsearch-clients.adoc[]
 include::reference/data-elasticsearch.adoc[]
 include::reference/reactive-elasticsearch-operations.adoc[]
+include::reference/reactive-elasticsearch-repositories.adoc[]
 include::reference/elasticsearch-misc.adoc[]
 :leveloffset: -1
 

src/main/asciidoc/reference/reactive-elasticsearch-repositories.adoc

@@ -0,0 +1,130 @@
+[[elasticsearch.reactive.repositories]]
+= Reactive Elasticsearch Repositories
+
+Reactive Elasticsearch repository support builds on the core repository support explained in <<repositories>> utilizing
+operations provided via <<elasticsearch.reactive.operations>> executed by a <<elasticsearch.clients.reactive>>.
+
+Spring Data Elasticsearchs reactive repository support uses https://projectreactor.io/[Project Reactor] as its reactive
+composition library of choice.
+
+There are 3 main interfaces to be used:
+
+* `ReactiveRepository`
+* `ReactiveCrudRepository`
+* `ReactiveSortingRepository`
+
+[[elasticsearch.reactive.repositories.usage]]
+== Usage
+
+To access domain objects stored in a Elasticsearch using a `Repository`, just create an interface for it.
+Before you can actually go on and do that you will need an entity.
+
+.Sample `Person` entity
+====
+[source,java]
+----
+public class Person {
+
+  @Id
+  private String id;
+  private String firstname;
+  private String lastname;
+  private Address address;
+
+  // … getters and setters omitted
+}
+----
+====
+
+NOTE: Please note that the `id` property needs to be of type `String`.
+
+.Basic repository interface to persist Person entities
+====
+[source]
+----
+public interface ReactivePersonRepository extends ReactiveSortingRepository<Person, String> {
+
+  Flux<Person> findByFirstname(String firstname);                                   <1>
+
+  Flux<Person> findByFirstname(Publisher<String> firstname);                        <2>
+
+  Flux<Person> findByFirstnameOrderByLastname(String firstname);                    <3>
+
+  Flux<Person> findByFirstname(String firstname, Sort sort);                        <4>
+
+  Flux<Person> findByFirstname(String firstname, Pageable page);                    <5>
+
+  Mono<Person> findByFirstnameAndLastname(String firstname, String lastname);       <6>
+
+  Mono<Person> findFirstByLastname(String lastname);                                <7>
+
+  @Query("{ \"bool\" : { \"must\" : { \"term\" : { \"lastname\" : \"?0\" } } } }")
+  Flux<Person> findByLastname(String lastname);                                     <8>
+
+  Mono<Long> countByFirstname(String firstname)                                     <9>
+
+  Mono<Boolean> existsByFirstname(String firstname)                                 <10>
+
+  Mono<Long> deleteByFirstname(String firstname)                                    <11>
+}
+----
+<1> The method shows a query for all people with the given `lastname`.
+<2> Finder method awaiting input from `Publisher` to bind parameter value for `firstname`.
+<3> Finder method ordering matching documents by `lastname`.
+<4> Finder method ordering matching documents by the expression defined via the `Sort` parameter.
+<5> Use `Pageable` to pass offset and sorting parameters to the database.
+<6> Finder method concating criteria using `And` / `Or` keywords.
+<7> Find the first matching entity.
+<8> The method shows a query for all people with the given `lastname` looked up by running the annotated `@Query` with given
+parameters.
+<9> Count all entities with matching `firstname`.
+<10> Check if at least one entity with matching `firstname` exists.
+<11> Delete all entites with matching `firstname`.
+====
+
+[[elasticsearch.reactive.repositories.configuration]]
+== Configuration
+
+For Java configuration, use the `@EnableReactiveElasticsearchRepositories` annotation. If no base package is configured,
+the infrastructure scans the package of the annotated configuration class.
+
+The following listing shows how to use Java configuration for a repository:
+
+.Java configuration for repositories
+====
+[source,java]
+----
+@Configuration
+@EnableReactiveElasticsearchRepositories
+public class Config extends AbstractReactiveElasticsearchConfiguration {
+
+  @Override
+  public ReactiveElasticsearchClient reactiveElasticsearchClient() {
+    return ReactiveRestClients.create(ClientConfiguration.localhost());
+  }
+}
+----
+====
+
+Because the repository from the previous example extends `ReactiveSortingRepository`, all CRUD operations are available
+as well as methods for sorted access to the entities. Working with the repository instance is a matter of dependency
+injecting it into a client, as the following example shows:
+
+.Sorted access to Person entities
+====
+[source,java]
+----
+public class PersonRepositoryTests {
+
+  @Autowired ReactivePersonRepository repository;
+
+  @Test
+  public void sortsElementsCorrectly() {
+
+    Flux<Person> persons = repository.findAll(Sort.by(new Order(ASC, "lastname")));
+
+    // ...
+  }
+}
+----
+====

src/main/java/org/springframework/data/elasticsearch/NoSuchIndexException.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch;
+
+import org.springframework.dao.NonTransientDataAccessResourceException;
+
+/**
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+public class NoSuchIndexException extends NonTransientDataAccessResourceException {
+
+	private final String index;
+
+	public NoSuchIndexException(String index, Throwable cause) {
+		super(String.format("Index %s not found.", index), cause);
+		this.index = index;
+	}
+
+	public String getIndex() {
+		return index;
+	}
+}

src/main/java/org/springframework/data/elasticsearch/client/ClientConfiguration.java

@@ -42,6 +42,22 @@ public interface ClientConfiguration {
 		return new ClientConfigurationBuilder();
 	}
 
+	/**
+	 * Creates a new {@link ClientConfiguration} instance configured to localhost.
+	 * <p/>
+	 *
+	 * <pre class="code">
+	 * // "localhost:9200"
+	 * ClientConfiguration configuration = ClientConfiguration.localhost();
+	 * </pre>
+	 *
+	 * @return a new {@link ClientConfiguration} instance
+	 * @see ClientConfigurationBuilder#connectedToLocalhost()
+	 */
+	static ClientConfiguration localhost() {
+		return new ClientConfigurationBuilder().connectedToLocalhost().build();
+	}
+
 	/**
 	 * Creates a new {@link ClientConfiguration} instance configured to a single host given {@code hostAndPort}.
 	 * <p/>

src/main/java/org/springframework/data/elasticsearch/client/reactive/DefaultReactiveElasticsearchClient.java

@@ -545,7 +545,7 @@ public class DefaultReactiveElasticsearchClient implements ReactiveElasticsearch
 			return Mono.justOrEmpty(responseType
 					.cast(ReflectionUtils.invokeMethod(fromXContent, responseType, createParser(mediaType, content))));
 
-		} catch (Exception errorParseFailure) {
+		} catch (Throwable errorParseFailure) { // cause elasticsearch also uses AssertionError
 
 			try {
 				return Mono.error(BytesRestResponse.errorFromXContent(createParser(mediaType, content)));

src/main/java/org/springframework/data/elasticsearch/config/AbstractReactiveElasticsearchConfiguration.java

@@ -47,7 +47,7 @@ public abstract class AbstractReactiveElasticsearchConfiguration extends Elastic
 	 * @return never {@literal null}.
 	 */
 	@Bean
-	public ReactiveElasticsearchOperations reactiveElasticsearchOperations() {
+	public ReactiveElasticsearchOperations reactiveElasticsearchTemplate() {
 
 		ReactiveElasticsearchTemplate template = new ReactiveElasticsearchTemplate(reactiveElasticsearchClient(),
 				elasticsearchConverter());

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

@@ -22,6 +22,8 @@ import org.elasticsearch.ElasticsearchException;
 import org.springframework.dao.DataAccessException;
 import org.springframework.dao.DataAccessResourceFailureException;
 import org.springframework.dao.support.PersistenceExceptionTranslator;
+import org.springframework.data.elasticsearch.NoSuchIndexException;
+import org.springframework.util.CollectionUtils;
 
 /**
  * @author Christoph Strobl
@@ -33,15 +35,22 @@ public class ElasticsearchExceptionTranslator implements PersistenceExceptionTra
 	public DataAccessException translateExceptionIfPossible(RuntimeException ex) {
 
 		if (ex instanceof ElasticsearchException) {
-			// TODO: exception translation
-			ElasticsearchException elasticsearchExption = (ElasticsearchException) ex;
-//			elasticsearchExption.get
+
+			ElasticsearchException elasticsearchException = (ElasticsearchException) ex;
+
+			if (!indexAvailable(elasticsearchException)) {
+				return new NoSuchIndexException(elasticsearchException.getMetadata("es.index").toString(), ex);
+			}
 		}
 
-		if(ex.getCause() instanceof ConnectException) {
+		if (ex.getCause() instanceof ConnectException) {
 			return new DataAccessResourceFailureException(ex.getMessage(), ex);
 		}
 
 		return null;
 	}
+
+	private boolean indexAvailable(ElasticsearchException ex) {
+		return !CollectionUtils.contains(ex.getMetadata("es.index_uuid").iterator(), "_na_");
+	}
 }

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

@@ -22,6 +22,7 @@ import org.elasticsearch.index.query.QueryBuilders;
 import org.reactivestreams.Publisher;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.elasticsearch.client.reactive.ReactiveElasticsearchClient;
+import org.springframework.data.elasticsearch.core.convert.ElasticsearchConverter;
 import org.springframework.data.elasticsearch.core.query.Query;
 import org.springframework.data.elasticsearch.core.query.StringQuery;
 import org.springframework.lang.Nullable;
@@ -451,6 +452,13 @@ public interface ReactiveElasticsearchOperations {
 	 */
 	Mono<Long> deleteBy(Query query, Class<?> entityType, @Nullable String index, @Nullable String type);
 
+	/**
+	 * Get the {@link ElasticsearchConverter} used.
+	 *
+	 * @return never {@literal null}
+	 */
+	ElasticsearchConverter getElasticsearchConverter();
+
 	/**
 	 * Callback interface to be used with {@link #execute(ClientCallback)} for operating directly on
 	 * {@link ReactiveElasticsearchClient}.

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

@@ -52,6 +52,7 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
+import org.springframework.data.elasticsearch.NoSuchIndexException;
 import org.springframework.data.elasticsearch.client.reactive.ReactiveElasticsearchClient;
 import org.springframework.data.elasticsearch.core.EntityOperations.AdaptibleEntity;
 import org.springframework.data.elasticsearch.core.EntityOperations.Entity;
@@ -62,6 +63,7 @@ import org.springframework.data.elasticsearch.core.mapping.ElasticsearchPersiste
 import org.springframework.data.elasticsearch.core.mapping.ElasticsearchPersistentProperty;
 import org.springframework.data.elasticsearch.core.mapping.SimpleElasticsearchMappingContext;
 import org.springframework.data.elasticsearch.core.query.CriteriaQuery;
+import org.springframework.data.elasticsearch.core.query.NativeSearchQuery;
 import org.springframework.data.elasticsearch.core.query.Query;
 import org.springframework.data.elasticsearch.core.query.SearchQuery;
 import org.springframework.data.elasticsearch.core.query.StringQuery;
@@ -69,7 +71,6 @@ import org.springframework.data.mapping.context.MappingContext;
 import org.springframework.http.HttpStatus;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
-import org.springframework.util.ObjectUtils;
 
 /**
  * @author Christoph Strobl
@@ -141,7 +142,7 @@ public class ReactiveElasticsearchTemplate implements ReactiveElasticsearchOpera
 			IndexCoordinates indexCoordinates = operations.determineIndex(entity, index, type);
 
 			IndexRequest request = id != null
-					? new IndexRequest(indexCoordinates.getIndexName(), indexCoordinates.getTypeName(), id.toString())
+					? new IndexRequest(indexCoordinates.getIndexName(), indexCoordinates.getTypeName(), converter.convertId(id))
 					: new IndexRequest(indexCoordinates.getIndexName(), indexCoordinates.getTypeName());
 
 			try {
@@ -163,7 +164,7 @@ public class ReactiveElasticsearchTemplate implements ReactiveElasticsearchOpera
 
 				Object parentId = entity.getParentId();
 				if (parentId != null) {
-					request.parent(parentId.toString());
+					request.parent(converter.convertId(parentId));
 				}
 			}
 
@@ -307,7 +308,7 @@ public class ReactiveElasticsearchTemplate implements ReactiveElasticsearchOpera
 
 		Entity<?> elasticsearchEntity = operations.forEntity(entity);
 
-		return Mono.defer(() -> doDeleteById(entity, ObjectUtils.nullSafeToString(elasticsearchEntity.getId()),
+		return Mono.defer(() -> doDeleteById(entity, converter.convertId(elasticsearchEntity.getId()),
 				elasticsearchEntity.getPersistentEntity(), index, type));
 	}
 
@@ -384,6 +385,15 @@ public class ReactiveElasticsearchTemplate implements ReactiveElasticsearchOpera
 		this.indicesOptions = indicesOptions;
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.elasticsearch.core.ReactiveElasticsearchOperations#getElasticsearchConverter()
+	 */
+	@Override
+	public ElasticsearchConverter getElasticsearchConverter() {
+		return converter;
+	}
+
 	// Customization Hooks
 
 	/**
@@ -491,7 +501,9 @@ public class ReactiveElasticsearchTemplate implements ReactiveElasticsearchOpera
 	 * @return a {@link Mono} emitting the result of the operation.
 	 */
 	protected Mono<GetResult> doFindById(GetRequest request) {
-		return Mono.from(execute(client -> client.get(request)));
+
+		return Mono.from(execute(client -> client.get(request))) //
+				.onErrorResume(NoSuchIndexException.class, it -> Mono.empty());
 	}
 
 	/**
@@ -501,7 +513,9 @@ public class ReactiveElasticsearchTemplate implements ReactiveElasticsearchOpera
 	 * @return a {@link Mono} emitting the result of the operation.
 	 */
 	protected Mono<Boolean> doExists(GetRequest request) {
-		return Mono.from(execute(client -> client.exists(request)));
+
+		return Mono.from(execute(client -> client.exists(request))) //
+				.onErrorReturn(NoSuchIndexException.class, false);
 	}
 
 	/**
@@ -516,7 +530,8 @@ public class ReactiveElasticsearchTemplate implements ReactiveElasticsearchOpera
 			QUERY_LOGGER.debug("Executing doFind: {}", request);
 		}
 
-		return Flux.from(execute(client -> client.search(request)));
+		return Flux.from(execute(client -> client.search(request))) //
+				.onErrorResume(NoSuchIndexException.class, it -> Mono.empty());
 	}
 
 	/**
@@ -531,7 +546,8 @@ public class ReactiveElasticsearchTemplate implements ReactiveElasticsearchOpera
 			QUERY_LOGGER.debug("Executing doScan: {}", request);
 		}
 
-		return Flux.from(execute(client -> client.scroll(request)));
+		return Flux.from(execute(client -> client.scroll(request))) //
+				.onErrorResume(NoSuchIndexException.class, it -> Mono.empty());
 	}
 
 	/**
@@ -551,7 +567,8 @@ public class ReactiveElasticsearchTemplate implements ReactiveElasticsearchOpera
 					}
 
 					return Mono.just(it.getId());
-				});
+				}) //
+				.onErrorResume(NoSuchIndexException.class, it -> Mono.empty());
 	}
 
 	/**
@@ -561,7 +578,9 @@ public class ReactiveElasticsearchTemplate implements ReactiveElasticsearchOpera
 	 * @return a {@link Mono} emitting the result of the operation.
 	 */
 	protected Mono<BulkByScrollResponse> doDeleteBy(DeleteByQueryRequest request) {
-		return Mono.from(execute(client -> client.deleteBy(request)));
+
+		return Mono.from(execute(client -> client.deleteBy(request))) //
+				.onErrorResume(NoSuchIndexException.class, it -> Mono.empty());
 	}
 
 	// private helpers
@@ -621,7 +640,11 @@ public class ReactiveElasticsearchTemplate implements ReactiveElasticsearchOpera
 			elasticsearchQuery = new CriteriaQueryProcessor().createQueryFromCriteria(((CriteriaQuery) query).getCriteria());
 		} else if (query instanceof StringQuery) {
 			elasticsearchQuery = new WrapperQueryBuilder(((StringQuery) query).getSource());
-		} else {
+		} else if (query instanceof NativeSearchQuery) {
+			elasticsearchQuery = ((NativeSearchQuery) query).getQuery();
+		}
+
+		else {
 			throw new IllegalArgumentException(String.format("Unknown query type '%s'.", query.getClass()));
 		}
 

src/main/java/org/springframework/data/elasticsearch/core/convert/ElasticsearchConverter.java

@@ -19,14 +19,15 @@ import org.springframework.core.convert.ConversionService;
 import org.springframework.data.elasticsearch.core.mapping.ElasticsearchPersistentEntity;
 import org.springframework.data.elasticsearch.core.mapping.ElasticsearchPersistentProperty;
 import org.springframework.data.mapping.context.MappingContext;
+import org.springframework.util.Assert;
 
 /**
  * ElasticsearchConverter
  *
  * @author Rizwan Idrees
  * @author Mohsin Husen
+ * @author Christoph Strobl
  */
-
 public interface ElasticsearchConverter {
 
 	/**
@@ -42,4 +43,22 @@ public interface ElasticsearchConverter {
 	 * @return never {@literal null}.
 	 */
 	ConversionService getConversionService();
+
+	/**
+	 * Convert a given {@literal idValue} to its {@link String} representation taking potentially registered
+	 * {@link org.springframework.core.convert.converter.Converter Converters} into account.
+	 *
+	 * @param idValue must not be {@literal null}.
+	 * @return never {@literal null}.
+	 * @since 3.2
+	 */
+	default String convertId(Object idValue) {
+
+		Assert.notNull(idValue, "idValue must not be null!");
+		if (!getConversionService().canConvert(idValue.getClass(), String.class)) {
+			return idValue.toString();
+		}
+
+		return getConversionService().convert(idValue, String.class);
+	}
 }

src/main/java/org/springframework/data/elasticsearch/core/mapping/SimpleElasticsearchPersistentEntity.java

@@ -100,14 +100,24 @@ public class SimpleElasticsearchPersistentEntity<T> extends BasicPersistentEntit
 
 	@Override
 	public String getIndexName() {
-		Expression expression = parser.parseExpression(indexName, ParserContext.TEMPLATE_EXPRESSION);
-		return expression.getValue(context, String.class);
+
+		if(indexName != null) {
+			Expression expression = parser.parseExpression(indexName, ParserContext.TEMPLATE_EXPRESSION);
+			return expression.getValue(context, String.class);
+		}
+
+		return getTypeInformation().getType().getSimpleName();
 	}
 
 	@Override
 	public String getIndexType() {
-		Expression expression = parser.parseExpression(indexType, ParserContext.TEMPLATE_EXPRESSION);
-		return expression.getValue(context, String.class);
+
+		if(indexType != null) {
+			Expression expression = parser.parseExpression(indexType, ParserContext.TEMPLATE_EXPRESSION);
+			return expression.getValue(context, String.class);
+		}
+
+		return "";
 	}
 
 	@Override

src/main/java/org/springframework/data/elasticsearch/core/query/Query.java

@@ -15,10 +15,13 @@
  */
 package org.springframework.data.elasticsearch.core.query;
 
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
+
 import org.elasticsearch.action.search.SearchType;
 import org.elasticsearch.action.support.IndicesOptions;
+import org.elasticsearch.index.query.QueryBuilders;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
@@ -31,12 +34,24 @@ import org.springframework.data.domain.Sort;
  * @author Mark Paluch
  * @author Alen Turkovic
  * @author Sascha Woo
+ * @author Christoph Strobl
  */
 public interface Query {
 
 	int DEFAULT_PAGE_SIZE = 10;
 	Pageable DEFAULT_PAGE = PageRequest.of(0, DEFAULT_PAGE_SIZE);
 
+	/**
+	 * Get get a {@link Query} that matches all documents in the index.
+	 *
+	 * @return new instance of {@link Query}.
+	 * @since 3.2
+	 * @see QueryBuilders#matchAllQuery()
+	 */
+	static Query findAll() {
+		return new StringQuery(QueryBuilders.matchAllQuery().toString());
+	}
+
 	/**
 	 * restrict result to entries on given page. Corresponds to the 'start' and 'rows' parameter in elasticsearch
 	 *

src/main/java/org/springframework/data/elasticsearch/repository/ReactiveElasticsearchRepository.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository;
+
+import org.springframework.data.repository.NoRepositoryBean;
+import org.springframework.data.repository.reactive.ReactiveSortingRepository;
+
+/**
+ * Elasticsearch specific {@link org.springframework.data.repository.Repository} interface with reactive support.
+ *
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+@NoRepositoryBean
+public interface ReactiveElasticsearchRepository<T, ID> extends ReactiveSortingRepository<T, ID> {
+
+}

src/main/java/org/springframework/data/elasticsearch/repository/config/ElasticsearchRepositoryConfigExtension.java

@@ -29,6 +29,7 @@ import org.springframework.data.elasticsearch.repository.support.ElasticsearchRe
 import org.springframework.data.repository.config.AnnotationRepositoryConfigurationSource;
 import org.springframework.data.repository.config.RepositoryConfigurationExtensionSupport;
 import org.springframework.data.repository.config.XmlRepositoryConfigurationSource;
+import org.springframework.data.repository.core.RepositoryMetadata;
 import org.w3c.dom.Element;
 
 /**
@@ -39,6 +40,7 @@ import org.w3c.dom.Element;
  * @author Rizwan Idrees
  * @author Mohsin Husen
  * @author Mark Paluch
+ * @author Christoph Strobl
  */
 public class ElasticsearchRepositoryConfigExtension extends RepositoryConfigurationExtensionSupport {
 
@@ -88,7 +90,7 @@ public class ElasticsearchRepositoryConfigExtension extends RepositoryConfigurat
 	 */
 	@Override
 	protected Collection<Class<? extends Annotation>> getIdentifyingAnnotations() {
-		return Collections.<Class<? extends Annotation>> singleton(Document.class);
+		return Collections.singleton(Document.class);
 	}
 
 	/*
@@ -97,6 +99,15 @@ public class ElasticsearchRepositoryConfigExtension extends RepositoryConfigurat
 	*/
 	@Override
 	protected Collection<Class<?>> getIdentifyingTypes() {
-		return Arrays.<Class<?>> asList(ElasticsearchRepository.class, ElasticsearchCrudRepository.class);
+		return Arrays.asList(ElasticsearchRepository.class, ElasticsearchCrudRepository.class);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.config.RepositoryConfigurationExtensionSupport#useRepositoryConfiguration(org.springframework.data.repository.core.RepositoryMetadata)
+	 */
+	@Override
+	protected boolean useRepositoryConfiguration(RepositoryMetadata metadata) {
+		return !metadata.isReactiveRepository();
 	}
 }

src/main/java/org/springframework/data/elasticsearch/repository/config/EnableReactiveElasticsearchRepositories.java

@@ -0,0 +1,130 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.config;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.springframework.beans.factory.FactoryBean;
+import org.springframework.context.annotation.ComponentScan.Filter;
+import org.springframework.context.annotation.Import;
+import org.springframework.data.elasticsearch.repository.support.ReactiveElasticsearchRepositoryFactoryBean;
+import org.springframework.data.repository.config.DefaultRepositoryBaseClass;
+import org.springframework.data.repository.query.QueryLookupStrategy;
+import org.springframework.data.repository.query.QueryLookupStrategy.Key;
+
+/**
+ * Annotation to activate reactive Elasticsearch repositories. If no base package is configured through either
+ * {@link #value()}, {@link #basePackages()} or {@link #basePackageClasses()} it will trigger scanning of the package of
+ * annotated class.
+ *
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+@Inherited
+@Import(ReactiveElasticsearchRepositoriesRegistrar.class)
+public @interface EnableReactiveElasticsearchRepositories {
+
+	/**
+	 * Alias for the {@link #basePackages()} attribute.
+	 */
+	String[] value() default {};
+
+	/**
+	 * Base packages to scan for annotated components. {@link #value()} is an alias for (and mutually exclusive with) this
+	 * attribute. Use {@link #basePackageClasses()} for a type-safe alternative to String-based package names.
+	 */
+	String[] basePackages() default {};
+
+	/**
+	 * Type-safe alternative to {@link #basePackages()} for specifying the packages to scan for annotated components. The
+	 * package of each class specified will be scanned. Consider creating a special no-op marker class or interface in
+	 * each package that serves no purpose other than being referenced by this attribute.
+	 */
+	Class<?>[] basePackageClasses() default {};
+
+	/**
+	 * Specifies which types are eligible for component scanning. Further narrows the set of candidate components from
+	 * everything in {@link #basePackages()} to everything in the base packages that matches the given filter or filters.
+	 */
+	Filter[] includeFilters() default {};
+
+	/**
+	 * Specifies which types are not eligible for component scanning.
+	 */
+	Filter[] excludeFilters() default {};
+
+	/**
+	 * Returns the postfix to be used when looking up custom repository implementations. Defaults to {@literal Impl}. So
+	 * for a repository named {@code PersonRepository} the corresponding implementation class will be looked up scanning
+	 * for {@code PersonRepositoryImpl}.
+	 *
+	 * @return
+	 */
+	String repositoryImplementationPostfix() default "Impl";
+
+	/**
+	 * Configures the location of where to find the Spring Data named queries properties file. Will default to
+	 * {@code META-INF/elasticsearch-named-queries.properties}.
+	 *
+	 * @return
+	 */
+	String namedQueriesLocation() default "";
+
+	/**
+	 * Returns the key of the {@link QueryLookupStrategy} to be used for lookup queries for query methods. Defaults to
+	 * {@link Key#CREATE_IF_NOT_FOUND}.
+	 *
+	 * @return
+	 */
+	Key queryLookupStrategy() default Key.CREATE_IF_NOT_FOUND;
+
+	/**
+	 * Returns the {@link FactoryBean} class to be used for each repository instance. Defaults to
+	 * {@link ReactiveElasticsearchRepositoryFactoryBean}.
+	 *
+	 * @return
+	 */
+	Class<?> repositoryFactoryBeanClass() default ReactiveElasticsearchRepositoryFactoryBean.class;
+
+	/**
+	 * Configure the repository base class to be used to create repository proxies for this particular configuration.
+	 *
+	 * @return
+	 */
+	Class<?> repositoryBaseClass() default DefaultRepositoryBaseClass.class;
+
+	/**
+	 * Configures the name of the {@link org.springframework.data.elasticsearch.core.ReactiveElasticsearchOperations} bean
+	 * to be used with the repositories detected.
+	 *
+	 * @return
+	 */
+	String reactiveElasticsearchTemplateRef() default "reactiveElasticsearchTemplate";
+
+	/**
+	 * Configures whether nested repository-interfaces (e.g. defined as inner classes) should be discovered by the
+	 * repositories infrastructure.
+	 */
+	boolean considerNestedRepositories() default false;
+}

src/main/java/org/springframework/data/elasticsearch/repository/config/ReactiveElasticsearchRepositoriesRegistrar.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.config;
+
+import java.lang.annotation.Annotation;
+
+import org.springframework.data.repository.config.RepositoryBeanDefinitionRegistrarSupport;
+import org.springframework.data.repository.config.RepositoryConfigurationExtension;
+
+/**
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+class ReactiveElasticsearchRepositoriesRegistrar extends RepositoryBeanDefinitionRegistrarSupport {
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.config.RepositoryBeanDefinitionRegistrarSupport#getAnnotation()
+	 */
+	@Override
+	protected Class<? extends Annotation> getAnnotation() {
+		return EnableReactiveElasticsearchRepositories.class;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.config.RepositoryBeanDefinitionRegistrarSupport#getExtension()
+	 */
+	@Override
+	protected RepositoryConfigurationExtension getExtension() {
+		return new ReactiveElasticsearchRepositoryConfigurationExtension();
+	}
+}

src/main/java/org/springframework/data/elasticsearch/repository/config/ReactiveElasticsearchRepositoryConfigurationExtension.java

@@ -0,0 +1,98 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.config;
+
+import java.util.Collection;
+import java.util.Collections;
+
+import org.springframework.beans.factory.support.BeanDefinitionBuilder;
+import org.springframework.core.annotation.AnnotationAttributes;
+import org.springframework.data.config.ParsingUtils;
+import org.springframework.data.elasticsearch.repository.ReactiveElasticsearchRepository;
+import org.springframework.data.elasticsearch.repository.support.ReactiveElasticsearchRepositoryFactoryBean;
+import org.springframework.data.repository.config.AnnotationRepositoryConfigurationSource;
+import org.springframework.data.repository.config.XmlRepositoryConfigurationSource;
+import org.springframework.data.repository.core.RepositoryMetadata;
+import org.w3c.dom.Element;
+
+/**
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+public class ReactiveElasticsearchRepositoryConfigurationExtension extends ElasticsearchRepositoryConfigExtension {
+
+	private static final String ELASTICSEARCH_TEMPLATE_REF = "reactive-elasticsearch-template-ref";
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.config.RepositoryConfigurationExtensionSupport#getModuleName()
+	 */
+	@Override
+	public String getModuleName() {
+		return "Reactive Elasticsearch";
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.config.RepositoryConfigurationExtension#getRepositoryFactoryClassName()
+	 */
+	public String getRepositoryFactoryClassName() {
+		return ReactiveElasticsearchRepositoryFactoryBean.class.getName();
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.config.RepositoryConfigurationExtensionSupport#getIdentifyingTypes()
+	 */
+	@Override
+	protected Collection<Class<?>> getIdentifyingTypes() {
+		return Collections.singleton(ReactiveElasticsearchRepository.class);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.config.RepositoryConfigurationExtensionSupport#postProcess(org.springframework.beans.factory.support.BeanDefinitionBuilder, org.springframework.data.repository.config.XmlRepositoryConfigurationSource)
+	 */
+	@Override
+	public void postProcess(BeanDefinitionBuilder builder, XmlRepositoryConfigurationSource config) {
+
+		Element element = config.getElement();
+
+		ParsingUtils.setPropertyReference(builder, element, ELASTICSEARCH_TEMPLATE_REF, "reactiveElasticsearchOperations");
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.config.RepositoryConfigurationExtensionSupport#postProcess(org.springframework.beans.factory.support.BeanDefinitionBuilder, org.springframework.data.repository.config.AnnotationRepositoryConfigurationSource)
+	 */
+	@Override
+	public void postProcess(BeanDefinitionBuilder builder, AnnotationRepositoryConfigurationSource config) {
+
+		AnnotationAttributes attributes = config.getAttributes();
+
+		builder.addPropertyReference("reactiveElasticsearchOperations",
+				attributes.getString("reactiveElasticsearchTemplateRef"));
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.config.RepositoryConfigurationExtensionSupport#useRepositoryConfiguration(org.springframework.data.repository.core.RepositoryMetadata)
+	 */
+	@Override
+	protected boolean useRepositoryConfiguration(RepositoryMetadata metadata) {
+		return metadata.isReactiveRepository();
+	}
+}

src/main/java/org/springframework/data/elasticsearch/repository/query/AbstractReactiveElasticsearchRepositoryQuery.java

@@ -0,0 +1,141 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.query;
+
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+import org.reactivestreams.Publisher;
+import org.springframework.core.convert.converter.Converter;
+import org.springframework.data.elasticsearch.core.ReactiveElasticsearchOperations;
+import org.springframework.data.elasticsearch.core.mapping.ElasticsearchPersistentEntity;
+import org.springframework.data.elasticsearch.core.mapping.ElasticsearchPersistentProperty;
+import org.springframework.data.elasticsearch.core.query.Query;
+import org.springframework.data.elasticsearch.repository.query.ReactiveElasticsearchQueryExecution.ResultProcessingConverter;
+import org.springframework.data.elasticsearch.repository.query.ReactiveElasticsearchQueryExecution.ResultProcessingExecution;
+import org.springframework.data.mapping.context.MappingContext;
+import org.springframework.data.repository.query.ParameterAccessor;
+import org.springframework.data.repository.query.QueryMethod;
+import org.springframework.data.repository.query.RepositoryQuery;
+import org.springframework.data.repository.query.ResultProcessor;
+
+/**
+ * AbstractElasticsearchRepositoryQuery
+ *
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+abstract class AbstractReactiveElasticsearchRepositoryQuery implements RepositoryQuery {
+
+	private final ReactiveElasticsearchQueryMethod queryMethod;
+	private final ReactiveElasticsearchOperations elasticsearchOperations;
+
+	AbstractReactiveElasticsearchRepositoryQuery(ReactiveElasticsearchQueryMethod queryMethod,
+			ReactiveElasticsearchOperations elasticsearchOperations) {
+
+		this.queryMethod = queryMethod;
+		this.elasticsearchOperations = elasticsearchOperations;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.query.RepositoryQuery#execute(java.lang.Object[])
+	 */
+	public Object execute(Object[] parameters) {
+
+		return queryMethod.hasReactiveWrapperParameter() ? executeDeferred(parameters)
+				: execute(new ReactiveElasticsearchParametersParameterAccessor(queryMethod, parameters));
+	}
+
+	private Object executeDeferred(Object[] parameters) {
+
+		ReactiveElasticsearchParametersParameterAccessor parameterAccessor = new ReactiveElasticsearchParametersParameterAccessor(
+				queryMethod, parameters);
+
+		if (getQueryMethod().isCollectionQuery()) {
+			return Flux.defer(() -> (Publisher<Object>) execute(parameterAccessor));
+		}
+
+		return Mono.defer(() -> (Mono<Object>) execute(parameterAccessor));
+	}
+
+	private Object execute(ElasticsearchParameterAccessor parameterAccessor) {
+
+		ResultProcessor processor = queryMethod.getResultProcessor().withDynamicProjection(parameterAccessor);
+
+		Query query = createQuery(
+				new ConvertingParameterAccessor(elasticsearchOperations.getElasticsearchConverter(), parameterAccessor));
+
+		Class<?> typeToRead = processor.getReturnedType().getTypeToRead();
+		String indexName = queryMethod.getEntityInformation().getIndexName();
+		String indexTypeName = queryMethod.getEntityInformation().getIndexTypeName();
+
+		ReactiveElasticsearchQueryExecution execution = getExecution(parameterAccessor,
+				new ResultProcessingConverter(processor, elasticsearchOperations));
+
+		return execution.execute(query, processor.getReturnedType().getDomainType(), indexName, indexTypeName, typeToRead);
+	}
+
+	private ReactiveElasticsearchQueryExecution getExecution(ElasticsearchParameterAccessor accessor,
+			Converter<Object, Object> resultProcessing) {
+		return new ResultProcessingExecution(getExecutionToWrap(accessor, elasticsearchOperations), resultProcessing);
+	}
+
+	/**
+	 * Creates a {@link Query} instance using the given {@link ParameterAccessor}
+	 *
+	 * @param accessor must not be {@literal null}.
+	 * @return
+	 */
+	protected abstract Query createQuery(ElasticsearchParameterAccessor accessor);
+
+	private ReactiveElasticsearchQueryExecution getExecutionToWrap(ElasticsearchParameterAccessor accessor,
+			ReactiveElasticsearchOperations operations) {
+
+		if (isDeleteQuery()) {
+			return (q, t, i, it, tt) -> operations.deleteBy(q, t, i, it);
+		} else if (isCountQuery()) {
+			return (q, t, i, it, tt) -> operations.count(q, t, i, it);
+		} else if (isExistsQuery()) {
+			return (q, t, i, it, tt) -> operations.count(q, t, i, it).map(count -> count > 0);
+		} else if (queryMethod.isCollectionQuery()) {
+			return (q, t, i, it, tt) -> operations.find(q.setPageable(accessor.getPageable()), t, i, it, tt);
+		} else {
+			return (q, t, i, it, tt) -> operations.find(q, t, i, it, tt);
+		}
+	}
+
+	abstract boolean isDeleteQuery();
+
+	abstract boolean isCountQuery();
+
+	abstract boolean isExistsQuery();
+
+	abstract boolean isLimiting();
+
+	@Override
+	public QueryMethod getQueryMethod() {
+		return queryMethod;
+	}
+
+	protected ReactiveElasticsearchOperations getElasticsearchOperations() {
+		return elasticsearchOperations;
+	}
+
+	protected MappingContext<? extends ElasticsearchPersistentEntity<?>, ElasticsearchPersistentProperty> getMappingContext() {
+		return elasticsearchOperations.getElasticsearchConverter().getMappingContext();
+	}
+}

src/main/java/org/springframework/data/elasticsearch/repository/query/ConvertingParameterAccessor.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.query;
+
+import java.util.Iterator;
+import java.util.Optional;
+
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.domain.Sort;
+import org.springframework.data.elasticsearch.core.convert.ElasticsearchConverter;
+import org.springframework.lang.Nullable;
+
+/**
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+public class ConvertingParameterAccessor implements ElasticsearchParameterAccessor {
+
+	private final ElasticsearchConverter converter;
+	private final ElasticsearchParameterAccessor delegate;
+
+	public ConvertingParameterAccessor(ElasticsearchConverter converter, ElasticsearchParameterAccessor delegate) {
+
+		this.converter = converter;
+		this.delegate = delegate;
+	}
+
+	@Override
+	public Object[] getValues() {
+		return delegate.getValues();
+	}
+
+	@Override
+	public Pageable getPageable() {
+		return delegate.getPageable();
+	}
+
+	@Override
+	public Sort getSort() {
+		return delegate.getSort();
+	}
+
+	@Override
+	public Optional<Class<?>> getDynamicProjection() {
+		return delegate.getDynamicProjection();
+	}
+
+	@Override
+	public Object getBindableValue(int index) {
+		return getConvertedValue(delegate.getBindableValue(index));
+	}
+
+	@Override
+	public boolean hasBindableNullValue() {
+		return delegate.hasBindableNullValue();
+	}
+
+	@Override
+	public Iterator<Object> iterator() {
+		return delegate.iterator();
+	}
+
+	@Nullable
+	private Object getConvertedValue(Object value) {
+
+		if (value == null) {
+			return "null";
+		}
+
+		if (converter.getConversionService().canConvert(value.getClass(), String.class)) {
+			return converter.getConversionService().convert(value, String.class);
+		}
+
+		return value.toString();
+	}
+}

src/main/java/org/springframework/data/elasticsearch/repository/query/ElasticsearchEntityMetadata.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.query;
+
+import org.springframework.data.repository.core.EntityMetadata;
+
+/**
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+public interface ElasticsearchEntityMetadata<T> extends EntityMetadata<T> {
+
+	String getIndexName();
+
+	String getIndexTypeName();
+}

src/main/java/org/springframework/data/elasticsearch/repository/query/ElasticsearchParameterAccessor.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.query;
+
+import org.springframework.data.repository.query.ParameterAccessor;
+
+/**
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+public interface ElasticsearchParameterAccessor extends ParameterAccessor {
+
+	/**
+	 * Returns the raw parameter values of the underlying query method.
+	 *
+	 * @return
+	 */
+	Object[] getValues();
+}

src/main/java/org/springframework/data/elasticsearch/repository/query/ElasticsearchParameters.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.query;
+
+import java.lang.reflect.Method;
+import java.util.List;
+
+import org.springframework.core.MethodParameter;
+import org.springframework.data.elasticsearch.repository.query.ElasticsearchParameters.ElasticsearchParameter;
+import org.springframework.data.geo.Distance;
+import org.springframework.data.repository.query.Parameter;
+import org.springframework.data.repository.query.Parameters;
+
+/**
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+public class ElasticsearchParameters extends Parameters<ElasticsearchParameters, ElasticsearchParameter> {
+
+	public ElasticsearchParameters(Method method) {
+		super(method);
+	}
+
+	private ElasticsearchParameters(List<ElasticsearchParameter> parameters) {
+		super(parameters);
+	}
+
+	@Override
+	protected ElasticsearchParameter createParameter(MethodParameter parameter) {
+		return new ElasticsearchParameter(parameter);
+	}
+
+	@Override
+	protected ElasticsearchParameters createFrom(List<ElasticsearchParameter> parameters) {
+		return new ElasticsearchParameters(parameters);
+	}
+
+	/**
+	 * Custom {@link Parameter} implementation adding parameters of type {@link Distance} to the special ones.
+	 *
+	 * @author Christoph Strobl
+	 */
+	class ElasticsearchParameter extends Parameter {
+
+		private final MethodParameter parameter;
+
+		/**
+		 * Creates a new {@link ElasticsearchParameter}.
+		 *
+		 * @param parameter must not be {@literal null}.
+		 */
+		ElasticsearchParameter(MethodParameter parameter) {
+
+			super(parameter);
+			this.parameter = parameter;
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.repository.query.Parameter#isSpecialParameter()
+		 */
+		@Override
+		public boolean isSpecialParameter() {
+			return super.isSpecialParameter();
+		}
+	}
+}

src/main/java/org/springframework/data/elasticsearch/repository/query/ElasticsearchParametersParameterAccessor.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.query;
+
+import java.util.Arrays;
+import java.util.List;
+
+import org.springframework.data.repository.query.ParametersParameterAccessor;
+
+/**
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+class ElasticsearchParametersParameterAccessor extends ParametersParameterAccessor
+		implements ElasticsearchParameterAccessor {
+
+	private final List<Object> values;
+
+	/**
+	 * Creates a new {@link ElasticsearchParametersParameterAccessor}.
+	 *
+	 * @param method must not be {@literal null}.
+	 * @param values must not be {@literal null}.
+	 */
+	ElasticsearchParametersParameterAccessor(ElasticsearchQueryMethod method, Object[] values) {
+
+		super(method.getParameters(), values);
+		this.values = Arrays.asList(values);
+	}
+
+	@Override
+	public Object[] getValues() {
+		return values.toArray();
+	}
+}

src/main/java/org/springframework/data/elasticsearch/repository/query/ElasticsearchQueryMethod.java

@@ -19,9 +19,15 @@ import java.lang.reflect.Method;
 
 import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.data.elasticsearch.annotations.Query;
+import org.springframework.data.elasticsearch.core.mapping.ElasticsearchPersistentEntity;
+import org.springframework.data.elasticsearch.core.mapping.ElasticsearchPersistentProperty;
+import org.springframework.data.mapping.context.MappingContext;
 import org.springframework.data.projection.ProjectionFactory;
 import org.springframework.data.repository.core.RepositoryMetadata;
 import org.springframework.data.repository.query.QueryMethod;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
 
 /**
  * ElasticsearchQueryMethod
@@ -30,14 +36,23 @@ import org.springframework.data.repository.query.QueryMethod;
  * @author Mohsin Husen
  * @author Oliver Gierke
  * @author Mark Paluch
+ * @author Christoph Strobl
  */
 public class ElasticsearchQueryMethod extends QueryMethod {
 
 	private final Query queryAnnotation;
+	private final MappingContext<? extends ElasticsearchPersistentEntity<?>, ElasticsearchPersistentProperty> mappingContext;
+	private @Nullable ElasticsearchEntityMetadata<?> metadata;
+
+	public ElasticsearchQueryMethod(Method method, RepositoryMetadata metadata, ProjectionFactory factory,
+			MappingContext<? extends ElasticsearchPersistentEntity<?>, ElasticsearchPersistentProperty> mappingContext) {
 
-	public ElasticsearchQueryMethod(Method method, RepositoryMetadata metadata, ProjectionFactory factory) {
 		super(method, metadata, factory);
+
+		Assert.notNull(mappingContext, "MappingContext must not be null!");
+
 		this.queryAnnotation = method.getAnnotation(Query.class);
+		this.mappingContext = mappingContext;
 	}
 
 	public boolean hasAnnotatedQuery() {
@@ -47,4 +62,42 @@ public class ElasticsearchQueryMethod extends QueryMethod {
 	public String getAnnotatedQuery() {
 		return (String) AnnotationUtils.getValue(queryAnnotation, "value");
 	}
+
+	/**
+	 * @return the {@link ElasticsearchEntityMetadata} for the query methods {@link #getReturnedObjectType() return type}.
+	 * @since 3.2
+	 */
+	public ElasticsearchEntityMetadata<?> getEntityInformation() {
+
+		if (metadata == null) {
+
+			Class<?> returnedObjectType = getReturnedObjectType();
+			Class<?> domainClass = getDomainClass();
+
+			if (ClassUtils.isPrimitiveOrWrapper(returnedObjectType)) {
+
+				this.metadata = new SimpleElasticsearchEntityMetadata<>((Class<Object>) domainClass,
+						mappingContext.getRequiredPersistentEntity(domainClass));
+
+			} else {
+
+				ElasticsearchPersistentEntity<?> returnedEntity = mappingContext.getPersistentEntity(returnedObjectType);
+				ElasticsearchPersistentEntity<?> managedEntity = mappingContext.getRequiredPersistentEntity(domainClass);
+				returnedEntity = returnedEntity == null || returnedEntity.getType().isInterface() ? managedEntity
+						: returnedEntity;
+				ElasticsearchPersistentEntity<?> collectionEntity = domainClass.isAssignableFrom(returnedObjectType)
+						? returnedEntity
+						: managedEntity;
+
+				this.metadata = new SimpleElasticsearchEntityMetadata<>((Class<Object>) returnedEntity.getType(),
+						collectionEntity);
+			}
+		}
+
+		return this.metadata;
+	}
+
+	protected MappingContext<? extends ElasticsearchPersistentEntity<?>, ElasticsearchPersistentProperty> getMappingContext() {
+		return mappingContext;
+	}
 }

src/main/java/org/springframework/data/elasticsearch/repository/query/ReactiveElasticsearchParametersParameterAccessor.java

@@ -0,0 +1,101 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.query;
+
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+import reactor.core.publisher.MonoProcessor;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.data.repository.util.ReactiveWrapperConverters;
+import org.springframework.data.repository.util.ReactiveWrappers;
+
+/**
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+class ReactiveElasticsearchParametersParameterAccessor extends ElasticsearchParametersParameterAccessor {
+
+	private final List<MonoProcessor<?>> subscriptions;
+
+	/**
+	 * Creates a new {@link ElasticsearchParametersParameterAccessor}.
+	 *
+	 * @param method must not be {@literal null}.
+	 * @param values must not be {@literal null}.
+	 */
+	ReactiveElasticsearchParametersParameterAccessor(ReactiveElasticsearchQueryMethod method, Object[] values) {
+		super(method, values);
+
+		this.subscriptions = new ArrayList<>(values.length);
+
+		for (int i = 0; i < values.length; i++) {
+
+			Object value = values[i];
+
+			if (value == null || !ReactiveWrappers.supports(value.getClass())) {
+
+				subscriptions.add(null);
+				continue;
+			}
+
+			if (ReactiveWrappers.isSingleValueType(value.getClass())) {
+				subscriptions.add(ReactiveWrapperConverters.toWrapper(value, Mono.class).toProcessor());
+			} else {
+				subscriptions.add(ReactiveWrapperConverters.toWrapper(value, Flux.class).collectList().toProcessor());
+			}
+		}
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.query.ParametersParameterAccessor#getValue(int)
+	 */
+	@SuppressWarnings("unchecked")
+	@Override
+	protected <T> T getValue(int index) {
+
+		if (subscriptions.get(index) != null) {
+			return (T) subscriptions.get(index).block();
+		}
+
+		return super.getValue(index);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.elasticsearch.repository.query.ElasticsearchParametersParameterAccessor#getValues(int)
+	 */
+	@Override
+	public Object[] getValues() {
+
+		Object[] result = new Object[getValues().length];
+		for (int i = 0; i < result.length; i++) {
+			result[i] = getValue(i);
+		}
+		return result;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.query.ParametersParameterAccessor#getBindableValue(int)
+	 */
+	public Object getBindableValue(int index) {
+		return getValue(getParameters().getBindableParameter(index).getIndex());
+	}
+}

src/main/java/org/springframework/data/elasticsearch/repository/query/ReactiveElasticsearchQueryExecution.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.query;
+
+import lombok.NonNull;
+import lombok.RequiredArgsConstructor;
+
+import org.springframework.core.convert.converter.Converter;
+import org.springframework.data.elasticsearch.core.ReactiveElasticsearchOperations;
+import org.springframework.data.elasticsearch.core.query.Query;
+import org.springframework.data.repository.query.ResultProcessor;
+import org.springframework.data.repository.query.ReturnedType;
+import org.springframework.lang.Nullable;
+import org.springframework.util.ClassUtils;
+
+/**
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+public interface ReactiveElasticsearchQueryExecution {
+
+	Object execute(Query query, Class<?> type, String indexName, String indexType, @Nullable Class<?> targetType);
+
+	/**
+	 * An {@link ReactiveElasticsearchQueryExecution} that wraps the results of the given delegate with the given result
+	 * processing.
+	 */
+	@RequiredArgsConstructor
+	final class ResultProcessingExecution implements ReactiveElasticsearchQueryExecution {
+
+		private final @NonNull ReactiveElasticsearchQueryExecution delegate;
+		private final @NonNull Converter<Object, Object> converter;
+
+		@Override
+		public Object execute(Query query, Class<?> type, String indexName, String indexType,
+				@Nullable Class<?> targetType) {
+			return converter.convert(delegate.execute(query, type, indexName, indexType, targetType));
+		}
+	}
+
+	/**
+	 * A {@link Converter} to post-process all source objects using the given {@link ResultProcessor}.
+	 *
+	 * @author Mark Paluch
+	 */
+	@RequiredArgsConstructor
+	final class ResultProcessingConverter implements Converter<Object, Object> {
+
+		private final @NonNull ResultProcessor processor;
+		private final @NonNull ReactiveElasticsearchOperations operations;
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.core.convert.converter.Converter#convert(java.lang.Object)
+		 */
+		@Override
+		public Object convert(Object source) {
+
+			ReturnedType returnedType = processor.getReturnedType();
+
+			if (ClassUtils.isPrimitiveOrWrapper(returnedType.getReturnedType())) {
+				return source;
+			}
+
+			return processor.processResult(source, it -> it);
+		}
+	}
+}

src/main/java/org/springframework/data/elasticsearch/repository/query/ReactiveElasticsearchQueryMethod.java

@@ -0,0 +1,120 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.query;
+
+import static org.springframework.data.repository.util.ClassUtils.*;
+
+import java.lang.reflect.Method;
+
+import org.springframework.dao.InvalidDataAccessApiUsageException;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.domain.Slice;
+import org.springframework.data.domain.Sort;
+import org.springframework.data.elasticsearch.core.mapping.ElasticsearchPersistentEntity;
+import org.springframework.data.elasticsearch.core.mapping.ElasticsearchPersistentProperty;
+import org.springframework.data.elasticsearch.repository.query.ElasticsearchParameters.ElasticsearchParameter;
+import org.springframework.data.mapping.context.MappingContext;
+import org.springframework.data.projection.ProjectionFactory;
+import org.springframework.data.repository.core.RepositoryMetadata;
+import org.springframework.data.repository.util.ReactiveWrapperConverters;
+import org.springframework.data.repository.util.ReactiveWrappers;
+import org.springframework.data.util.ClassTypeInformation;
+import org.springframework.data.util.TypeInformation;
+import org.springframework.util.ClassUtils;
+
+/**
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+public class ReactiveElasticsearchQueryMethod extends ElasticsearchQueryMethod {
+
+	private static final ClassTypeInformation<Page> PAGE_TYPE = ClassTypeInformation.from(Page.class);
+	private static final ClassTypeInformation<Slice> SLICE_TYPE = ClassTypeInformation.from(Slice.class);
+
+	private final Method method;
+
+	public ReactiveElasticsearchQueryMethod(Method method, RepositoryMetadata metadata, ProjectionFactory factory,
+			MappingContext<? extends ElasticsearchPersistentEntity<?>, ElasticsearchPersistentProperty> mappingContext) {
+
+		super(method, metadata, factory, mappingContext);
+		this.method = method;
+
+		if (hasParameterOfType(method, Pageable.class)) {
+
+			TypeInformation<?> returnType = ClassTypeInformation.fromReturnTypeOf(method);
+
+			boolean multiWrapper = ReactiveWrappers.isMultiValueType(returnType.getType());
+			boolean singleWrapperWithWrappedPageableResult = ReactiveWrappers.isSingleValueType(returnType.getType())
+					&& (PAGE_TYPE.isAssignableFrom(returnType.getRequiredComponentType())
+							|| SLICE_TYPE.isAssignableFrom(returnType.getRequiredComponentType()));
+
+			if (singleWrapperWithWrappedPageableResult) {
+				throw new InvalidDataAccessApiUsageException(
+						String.format("'%s.%s' must not use sliced or paged execution. Please use Flux.buffer(size, skip).",
+								ClassUtils.getShortName(method.getDeclaringClass()), method.getName()));
+			}
+
+			if (!multiWrapper) {
+				throw new IllegalStateException(String.format(
+						"Method has to use a either multi-item reactive wrapper return type or a wrapped Page/Slice type. Offending method: %s",
+						method.toString()));
+			}
+
+			if (hasParameterOfType(method, Sort.class)) {
+				throw new IllegalStateException(String.format("Method must not have Pageable *and* Sort parameter. "
+						+ "Use sorting capabilities on Pageble instead! Offending method: %s", method.toString()));
+			}
+		}
+	}
+
+	@Override
+	protected ElasticsearchParameters createParameters(Method method) {
+		return new ElasticsearchParameters(method);
+	}
+
+	/**
+	 * Check if the given {@link org.springframework.data.repository.query.QueryMethod} receives a reactive parameter
+	 * wrapper as one of its parameters.
+	 *
+	 * @return
+	 */
+	public boolean hasReactiveWrapperParameter() {
+
+		for (ElasticsearchParameter param : getParameters()) {
+			if (ReactiveWrapperConverters.supports(param.getType())) {
+				return true;
+			}
+		}
+		return false;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.query.QueryMethod#isStreamQuery()
+	 */
+	@Override
+	public boolean isStreamQuery() {
+
+		// All reactive query methods are streaming.
+		return true;
+	}
+
+	@Override
+	public ElasticsearchParameters getParameters() {
+		return (ElasticsearchParameters) super.getParameters();
+	}
+}

src/main/java/org/springframework/data/elasticsearch/repository/query/ReactiveElasticsearchStringQuery.java

@@ -0,0 +1,92 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.query;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.springframework.data.elasticsearch.core.ReactiveElasticsearchOperations;
+import org.springframework.data.elasticsearch.core.query.StringQuery;
+import org.springframework.data.repository.query.QueryMethodEvaluationContextProvider;
+import org.springframework.expression.spel.standard.SpelExpressionParser;
+import org.springframework.util.ObjectUtils;
+
+/**
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+public class ReactiveElasticsearchStringQuery extends AbstractReactiveElasticsearchRepositoryQuery {
+
+	private static final Pattern PARAMETER_PLACEHOLDER = Pattern.compile("\\?(\\d+)");
+	private final String query;
+
+	public ReactiveElasticsearchStringQuery(ReactiveElasticsearchQueryMethod queryMethod,
+			ReactiveElasticsearchOperations operations, SpelExpressionParser expressionParser,
+			QueryMethodEvaluationContextProvider evaluationContextProvider) {
+
+		this(queryMethod.getAnnotatedQuery(), queryMethod, operations, expressionParser, evaluationContextProvider);
+	}
+
+	public ReactiveElasticsearchStringQuery(String query, ReactiveElasticsearchQueryMethod queryMethod,
+			ReactiveElasticsearchOperations operations, SpelExpressionParser expressionParser,
+			QueryMethodEvaluationContextProvider evaluationContextProvider) {
+
+		super(queryMethod, operations);
+		this.query = query;
+	}
+
+	@Override
+	protected StringQuery createQuery(ElasticsearchParameterAccessor parameterAccessor) {
+		String queryString = replacePlaceholders(this.query, parameterAccessor);
+		return new StringQuery(queryString);
+	}
+
+	private String replacePlaceholders(String input, ElasticsearchParameterAccessor accessor) {
+
+		Matcher matcher = PARAMETER_PLACEHOLDER.matcher(input);
+		String result = input;
+		while (matcher.find()) {
+			String group = matcher.group();
+			int index = Integer.parseInt(matcher.group(1));
+			result = result.replace(group, getParameterWithIndex(accessor, index));
+		}
+		return result;
+	}
+
+	private String getParameterWithIndex(ElasticsearchParameterAccessor accessor, int index) {
+		return ObjectUtils.nullSafeToString(accessor.getBindableValue(index));
+	}
+
+	@Override
+	boolean isCountQuery() {
+		return false;
+	}
+
+	@Override
+	boolean isDeleteQuery() {
+		return false;
+	}
+
+	@Override
+	boolean isExistsQuery() {
+		return false;
+	}
+
+	@Override
+	boolean isLimiting() {
+		return false;
+	}
+}

src/main/java/org/springframework/data/elasticsearch/repository/query/ReactivePartTreeElasticsearchQuery.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.query;
+
+import org.springframework.data.elasticsearch.core.ReactiveElasticsearchOperations;
+import org.springframework.data.elasticsearch.core.query.Query;
+import org.springframework.data.elasticsearch.repository.query.parser.ElasticsearchQueryCreator;
+import org.springframework.data.repository.query.ResultProcessor;
+import org.springframework.data.repository.query.parser.PartTree;
+
+/**
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+public class ReactivePartTreeElasticsearchQuery extends AbstractReactiveElasticsearchRepositoryQuery {
+
+	private final PartTree tree;
+	private final ResultProcessor processor;
+
+	public ReactivePartTreeElasticsearchQuery(ReactiveElasticsearchQueryMethod queryMethod,
+			ReactiveElasticsearchOperations elasticsearchOperations) {
+		super(queryMethod, elasticsearchOperations);
+
+		this.processor = queryMethod.getResultProcessor();
+		this.tree = new PartTree(queryMethod.getName(), processor.getReturnedType().getDomainType());
+	}
+
+	@Override
+	protected Query createQuery(ElasticsearchParameterAccessor accessor) {
+		return new ElasticsearchQueryCreator(tree, accessor, getMappingContext()).createQuery();
+	}
+
+	@Override
+	boolean isLimiting() {
+		return tree.isLimiting();
+	}
+
+	@Override
+	boolean isExistsQuery() {
+		return tree.isExistsProjection();
+	}
+
+	@Override
+	boolean isDeleteQuery() {
+		return tree.isDelete();
+	}
+
+	@Override
+	boolean isCountQuery() {
+		return tree.isCountProjection();
+	}
+}

src/main/java/org/springframework/data/elasticsearch/repository/query/SimpleElasticsearchEntityMetadata.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.query;
+
+import org.springframework.data.elasticsearch.core.mapping.ElasticsearchPersistentEntity;
+import org.springframework.util.Assert;
+
+/**
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+public class SimpleElasticsearchEntityMetadata<T> implements ElasticsearchEntityMetadata<T> {
+
+	private final Class<T> type;
+	private final ElasticsearchPersistentEntity<?> entity;
+
+	public SimpleElasticsearchEntityMetadata(Class<T> type, ElasticsearchPersistentEntity<?> entity) {
+
+		Assert.notNull(type, "Type must not be null!");
+		Assert.notNull(entity, "Entity must not be null!");
+
+		this.type = type;
+		this.entity = entity;
+	}
+
+	@Override
+	public String getIndexName() {
+		return entity.getIndexName();
+	}
+
+	@Override
+	public String getIndexTypeName() {
+		return entity.getIndexType();
+	}
+
+	@Override
+	public Class<T> getJavaType() {
+		return type;
+	}
+}

src/main/java/org/springframework/data/elasticsearch/repository/support/ElasticsearchRepositoryFactory.java

@@ -102,7 +102,8 @@ public class ElasticsearchRepositoryFactory extends RepositoryFactorySupport {
 		public RepositoryQuery resolveQuery(Method method, RepositoryMetadata metadata, ProjectionFactory factory,
 				NamedQueries namedQueries) {
 
-			ElasticsearchQueryMethod queryMethod = new ElasticsearchQueryMethod(method, metadata, factory);
+			ElasticsearchQueryMethod queryMethod = new ElasticsearchQueryMethod(method, metadata, factory,
+					elasticsearchOperations.getElasticsearchConverter().getMappingContext());
 			String namedQueryName = queryMethod.getNamedQueryName();
 
 			if (namedQueries.hasQuery(namedQueryName)) {

src/main/java/org/springframework/data/elasticsearch/repository/support/ReactiveElasticsearchRepositoryFactory.java

@@ -0,0 +1,157 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.support;
+
+import lombok.AccessLevel;
+import lombok.RequiredArgsConstructor;
+
+import java.io.Serializable;
+import java.lang.reflect.Method;
+import java.util.Optional;
+
+import org.springframework.data.elasticsearch.core.ReactiveElasticsearchOperations;
+import org.springframework.data.elasticsearch.core.mapping.ElasticsearchPersistentEntity;
+import org.springframework.data.elasticsearch.core.mapping.ElasticsearchPersistentProperty;
+import org.springframework.data.elasticsearch.repository.query.ReactiveElasticsearchQueryMethod;
+import org.springframework.data.elasticsearch.repository.query.ReactiveElasticsearchStringQuery;
+import org.springframework.data.elasticsearch.repository.query.ReactivePartTreeElasticsearchQuery;
+import org.springframework.data.mapping.context.MappingContext;
+import org.springframework.data.projection.ProjectionFactory;
+import org.springframework.data.repository.core.NamedQueries;
+import org.springframework.data.repository.core.RepositoryInformation;
+import org.springframework.data.repository.core.RepositoryMetadata;
+import org.springframework.data.repository.core.support.ReactiveRepositoryFactorySupport;
+import org.springframework.data.repository.query.QueryLookupStrategy;
+import org.springframework.data.repository.query.QueryLookupStrategy.Key;
+import org.springframework.data.repository.query.QueryMethodEvaluationContextProvider;
+import org.springframework.data.repository.query.RepositoryQuery;
+import org.springframework.expression.spel.standard.SpelExpressionParser;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+
+/**
+ * Factory to create {@link org.springframework.data.elasticsearch.repository.ReactiveElasticsearchRepository}
+ * instances.
+ *
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+public class ReactiveElasticsearchRepositoryFactory extends ReactiveRepositoryFactorySupport {
+
+	private static final SpelExpressionParser EXPRESSION_PARSER = new SpelExpressionParser();
+
+	private final ReactiveElasticsearchOperations operations;
+	private final MappingContext<? extends ElasticsearchPersistentEntity<?>, ElasticsearchPersistentProperty> mappingContext;
+
+	/**
+	 * Creates a new {@link ReactiveElasticsearchRepositoryFactory} with the given
+	 * {@link ReactiveElasticsearchOperations}.
+	 *
+	 * @param elasticsearchOperations must not be {@literal null}.
+	 */
+	public ReactiveElasticsearchRepositoryFactory(ReactiveElasticsearchOperations elasticsearchOperations) {
+
+		Assert.notNull(elasticsearchOperations, "ReactiveElasticsearchOperations must not be null!");
+
+		this.operations = elasticsearchOperations;
+		this.mappingContext = elasticsearchOperations.getElasticsearchConverter().getMappingContext();
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.core.support.RepositoryFactorySupport#getRepositoryBaseClass(org.springframework.data.repository.core.RepositoryMetadata)
+	 */
+	@Override
+	protected Class<?> getRepositoryBaseClass(RepositoryMetadata metadata) {
+		return SimpleReactiveElasticsearchRepository.class;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.core.support.RepositoryFactorySupport#getTargetRepository(org.springframework.data.repository.core.RepositoryInformation)
+	 */
+	@Override
+	protected Object getTargetRepository(RepositoryInformation information) {
+
+		ElasticsearchEntityInformation<?, Serializable> entityInformation = getEntityInformation(
+				information.getDomainType(), information);
+		return getTargetRepositoryViaReflection(information, entityInformation, operations);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.core.support.RepositoryFactorySupport#getQueryLookupStrategy(org.springframework.data.repository.query.QueryLookupStrategy.Key, org.springframework.data.repository.query.EvaluationContextProvider)
+	 */
+	@Override
+	protected Optional<QueryLookupStrategy> getQueryLookupStrategy(@Nullable Key key,
+			QueryMethodEvaluationContextProvider evaluationContextProvider) {
+		return Optional.of(new ElasticsearchQueryLookupStrategy(operations, evaluationContextProvider, mappingContext));
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.core.support.RepositoryFactorySupport#getEntityInformation(java.lang.Class)
+	 */
+	public <T, ID> ElasticsearchEntityInformation<T, ID> getEntityInformation(Class<T> domainClass) {
+		return getEntityInformation(domainClass, null);
+	}
+
+	@SuppressWarnings("unchecked")
+	private <T, ID> ElasticsearchEntityInformation<T, ID> getEntityInformation(Class<T> domainClass,
+			@Nullable RepositoryInformation information) {
+
+		ElasticsearchPersistentEntity<?> entity = mappingContext.getRequiredPersistentEntity(domainClass);
+
+		return new MappingElasticsearchEntityInformation<>((ElasticsearchPersistentEntity<T>) entity, entity.getIndexName(),
+				entity.getIndexType());
+	}
+
+	/**
+	 * @author Christoph Strobl
+	 */
+	@RequiredArgsConstructor(access = AccessLevel.PACKAGE)
+	private static class ElasticsearchQueryLookupStrategy implements QueryLookupStrategy {
+
+		private final ReactiveElasticsearchOperations operations;
+		private final QueryMethodEvaluationContextProvider evaluationContextProvider;
+		private final MappingContext<? extends ElasticsearchPersistentEntity<?>, ElasticsearchPersistentProperty> mappingContext;
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.repository.query.QueryLookupStrategy#resolveQuery(java.lang.reflect.Method, org.springframework.data.repository.core.RepositoryMetadata, org.springframework.data.projection.ProjectionFactory, org.springframework.data.repository.core.NamedQueries)
+		 */
+		@Override
+		public RepositoryQuery resolveQuery(Method method, RepositoryMetadata metadata, ProjectionFactory factory,
+				NamedQueries namedQueries) {
+
+			ReactiveElasticsearchQueryMethod queryMethod = new ReactiveElasticsearchQueryMethod(method, metadata, factory,
+					mappingContext);
+			String namedQueryName = queryMethod.getNamedQueryName();
+
+			if (namedQueries.hasQuery(namedQueryName)) {
+				String namedQuery = namedQueries.getQuery(namedQueryName);
+
+				return new ReactiveElasticsearchStringQuery(namedQuery, queryMethod, operations, EXPRESSION_PARSER,
+						evaluationContextProvider);
+			} else if (queryMethod.hasAnnotatedQuery()) {
+				return new ReactiveElasticsearchStringQuery(queryMethod, operations, EXPRESSION_PARSER,
+						evaluationContextProvider);
+			} else {
+				return new ReactivePartTreeElasticsearchQuery(queryMethod, operations);
+			}
+		}
+	}
+}

src/main/java/org/springframework/data/elasticsearch/repository/support/ReactiveElasticsearchRepositoryFactoryBean.java

@@ -0,0 +1,109 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.support;
+
+import org.springframework.data.elasticsearch.core.ReactiveElasticsearchOperations;
+import org.springframework.data.mapping.context.MappingContext;
+import org.springframework.data.repository.Repository;
+import org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport;
+import org.springframework.data.repository.core.support.RepositoryFactorySupport;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+
+/**
+ * {@link org.springframework.beans.factory.FactoryBean} to create
+ * {@link org.springframework.data.elasticsearch.repository.ReactiveElasticsearchRepository} instances.
+ *
+ * @author Christoph Strobl
+ * @since 3.2
+ * @see org.springframework.data.repository.reactive.ReactiveSortingRepository
+ */
+public class ReactiveElasticsearchRepositoryFactoryBean<T extends Repository<S, ID>, S, ID>
+		extends RepositoryFactoryBeanSupport<T, S, ID> {
+
+	private @Nullable ReactiveElasticsearchOperations operations;
+	private boolean mappingContextConfigured = false;
+
+	/**
+	 * Creates a new {@link ReactiveElasticsearchRepositoryFactoryBean} for the given repository interface.
+	 *
+	 * @param repositoryInterface must not be {@literal null}.
+	 */
+	public ReactiveElasticsearchRepositoryFactoryBean(Class<? extends T> repositoryInterface) {
+		super(repositoryInterface);
+	}
+
+	/**
+	 * Configures the {@link ReactiveElasticsearchOperations} to be used.
+	 *
+	 * @param operations the operations to set
+	 */
+	public void setReactiveElasticsearchOperations(@Nullable ReactiveElasticsearchOperations operations) {
+		this.operations = operations;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport#setMappingContext(org.springframework.data.mapping.context.MappingContext)
+	 */
+	@Override
+	protected void setMappingContext(MappingContext<?, ?> mappingContext) {
+
+		super.setMappingContext(mappingContext);
+		this.mappingContextConfigured = true;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 *
+	 * @see
+	 * org.springframework.data.repository.support.RepositoryFactoryBeanSupport
+	 * #createRepositoryFactory()
+	 */
+	@Override
+	protected final RepositoryFactorySupport createRepositoryFactory() {
+
+		return getFactoryInstance(operations);
+	}
+
+	/**
+	 * Creates and initializes a {@link RepositoryFactorySupport} instance.
+	 *
+	 * @param operations
+	 * @return
+	 */
+	protected RepositoryFactorySupport getFactoryInstance(ReactiveElasticsearchOperations operations) {
+		return new ReactiveElasticsearchRepositoryFactory(operations);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 *
+	 * @see
+	 * org.springframework.data.repository.support.RepositoryFactoryBeanSupport
+	 * #afterPropertiesSet()
+	 */
+	@Override
+	public void afterPropertiesSet() {
+
+		super.afterPropertiesSet();
+		Assert.state(operations != null, "ReactiveElasticsearchOperations must not be null!");
+
+		if (!mappingContextConfigured) {
+			setMappingContext(operations.getElasticsearchConverter().getMappingContext());
+		}
+	}
+}

src/main/java/org/springframework/data/elasticsearch/repository/support/SimpleReactiveElasticsearchRepository.java

@@ -0,0 +1,185 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.support;
+
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+import org.reactivestreams.Publisher;
+import org.springframework.data.domain.Sort;
+import org.springframework.data.elasticsearch.core.ReactiveElasticsearchOperations;
+import org.springframework.data.elasticsearch.core.query.Query;
+import org.springframework.data.elasticsearch.repository.ReactiveElasticsearchRepository;
+import org.springframework.util.Assert;
+
+/**
+ * @author Christoph Strobl
+ * @since 3.2
+ */
+public class SimpleReactiveElasticsearchRepository<T, ID> implements ReactiveElasticsearchRepository<T, ID> {
+
+	private final ElasticsearchEntityInformation<T, ID> entityInformation;
+	private final ReactiveElasticsearchOperations elasticsearchOperations;
+
+	public SimpleReactiveElasticsearchRepository(ElasticsearchEntityInformation<T, ID> entityInformation,
+			ReactiveElasticsearchOperations elasticsearchOperations) {
+
+		Assert.notNull(entityInformation, "EntityInformation must not be null!");
+		Assert.notNull(elasticsearchOperations, "ElasticsearchOperations must not be null!");
+
+		this.entityInformation = entityInformation;
+		this.elasticsearchOperations = elasticsearchOperations;
+	}
+
+	@Override
+	public Flux<T> findAll(Sort sort) {
+
+		return elasticsearchOperations.find(Query.findAll().addSort(sort), entityInformation.getJavaType(),
+				entityInformation.getIndexName(), entityInformation.getType());
+	}
+
+	@Override
+	public <S extends T> Mono<S> save(S entity) {
+
+		Assert.notNull(entity, "Entity must not be null!");
+		return elasticsearchOperations.save(entity, entityInformation.getIndexName(), entityInformation.getType());
+	}
+
+	@Override
+	public <S extends T> Flux<S> saveAll(Iterable<S> entities) {
+
+		Assert.notNull(entities, "Entities must not be null!");
+		return saveAll(Flux.fromIterable(entities));
+	}
+
+	@Override
+	public <S extends T> Flux<S> saveAll(Publisher<S> entityStream) {
+
+		Assert.notNull(entityStream, "EntityStream must not be null!");
+		return Flux.from(entityStream).flatMap(this::save);
+	}
+
+	@Override
+	public Mono<T> findById(ID id) {
+
+		Assert.notNull(id, "Id must not be null!");
+		return elasticsearchOperations.findById(convertId(id), entityInformation.getJavaType(),
+				entityInformation.getIndexName(), entityInformation.getType());
+	}
+
+	@Override
+	public Mono<T> findById(Publisher<ID> id) {
+
+		Assert.notNull(id, "Id must not be null!");
+		return Mono.from(id).flatMap(this::findById);
+	}
+
+	@Override
+	public Mono<Boolean> existsById(ID id) {
+
+		Assert.notNull(id, "Id must not be null!");
+		return elasticsearchOperations.exists(convertId(id), entityInformation.getJavaType(),
+				entityInformation.getIndexName(), entityInformation.getType());
+	}
+
+	@Override
+	public Mono<Boolean> existsById(Publisher<ID> id) {
+
+		Assert.notNull(id, "Id must not be null!");
+		return Mono.from(id).flatMap(this::existsById);
+	}
+
+	@Override
+	public Flux<T> findAll() {
+
+		return elasticsearchOperations.find(Query.findAll(), entityInformation.getJavaType(),
+				entityInformation.getIndexName(), entityInformation.getType());
+	}
+
+	@Override
+	public Flux<T> findAllById(Iterable<ID> ids) {
+
+		Assert.notNull(ids, "Ids must not be null!");
+
+		return Flux.fromIterable(ids).flatMap(this::findById);
+	}
+
+	@Override
+	public Flux<T> findAllById(Publisher<ID> idStream) {
+
+		Assert.notNull(idStream, "IdStream must not be null!");
+		return Flux.from(idStream).buffer().flatMap(this::findAllById);
+	}
+
+	@Override
+	public Mono<Long> count() {
+
+		return elasticsearchOperations.count(Query.findAll(), entityInformation.getJavaType(),
+				entityInformation.getIndexName(), entityInformation.getType());
+	}
+
+	@Override
+	public Mono<Void> deleteById(ID id) {
+
+		Assert.notNull(id, "Id must not be null!");
+		return elasticsearchOperations
+				.deleteById(convertId(id), entityInformation.getJavaType(), entityInformation.getIndexName(),
+						entityInformation.getType()) //
+				.then();
+	}
+
+	@Override
+	public Mono<Void> deleteById(Publisher<ID> id) {
+
+		Assert.notNull(id, "Id must not be null!");
+		return Mono.from(id).flatMap(this::deleteById);
+	}
+
+	@Override
+	public Mono<Void> delete(T entity) {
+
+		Assert.notNull(entity, "Entity must not be null!");
+		return elasticsearchOperations.delete(entity, entityInformation.getIndexName(), entityInformation.getType()) //
+				.then();
+	}
+
+	@Override
+	public Mono<Void> deleteAll(Iterable<? extends T> entities) {
+
+		Assert.notNull(entities, "Entities must not be null!");
+		return deleteAll(Flux.fromIterable(entities));
+	}
+
+	@Override
+	public Mono<Void> deleteAll(Publisher<? extends T> entityStream) {
+
+		Assert.notNull(entityStream, "EntityStream must not be null!");
+		return Flux.from(entityStream).flatMap(this::delete).then();
+	}
+
+	@Override
+	public Mono<Void> deleteAll() {
+
+		return elasticsearchOperations
+				.deleteBy(Query.findAll(), entityInformation.getJavaType(), entityInformation.getIndexName(),
+						entityInformation.getType()) //
+				.then();
+	}
+
+	private String convertId(Object id) {
+		return elasticsearchOperations.getElasticsearchConverter().convertId(id);
+	}
+}

src/test/java/org/springframework/data/elasticsearch/TestUtils.java

@@ -17,14 +17,16 @@ package org.springframework.data.elasticsearch;
 
 import lombok.SneakyThrows;
 
-import java.io.IOException;
 import java.time.Duration;
 
 import org.elasticsearch.ElasticsearchStatusException;
 import org.elasticsearch.action.admin.indices.delete.DeleteIndexRequest;
 import org.elasticsearch.action.get.GetRequest;
+import org.elasticsearch.action.search.SearchRequest;
 import org.elasticsearch.client.RequestOptions;
 import org.elasticsearch.client.RestHighLevelClient;
+import org.elasticsearch.index.query.QueryBuilders;
+import org.elasticsearch.search.builder.SearchSourceBuilder;
 import org.springframework.data.elasticsearch.client.ClientConfiguration;
 import org.springframework.data.elasticsearch.client.RestClients;
 import org.springframework.data.elasticsearch.client.reactive.ReactiveElasticsearchClient;
@@ -84,6 +86,18 @@ public final class TestUtils {
 		}
 	}
 
+	@SneakyThrows
+	public static boolean isEmptyIndex(String indexName) {
+
+		try (RestHighLevelClient client = restHighLevelClient()) {
+
+			return 0L == client
+					.search(new SearchRequest(indexName)
+							.source(SearchSourceBuilder.searchSource().query(QueryBuilders.matchAllQuery())), RequestOptions.DEFAULT)
+					.getHits().getTotalHits();
+		}
+	}
+
 	public static OfType documentWithId(String id) {
 		return new DocumentLookup(id);
 	}
@@ -106,19 +120,16 @@ public final class TestUtils {
 		}
 
 		@Override
+		@SneakyThrows
 		public boolean existsIn(String index) {
 
 			GetRequest request = new GetRequest(index).id(id);
 			if (StringUtils.hasText(type)) {
 				request = request.type(type);
 			}
-			try {
-				return restHighLevelClient().get(request, RequestOptions.DEFAULT).isExists();
-			} catch (IOException e) {
-				e.printStackTrace();
+			try (RestHighLevelClient client = restHighLevelClient()) {
+				return client.get(request, RequestOptions.DEFAULT).isExists();
 			}
-
-			return false;
 		}
 
 		@Override

src/test/java/org/springframework/data/elasticsearch/client/reactive/ReactiveElasticsearchClientTests.java

@@ -17,6 +17,7 @@ package org.springframework.data.elasticsearch.client.reactive;
 
 import static org.assertj.core.api.Assertions.*;
 
+import org.springframework.data.elasticsearch.ElasticsearchException;
 import reactor.test.StepVerifier;
 
 import java.io.IOException;
@@ -135,6 +136,16 @@ public class ReactiveElasticsearchClientTests {
 				.verifyComplete();
 	}
 
+	@Test // DATAES-519
+	public void getOnNonExistingIndexShouldThrowException() {
+
+		client.get(new GetRequest(INDEX_I, TYPE_I, "nonono"))
+				.as(StepVerifier::create)
+				.expectError(ElasticsearchStatusException.class)
+				.verify();
+	}
+
+
 	@Test // DATAES-488
 	public void getShouldFetchDocumentById() {
 

src/test/java/org/springframework/data/elasticsearch/core/ReactiveElasticsearchTemplateTests.java

@@ -177,6 +177,14 @@ public class ReactiveElasticsearchTemplateTests {
 		template.save(null);
 	}
 
+	@Test // DATAES-519
+	public void findByIdShouldCompleteWhenIndexDoesNotExist() {
+
+		template.findById("foo", SampleEntity.class, "no-such-index") //
+				.as(StepVerifier::create) //
+				.verifyComplete();
+	}
+
 	@Test // DATAES-504
 	public void findByIdShouldReturnEntity() {
 
@@ -245,6 +253,15 @@ public class ReactiveElasticsearchTemplateTests {
 				.verifyComplete();
 	}
 
+	@Test // DATAES-519
+	public void existsShouldReturnFalseWhenIndexDoesNotExist() {
+
+		template.exists("foo", SampleEntity.class, "no-such-index") //
+				.as(StepVerifier::create) //
+				.expectNext(false) //
+				.verifyComplete();
+	}
+
 	@Test // DATAES-504
 	public void existsShouldReturnTrueWhenFound() {
 
@@ -269,6 +286,14 @@ public class ReactiveElasticsearchTemplateTests {
 				.verifyComplete();
 	}
 
+	@Test // DATAES-519
+	public void findShouldCompleteWhenIndexDoesNotExist() {
+
+		template.find(new CriteriaQuery(Criteria.where("message").is("some message")), SampleEntity.class, "no-such-index") //
+				.as(StepVerifier::create) //
+				.verifyComplete();
+	}
+
 	@Test // DATAES-504
 	public void findShouldApplyCriteria() {
 
@@ -392,6 +417,15 @@ public class ReactiveElasticsearchTemplateTests {
 				.verifyComplete();
 	}
 
+	@Test // DATAES-519
+	public void countShouldReturnZeroWhenIndexDoesNotExist() {
+
+		template.count(SampleEntity.class) //
+				.as(StepVerifier::create) //
+				.expectNext(0L) //
+				.verifyComplete();
+	}
+
 	@Test // DATAES-504
 	public void countShouldReturnCountAllWhenGivenNoQuery() {
 
@@ -416,6 +450,14 @@ public class ReactiveElasticsearchTemplateTests {
 				.verifyComplete();
 	}
 
+	@Test // DATAES-519
+	public void deleteByIdShouldCompleteWhenIndexDoesNotExist() {
+
+		template.deleteById("does-not-exists", SampleEntity.class, "no-such-index") //
+				.as(StepVerifier::create)//
+				.verifyComplete();
+	}
+
 	@Test // DATAES-504
 	public void deleteByIdShouldRemoveExistingDocumentById() {
 
@@ -462,6 +504,18 @@ public class ReactiveElasticsearchTemplateTests {
 				.verifyComplete();
 	}
 
+	@Test // DATAES-519
+	@ElasticsearchVersion(asOf = "6.5.0")
+	public void deleteByQueryShouldReturnZeroWhenIndexDoesNotExist() {
+
+		CriteriaQuery query = new CriteriaQuery(new Criteria("message").contains("test"));
+
+		template.deleteBy(query, SampleEntity.class) //
+				.as(StepVerifier::create) //
+				.expectNext(0L) //
+				.verifyComplete();
+	}
+
 	@Test // DATAES-504
 	@ElasticsearchVersion(asOf = "6.5.0")
 	public void deleteByQueryShouldReturnNumberOfDeletedDocuments() {

src/test/java/org/springframework/data/elasticsearch/repository/config/ReactiveElasticsearchRepositoriesRegistrarTests.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.config;
+
+import org.assertj.core.api.Assertions;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.elasticsearch.TestUtils;
+import org.springframework.data.elasticsearch.core.ReactiveElasticsearchTemplate;
+import org.springframework.data.elasticsearch.entities.SampleEntity;
+import org.springframework.data.elasticsearch.repository.ReactiveElasticsearchRepository;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+/**
+ * @author Christoph Strobl
+ * @currentRead Fool's Fate - Robin Hobb
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration
+public class ReactiveElasticsearchRepositoriesRegistrarTests {
+
+	@Configuration
+	@EnableReactiveElasticsearchRepositories(considerNestedRepositories = true)
+	static class Config {
+
+		@Bean
+		public ReactiveElasticsearchTemplate reactiveElasticsearchTemplate() {
+			return new ReactiveElasticsearchTemplate(TestUtils.reactiveClient());
+		}
+	}
+
+	@Autowired ReactiveSampleEntityRepository repository;
+	@Autowired ApplicationContext context;
+
+	@Test // DATAES-519
+	public void testConfiguration() {
+
+		Assertions.assertThat(context).isNotNull();
+		Assertions.assertThat(repository).isNotNull();
+
+	}
+
+	interface ReactiveSampleEntityRepository extends ReactiveElasticsearchRepository<SampleEntity, String> {}
+
+}

src/test/java/org/springframework/data/elasticsearch/repository/config/ReactiveElasticsearchRepositoryConfigurationExtensionUnitTests.java

@@ -0,0 +1,113 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.config;
+
+import static org.junit.Assert.*;
+
+import java.util.Collection;
+
+import org.junit.Test;
+import org.springframework.beans.factory.support.BeanDefinitionRegistry;
+import org.springframework.beans.factory.support.DefaultListableBeanFactory;
+import org.springframework.core.env.Environment;
+import org.springframework.core.env.StandardEnvironment;
+import org.springframework.core.io.ResourceLoader;
+import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
+import org.springframework.core.type.StandardAnnotationMetadata;
+import org.springframework.data.elasticsearch.annotations.Document;
+import org.springframework.data.elasticsearch.repository.ReactiveElasticsearchRepository;
+import org.springframework.data.repository.config.AnnotationRepositoryConfigurationSource;
+import org.springframework.data.repository.config.RepositoryConfiguration;
+import org.springframework.data.repository.config.RepositoryConfigurationSource;
+import org.springframework.data.repository.reactive.ReactiveCrudRepository;
+
+/**
+ * @author Christoph Strobl
+ * @currentRead Fool's Fate - Robin Hobb
+ */
+public class ReactiveElasticsearchRepositoryConfigurationExtensionUnitTests {
+
+	StandardAnnotationMetadata metadata = new StandardAnnotationMetadata(Config.class, true);
+	ResourceLoader loader = new PathMatchingResourcePatternResolver();
+	Environment environment = new StandardEnvironment();
+	BeanDefinitionRegistry registry = new DefaultListableBeanFactory();
+
+	RepositoryConfigurationSource configurationSource = new AnnotationRepositoryConfigurationSource(metadata,
+			EnableReactiveElasticsearchRepositories.class, loader, environment, registry);
+
+	@Test // DATAES-519
+	public void isStrictMatchIfDomainTypeIsAnnotatedWithDocument() {
+
+		ReactiveElasticsearchRepositoryConfigurationExtension extension = new ReactiveElasticsearchRepositoryConfigurationExtension();
+		assertHasRepo(CrudRepositoryForAnnotatedType.class,
+				extension.getRepositoryConfigurations(configurationSource, loader, true));
+	}
+
+	@Test // DATAES-519
+	public void isStrictMatchIfRepositoryExtendsStoreSpecificBase() {
+
+		ReactiveElasticsearchRepositoryConfigurationExtension extension = new ReactiveElasticsearchRepositoryConfigurationExtension();
+		assertHasRepo(EsRepositoryForUnAnnotatedType.class,
+				extension.getRepositoryConfigurations(configurationSource, loader, true));
+	}
+
+	@Test // DATAES-519
+	public void isNotStrictMatchIfDomainTypeIsNotAnnotatedWithDocument() {
+
+		ReactiveElasticsearchRepositoryConfigurationExtension extension = new ReactiveElasticsearchRepositoryConfigurationExtension();
+		assertDoesNotHaveRepo(CrudRepositoryForUnAnnotatedType.class,
+				extension.getRepositoryConfigurations(configurationSource, loader, true));
+	}
+
+	private static void assertHasRepo(Class<?> repositoryInterface,
+			Collection<RepositoryConfiguration<RepositoryConfigurationSource>> configs) {
+
+		for (RepositoryConfiguration<?> config : configs) {
+			if (config.getRepositoryInterface().equals(repositoryInterface.getName())) {
+				return;
+			}
+		}
+
+		fail("Expected to find config for repository interface ".concat(repositoryInterface.getName()).concat(" but got ")
+				.concat(configs.toString()));
+	}
+
+	private static void assertDoesNotHaveRepo(Class<?> repositoryInterface,
+			Collection<RepositoryConfiguration<RepositoryConfigurationSource>> configs) {
+
+		for (RepositoryConfiguration<?> config : configs) {
+			if (config.getRepositoryInterface().equals(repositoryInterface.getName())) {
+				fail("Expected not to find config for repository interface ".concat(repositoryInterface.getName()));
+			}
+		}
+	}
+
+	@EnableReactiveElasticsearchRepositories(considerNestedRepositories = true)
+	static class Config {
+
+	}
+
+	@Document(indexName = "star-wars", type = "character")
+	static class SwCharacter {}
+
+	static class Store {}
+
+	interface CrudRepositoryForAnnotatedType extends ReactiveCrudRepository<SwCharacter, String> {}
+
+	interface CrudRepositoryForUnAnnotatedType extends ReactiveCrudRepository<Store, String> {}
+
+	interface EsRepositoryForUnAnnotatedType extends ReactiveElasticsearchRepository<Store, String> {}
+}

src/test/java/org/springframework/data/elasticsearch/repository/query/ReactiveElasticsearchQueryMethodUnitTests.java

@@ -0,0 +1,129 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.query;
+
+import static org.assertj.core.api.Assertions.*;
+
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+import java.lang.reflect.Method;
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.dao.InvalidDataAccessApiUsageException;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.domain.Slice;
+import org.springframework.data.elasticsearch.core.mapping.SimpleElasticsearchMappingContext;
+import org.springframework.data.elasticsearch.entities.Person;
+import org.springframework.data.projection.ProjectionFactory;
+import org.springframework.data.projection.SpelAwareProxyProjectionFactory;
+import org.springframework.data.repository.Repository;
+import org.springframework.data.repository.core.support.DefaultRepositoryMetadata;
+
+/**
+ * @author Christoph Strobl
+ * @currentRead Fool's Fate - Robin Hobb
+ */
+public class ReactiveElasticsearchQueryMethodUnitTests {
+
+	SimpleElasticsearchMappingContext mappingContext;
+
+	@Before
+	public void setUp() {
+		mappingContext = new SimpleElasticsearchMappingContext();
+	}
+
+	@Test // DATAES-519
+	public void detectsCollectionFromRepoTypeIfReturnTypeNotAssignable() throws Exception {
+
+		ReactiveElasticsearchQueryMethod queryMethod = queryMethod(NonReactiveRepository.class, "method");
+		ElasticsearchEntityMetadata<?> metadata = queryMethod.getEntityInformation();
+
+		assertThat(metadata.getJavaType()).isAssignableFrom(Person.class);
+		assertThat(metadata.getIndexName()).isEqualTo("test-index-person");
+		assertThat(metadata.getIndexTypeName()).isEqualTo("user");
+	}
+
+	@Test(expected = IllegalArgumentException.class) // DATAES-519
+	public void rejectsNullMappingContext() throws Exception {
+
+		Method method = PersonRepository.class.getMethod("findByName", String.class);
+
+		new ReactiveElasticsearchQueryMethod(method, new DefaultRepositoryMetadata(PersonRepository.class),
+				new SpelAwareProxyProjectionFactory(), null);
+	}
+
+	@Test(expected = IllegalStateException.class) // DATAES-519
+	public void rejectsMonoPageableResult() throws Exception {
+		queryMethod(PersonRepository.class, "findMonoByName", String.class, Pageable.class);
+	}
+
+	@Test(expected = InvalidDataAccessApiUsageException.class) // DATAES-519
+	public void throwsExceptionOnWrappedPage() throws Exception {
+		queryMethod(PersonRepository.class, "findMonoPageByName", String.class, Pageable.class);
+	}
+
+	@Test(expected = InvalidDataAccessApiUsageException.class) // DATAES-519
+	public void throwsExceptionOnWrappedSlice() throws Exception {
+		queryMethod(PersonRepository.class, "findMonoSliceByName", String.class, Pageable.class);
+	}
+
+	@Test // DATAES-519
+	public void allowsPageableOnFlux() throws Exception {
+		queryMethod(PersonRepository.class, "findByName", String.class, Pageable.class);
+	}
+
+	@Test // DATAES-519
+	public void fallsBackToRepositoryDomainTypeIfMethodDoesNotReturnADomainType() throws Exception {
+
+		ReactiveElasticsearchQueryMethod method = queryMethod(PersonRepository.class, "deleteByName", String.class);
+
+		assertThat(method.getEntityInformation().getJavaType()).isAssignableFrom(Person.class);
+	}
+
+	private ReactiveElasticsearchQueryMethod queryMethod(Class<?> repository, String name, Class<?>... parameters)
+			throws Exception {
+
+		Method method = repository.getMethod(name, parameters);
+		ProjectionFactory factory = new SpelAwareProxyProjectionFactory();
+		return new ReactiveElasticsearchQueryMethod(method, new DefaultRepositoryMetadata(repository), factory,
+				mappingContext);
+	}
+
+	interface PersonRepository extends Repository<Person, String> {
+
+		Mono<Person> findMonoByName(String name, Pageable pageRequest);
+
+		Mono<Page<Person>> findMonoPageByName(String name, Pageable pageRequest);
+
+		Mono<Slice<Person>> findMonoSliceByName(String name, Pageable pageRequest);
+
+		Flux<Person> findByName(String name);
+
+		Flux<Person> findByName(String name, Pageable pageRequest);
+
+		void deleteByName(String name);
+	}
+
+	interface NonReactiveRepository extends Repository<Person, Long> {
+
+		List<Person> method();
+	}
+
+}

src/test/java/org/springframework/data/elasticsearch/repository/query/ReactiveElasticsearchStringQueryUnitTests.java

@@ -0,0 +1,108 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.query;
+
+import static org.assertj.core.api.Assertions.*;
+
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+import java.lang.reflect.Method;
+
+import org.junit.Before;
+import org.junit.Ignore;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+import org.springframework.data.elasticsearch.annotations.Query;
+import org.springframework.data.elasticsearch.core.ReactiveElasticsearchOperations;
+import org.springframework.data.elasticsearch.core.convert.ElasticsearchConverter;
+import org.springframework.data.elasticsearch.core.convert.MappingElasticsearchConverter;
+import org.springframework.data.elasticsearch.core.mapping.SimpleElasticsearchMappingContext;
+import org.springframework.data.elasticsearch.core.query.StringQuery;
+import org.springframework.data.elasticsearch.entities.Person;
+import org.springframework.data.projection.ProjectionFactory;
+import org.springframework.data.projection.SpelAwareProxyProjectionFactory;
+import org.springframework.data.repository.Repository;
+import org.springframework.data.repository.core.support.DefaultRepositoryMetadata;
+import org.springframework.data.repository.query.QueryMethodEvaluationContextProvider;
+import org.springframework.expression.spel.standard.SpelExpressionParser;
+
+/**
+ * @author Christoph Strobl
+ * @currentRead Fool's Fate - Robin Hobb
+ */
+@RunWith(MockitoJUnitRunner.class)
+public class ReactiveElasticsearchStringQueryUnitTests {
+
+	SpelExpressionParser PARSER = new SpelExpressionParser();
+	ElasticsearchConverter converter;
+
+	@Mock ReactiveElasticsearchOperations operations;
+
+	@Before
+	public void setUp() {
+		converter = new MappingElasticsearchConverter(new SimpleElasticsearchMappingContext());
+	}
+
+	@Test // DATAES-519
+	public void bindsSimplePropertyCorrectly() throws Exception {
+
+		ReactiveElasticsearchStringQuery elasticsearchStringQuery = createQueryForMethod("findByName", String.class);
+		StubParameterAccessor accesor = new StubParameterAccessor("Luke");
+
+		org.springframework.data.elasticsearch.core.query.Query query = elasticsearchStringQuery.createQuery(accesor);
+		StringQuery reference = new StringQuery("{ 'bool' : { 'must' : { 'term' : { 'name' : 'Luke' } } } }");
+
+		assertThat(query).isInstanceOf(StringQuery.class);
+		assertThat(((StringQuery) query).getSource()).isEqualTo(reference.getSource());
+	}
+
+	@Test // DATAES-519
+	@Ignore("TODO: fix spel query integration")
+	public void bindsExpressionPropertyCorrectly() throws Exception {
+
+		ReactiveElasticsearchStringQuery elasticsearchStringQuery = createQueryForMethod("findByNameWithExpression",
+				String.class);
+		StubParameterAccessor accesor = new StubParameterAccessor("Luke");
+
+		org.springframework.data.elasticsearch.core.query.Query query = elasticsearchStringQuery.createQuery(accesor);
+		StringQuery reference = new StringQuery("{ 'bool' : { 'must' : { 'term' : { 'name' : 'Luke' } } } }");
+
+		assertThat(query).isInstanceOf(StringQuery.class);
+		assertThat(((StringQuery) query).getSource()).isEqualTo(reference.getSource());
+	}
+
+	private ReactiveElasticsearchStringQuery createQueryForMethod(String name, Class<?>... parameters) throws Exception {
+
+		Method method = SampleRepository.class.getMethod(name, parameters);
+		ProjectionFactory factory = new SpelAwareProxyProjectionFactory();
+		ReactiveElasticsearchQueryMethod queryMethod = new ReactiveElasticsearchQueryMethod(method,
+				new DefaultRepositoryMetadata(SampleRepository.class), factory, converter.getMappingContext());
+		return new ReactiveElasticsearchStringQuery(queryMethod, operations, PARSER,
+				QueryMethodEvaluationContextProvider.DEFAULT);
+	}
+
+	private interface SampleRepository extends Repository<Person, String> {
+
+		@Query("{ 'bool' : { 'must' : { 'term' : { 'name' : '?0' } } } }")
+		Mono<Person> findByName(String name);
+
+		@Query("{ 'bool' : { 'must' : { 'term' : { 'name' : '?#{[0]}' } } } }")
+		Flux<Person> findByNameWithExpression(String param0);
+	}
+}

src/test/java/org/springframework/data/elasticsearch/repository/query/StubParameterAccessor.java

@@ -0,0 +1,98 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.query;
+
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.Optional;
+
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.domain.Sort;
+import org.springframework.data.repository.query.ParameterAccessor;
+
+/**
+ * Simple {@link ParameterAccessor} that returns the given parameters unfiltered.
+ *
+ * @author Christoph Strobl
+ * @currentRead Fool's Fate - Robin Hobb
+ */
+class StubParameterAccessor implements ElasticsearchParameterAccessor {
+
+	private final Object[] values;
+
+	@SuppressWarnings("unchecked")
+	public StubParameterAccessor(Object... values) {
+		this.values = values;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.query.ParameterAccessor#getPageable()
+	 */
+	public Pageable getPageable() {
+		return null;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.query.ParameterAccessor#getBindableValue(int)
+	 */
+	public Object getBindableValue(int index) {
+		return values[index];
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.query.ParameterAccessor#hasBindableNullValue()
+	 */
+	public boolean hasBindableNullValue() {
+		return false;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.query.ParameterAccessor#getSort()
+	 */
+	public Sort getSort() {
+		return Sort.unsorted();
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.query.ParameterAccessor#iterator()
+	 */
+	public Iterator<Object> iterator() {
+		return Arrays.asList(values).iterator();
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.elasticsearch.repository.query.ElasticsearchParameterAccessor#getValues()
+	 */
+	@Override
+	public Object[] getValues() {
+		return this.values;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.repository.query.ParameterAccessor#getDynamicProjection()
+	 */
+	@Override
+	public Optional<Class<?>> getDynamicProjection() {
+		return Optional.empty();
+	}
+}

src/test/java/org/springframework/data/elasticsearch/repository/support/SimpleReactiveElasticsearchRepositoryTests.java

@@ -0,0 +1,492 @@
+/*
+ * Copyright 2019 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
+ *
+ *      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.springframework.data.elasticsearch.repository.support;
+
+import static org.assertj.core.api.Assertions.*;
+
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+import reactor.test.StepVerifier;
+
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.UUID;
+
+import org.elasticsearch.action.bulk.BulkRequest;
+import org.elasticsearch.action.index.IndexRequest;
+import org.elasticsearch.action.support.WriteRequest.RefreshPolicy;
+import org.elasticsearch.client.RequestOptions;
+import org.elasticsearch.client.RestHighLevelClient;
+import org.junit.After;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.reactivestreams.Publisher;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.domain.Sort;
+import org.springframework.data.domain.Sort.Order;
+import org.springframework.data.elasticsearch.TestUtils;
+import org.springframework.data.elasticsearch.annotations.Query;
+import org.springframework.data.elasticsearch.client.reactive.ReactiveElasticsearchClient;
+import org.springframework.data.elasticsearch.config.AbstractReactiveElasticsearchConfiguration;
+import org.springframework.data.elasticsearch.entities.SampleEntity;
+import org.springframework.data.elasticsearch.repository.config.EnableReactiveElasticsearchRepositories;
+import org.springframework.data.repository.reactive.ReactiveCrudRepository;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.util.StringUtils;
+
+/**
+ * @author Christoph Strobl
+ * @currentRead Fool's Fate - Robin Hobb
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration
+public class SimpleReactiveElasticsearchRepositoryTests {
+
+	@Configuration
+	@EnableReactiveElasticsearchRepositories(considerNestedRepositories = true)
+	static class Config extends AbstractReactiveElasticsearchConfiguration {
+
+		@Override
+		public ReactiveElasticsearchClient reactiveElasticsearchClient() {
+			return TestUtils.reactiveClient();
+		}
+	}
+
+	static final String INDEX = "test-index-sample";
+	static final String TYPE = "test-type";
+
+	@Autowired ReactiveSampleEntityRepository repository;
+
+	@After
+	public void tearDown() {
+		TestUtils.deleteIndex(INDEX);
+	}
+
+	@Test // DATAES-519
+	public void saveShouldSaveSingleEntity() {
+
+		repository.save(SampleEntity.builder().build()) //
+				.as(StepVerifier::create) //
+				.consumeNextWith(it -> {
+					assertThat(TestUtils.documentWithId(it.getId()).ofType(TYPE).existsIn(INDEX)).isTrue();
+				}) //
+				.verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void saveShouldComputeMultipleEntities() {
+
+		repository
+				.saveAll(Arrays.asList(SampleEntity.builder().build(), SampleEntity.builder().build(),
+						SampleEntity.builder().build())) //
+				.as(StepVerifier::create) //
+				.consumeNextWith(it -> {
+					assertThat(TestUtils.documentWithId(it.getId()).ofType(TYPE).existsIn(INDEX)).isTrue();
+				}) //
+				.consumeNextWith(it -> {
+					assertThat(TestUtils.documentWithId(it.getId()).ofType(TYPE).existsIn(INDEX)).isTrue();
+				}) //
+				.consumeNextWith(it -> {
+					assertThat(TestUtils.documentWithId(it.getId()).ofType(TYPE).existsIn(INDEX)).isTrue();
+				}) //
+				.verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void findByIdShouldCompleteIfIndexDoesNotExist() {
+		repository.findById("id-two").as(StepVerifier::create).verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void findShouldRetrieveSingleEntityById() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").build(), //
+				SampleEntity.builder().id("id-two").build(), //
+				SampleEntity.builder().id("id-three").build());
+
+		repository.findById("id-two").as(StepVerifier::create)//
+				.consumeNextWith(it -> {
+					assertThat(it.getId()).isEqualTo("id-two");
+				}) //
+				.verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void findByIdShouldCompleteIfNothingFound() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").build(), //
+				SampleEntity.builder().id("id-two").build(), //
+				SampleEntity.builder().id("id-three").build());
+
+		repository.findById("does-not-exist").as(StepVerifier::create) //
+				.verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void findAllByIdByIdShouldCompleteIfIndexDoesNotExist() {
+		repository.findAllById(Arrays.asList("id-two", "id-two")).as(StepVerifier::create).verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void findAllByIdShouldRetrieveMatchingDocuments() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").build(), //
+				SampleEntity.builder().id("id-two").build(), //
+				SampleEntity.builder().id("id-three").build());
+
+		repository.findAllById(Arrays.asList("id-one", "id-two")) //
+				.as(StepVerifier::create)//
+				.expectNextCount(2) //
+				.verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void findAllByIdShouldCompleteWhenNothingFound() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").build(), //
+				SampleEntity.builder().id("id-two").build(), //
+				SampleEntity.builder().id("id-three").build());
+
+		repository.findAllById(Arrays.asList("can't", "touch", "this")) //
+				.as(StepVerifier::create)//
+				.verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void countShouldReturnZeroWhenIndexDoesNotExist() {
+		repository.count().as(StepVerifier::create).expectNext(0L).verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void countShouldCountDocuments() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").build(), //
+				SampleEntity.builder().id("id-two").build());
+
+		repository.count().as(StepVerifier::create).expectNext(2L).verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void existsByIdShouldReturnTrueIfExists() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").message("message").build(), //
+				SampleEntity.builder().id("id-two").message("test message").build(), //
+				SampleEntity.builder().id("id-three").message("test test").build());
+
+		repository.existsById("id-two") //
+				.as(StepVerifier::create) //
+				.expectNext(true) //
+				.verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void existsByIdShouldReturnFalseIfNotExists() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").message("message").build(), //
+				SampleEntity.builder().id("id-two").message("test message").build(), //
+				SampleEntity.builder().id("id-three").message("test test").build());
+
+		repository.existsById("wrecking ball") //
+				.as(StepVerifier::create) //
+				.expectNext(false) //
+				.verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void countShouldCountMatchingDocuments() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").message("message").build(), //
+				SampleEntity.builder().id("id-two").message("test message").build(), //
+				SampleEntity.builder().id("id-three").message("test test").build());
+
+		repository.countAllByMessage("test") //
+				.as(StepVerifier::create) //
+				.expectNext(2L) //
+				.verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void existsShouldReturnTrueIfExists() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").message("message").build(), //
+				SampleEntity.builder().id("id-two").message("test message").build(), //
+				SampleEntity.builder().id("id-three").message("test test").build());
+
+		repository.existsAllByMessage("message") //
+				.as(StepVerifier::create) //
+				.expectNext(true) //
+				.verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void existsShouldReturnFalseIfNotExists() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").message("message").build(), //
+				SampleEntity.builder().id("id-two").message("test message").build(), //
+				SampleEntity.builder().id("id-three").message("test test").build());
+
+		repository.existsAllByMessage("these days") //
+				.as(StepVerifier::create) //
+				.expectNext(false) //
+				.verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void deleteByIdShouldCompleteIfNothingDeleted() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").build(), //
+				SampleEntity.builder().id("id-two").build());
+
+		repository.deleteById("does-not-exist").as(StepVerifier::create).verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void deleteByIdShouldCompleteWhenIndexDoesNotExist() {
+		repository.deleteById("does-not-exist").as(StepVerifier::create).verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void deleteByIdShouldDeleteEntry() {
+
+		SampleEntity toBeDeleted = SampleEntity.builder().id("id-two").build();
+		bulkIndex(SampleEntity.builder().id("id-one").build(), toBeDeleted);
+
+		repository.deleteById(toBeDeleted.getId()).as(StepVerifier::create).verifyComplete();
+
+		assertThat(TestUtils.documentWithId(toBeDeleted.getId()).ofType(TYPE).existsIn(INDEX)).isFalse();
+	}
+
+	@Test // DATAES-519
+	public void deleteShouldDeleteEntry() {
+
+		SampleEntity toBeDeleted = SampleEntity.builder().id("id-two").build();
+		bulkIndex(SampleEntity.builder().id("id-one").build(), toBeDeleted);
+
+		repository.delete(toBeDeleted).as(StepVerifier::create).verifyComplete();
+
+		assertThat(TestUtils.documentWithId(toBeDeleted.getId()).ofType(TYPE).existsIn(INDEX)).isFalse();
+	}
+
+	@Test // DATAES-519
+	public void deleteAllShouldDeleteGivenEntries() {
+
+		SampleEntity toBeDeleted = SampleEntity.builder().id("id-one").build();
+		SampleEntity hangInThere = SampleEntity.builder().id("id-two").build();
+		SampleEntity toBeDeleted2 = SampleEntity.builder().id("id-three").build();
+
+		bulkIndex(toBeDeleted, hangInThere, toBeDeleted2);
+
+		repository.deleteAll(Arrays.asList(toBeDeleted, toBeDeleted2)).as(StepVerifier::create).verifyComplete();
+
+		assertThat(TestUtils.documentWithId(toBeDeleted.getId()).ofType(TYPE).existsIn(INDEX)).isFalse();
+		assertThat(TestUtils.documentWithId(toBeDeleted2.getId()).ofType(TYPE).existsIn(INDEX)).isFalse();
+		assertThat(TestUtils.documentWithId(hangInThere.getId()).ofType(TYPE).existsIn(INDEX)).isTrue();
+	}
+
+	@Test // DATAES-519
+	public void deleteAllShouldDeleteAllEntries() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").build(), //
+				SampleEntity.builder().id("id-two").build(), //
+				SampleEntity.builder().id("id-three").build());
+
+		repository.deleteAll().as(StepVerifier::create).verifyComplete();
+
+		assertThat(TestUtils.isEmptyIndex(INDEX)).isTrue();
+	}
+
+	@Test // DATAES-519
+	public void derivedFinderMethodShouldBeExecutedCorrectly() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").message("message").build(), //
+				SampleEntity.builder().id("id-two").message("test message").build(), //
+				SampleEntity.builder().id("id-three").message("test test").build());
+
+		repository.findAllByMessageLike("test") //
+				.as(StepVerifier::create) //
+				.expectNextCount(2) //
+				.verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void derivedFinderMethodShouldBeExecutedCorrectlyWhenGivenPublisher() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").message("message").build(), //
+				SampleEntity.builder().id("id-two").message("test message").build(), //
+				SampleEntity.builder().id("id-three").message("test test").build());
+
+		repository.findAllByMessage(Mono.just("test")) //
+				.as(StepVerifier::create) //
+				.expectNextCount(2) //
+				.verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void derivedFinderWithDerivedSortMethodShouldBeExecutedCorrectly() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").message("test").rate(3).build(), //
+				SampleEntity.builder().id("id-two").message("test test").rate(1).build(), //
+				SampleEntity.builder().id("id-three").message("test test").rate(2).build());
+
+		repository.findAllByMessageLikeOrderByRate("test") //
+				.as(StepVerifier::create) //
+				.consumeNextWith(it -> assertThat(it.getId()).isEqualTo("id-two")) //
+				.consumeNextWith(it -> assertThat(it.getId()).isEqualTo("id-three")) //
+				.consumeNextWith(it -> assertThat(it.getId()).isEqualTo("id-one")) //
+				.verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void derivedFinderMethodWithSortParameterShouldBeExecutedCorrectly() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").message("test").rate(3).build(), //
+				SampleEntity.builder().id("id-two").message("test test").rate(1).build(), //
+				SampleEntity.builder().id("id-three").message("test test").rate(2).build());
+
+		repository.findAllByMessage("test", Sort.by(Order.asc("rate"))) //
+				.as(StepVerifier::create) //
+				.consumeNextWith(it -> assertThat(it.getId()).isEqualTo("id-two")) //
+				.consumeNextWith(it -> assertThat(it.getId()).isEqualTo("id-three")) //
+				.consumeNextWith(it -> assertThat(it.getId()).isEqualTo("id-one")) //
+				.verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void derivedFinderMethodWithPageableParameterShouldBeExecutedCorrectly() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").message("test").rate(3).build(), //
+				SampleEntity.builder().id("id-two").message("test test").rate(1).build(), //
+				SampleEntity.builder().id("id-three").message("test test").rate(2).build());
+
+		repository.findAllByMessage("test", PageRequest.of(0, 2, Sort.by(Order.asc("rate")))) //
+				.as(StepVerifier::create) //
+				.consumeNextWith(it -> assertThat(it.getId()).isEqualTo("id-two")) //
+				.consumeNextWith(it -> assertThat(it.getId()).isEqualTo("id-three")) //
+				.verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void derivedFinderMethodReturningMonoShouldBeExecutedCorrectly() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").message("message").build(), //
+				SampleEntity.builder().id("id-two").message("test message").build(), //
+				SampleEntity.builder().id("id-three").message("test test").build());
+
+		repository.findFirstByMessageLike("test") //
+				.as(StepVerifier::create) //
+				.expectNextCount(1) //
+				.verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void annotatedFinderMethodShouldBeExecutedCorrectly() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").message("message").build(), //
+				SampleEntity.builder().id("id-two").message("test message").build(), //
+				SampleEntity.builder().id("id-three").message("test test").build());
+
+		repository.findAllViaAnnotatedQueryByMessageLike("test") //
+				.as(StepVerifier::create) //
+				.expectNextCount(2) //
+				.verifyComplete();
+	}
+
+	@Test // DATAES-519
+	public void derivedDeleteMethodShouldBeExecutedCorrectly() {
+
+		bulkIndex(SampleEntity.builder().id("id-one").message("message").build(), //
+				SampleEntity.builder().id("id-two").message("test message").build(), //
+				SampleEntity.builder().id("id-three").message("test test").build());
+
+		repository.deleteAllByMessage("message") //
+				.as(StepVerifier::create) //
+				.expectNext(2L) //
+				.verifyComplete();
+
+		assertThat(TestUtils.documentWithId("id-one").ofType(TYPE).existsIn(INDEX)).isFalse();
+		assertThat(TestUtils.documentWithId("id-two").ofType(TYPE).existsIn(INDEX)).isFalse();
+		assertThat(TestUtils.documentWithId("id-three").ofType(TYPE).existsIn(INDEX)).isTrue();
+	}
+
+	IndexRequest indexRequest(Map source, String index, String type) {
+
+		return new IndexRequest(index, type) //
+				.id(source.containsKey("id") ? source.get("id").toString() : UUID.randomUUID().toString()) //
+				.source(source) //
+				.create(true);
+	}
+
+	IndexRequest indexRequestFrom(SampleEntity entity) {
+
+		Map<String, Object> target = new LinkedHashMap<>();
+
+		if (StringUtils.hasText(entity.getId())) {
+			target.put("id", entity.getId());
+		}
+
+		if (StringUtils.hasText(entity.getType())) {
+			target.put("type", entity.getType());
+		}
+
+		if (StringUtils.hasText(entity.getMessage())) {
+			target.put("message", entity.getMessage());
+		}
+
+		target.put("rate", entity.getRate());
+		target.put("available", entity.isAvailable());
+
+		return indexRequest(target, INDEX, TYPE);
+	}
+
+	void bulkIndex(SampleEntity... entities) {
+
+		BulkRequest request = new BulkRequest();
+		Arrays.stream(entities).forEach(it -> request.add(indexRequestFrom(it)));
+
+		try (RestHighLevelClient client = TestUtils.restHighLevelClient()) {
+			client.bulk(request.setRefreshPolicy(RefreshPolicy.IMMEDIATE), RequestOptions.DEFAULT);
+		} catch (Exception e) {}
+	}
+
+	interface ReactiveSampleEntityRepository extends ReactiveCrudRepository<SampleEntity, String> {
+
+		Flux<SampleEntity> findAllByMessageLike(String message);
+
+		Flux<SampleEntity> findAllByMessageLikeOrderByRate(String message);
+
+		Flux<SampleEntity> findAllByMessage(String message, Sort sort);
+
+		Flux<SampleEntity> findAllByMessage(String message, Pageable pageable);
+
+		Flux<SampleEntity> findAllByMessage(Publisher<String> message);
+
+		@Query("{ \"bool\" : { \"must\" : { \"term\" : { \"message\" : \"?0\" } } } }")
+		Flux<SampleEntity> findAllViaAnnotatedQueryByMessageLike(String message);
+
+		Mono<SampleEntity> findFirstByMessageLike(String message);
+
+		Mono<Long> countAllByMessage(String message);
+
+		Mono<Boolean> existsAllByMessage(String message);
+
+		Mono<Long> deleteAllByMessage(String message);
+	}
+}