findAllById returns all requested documents.

Original Pull Request #2421
Closes #2417

Author: sothawo

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

@@ -147,9 +147,11 @@ public Iterable<T> findAllById(Iterable<ID> ids) {
 
 		Assert.notNull(ids, "ids can't be null.");
 
-		List<T> result = new ArrayList<>();
-		Query query = getIdQuery(ids);
-
+		List<String> stringIds = stringIdsRepresentation(ids);
+		Query query = getIdQuery(stringIds);
+		if (!stringIds.isEmpty()) {
+			query.setPageable(PageRequest.of(0, stringIds.size()));
+		}
 		List<SearchHit<T>> searchHitList = execute(
 				operations -> operations.search(query, entityClass, getIndexCoordinates()).getSearchHits());
 		// noinspection ConstantConditions
@@ -320,9 +322,7 @@ private IndexCoordinates getIndexCoordinates() {
 		return operations.getIndexCoordinatesFor(entityClass);
 	}
 
-	private Query getIdQuery(Iterable<? extends ID> ids) {
-		List<String> stringIds = stringIdsRepresentation(ids);
-
+	private Query getIdQuery(List<String> stringIds) {
 		return operations.idsQuery(stringIds);
 	}
 	// endregion

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

@@ -203,29 +203,27 @@ void shouldDeleteDocument() {
 		assertThat(entityFromElasticSearch).isNotPresent();
 	}
 
-	@Test // DATAES-82
+	@Test // DATAES-82, #2417
 	void shouldFindAllByIdQuery() {
 
-		// given
-		String documentId = nextIdAsString();
-		SampleEntity sampleEntity = new SampleEntity();
-		sampleEntity.setId(documentId);
-		sampleEntity.setMessage("hello world.");
-		sampleEntity.setVersion(System.currentTimeMillis());
-		repository.save(sampleEntity);
-
-		String documentId2 = nextIdAsString();
-		SampleEntity sampleEntity2 = new SampleEntity();
-		sampleEntity2.setId(documentId2);
-		sampleEntity2.setMessage("hello world.");
-		sampleEntity2.setVersion(System.currentTimeMillis());
-		repository.save(sampleEntity2);
+		// create more than 10 documents to see that the number of input ids is set as requested size
+		int numEntities = 20;
+		List<String> ids = new ArrayList<>(numEntities);
+		List<SampleEntity> entities = new ArrayList<>(numEntities);
+		for (int i = 0; i < numEntities; i++) {
+			String documentId = nextIdAsString();
+			ids.add(documentId);
+			SampleEntity sampleEntity = new SampleEntity();
+			sampleEntity.setId(documentId);
+			sampleEntity.setMessage("hello world.");
+			sampleEntity.setVersion(System.currentTimeMillis());
+			entities.add(sampleEntity);
+		}
+		repository.saveAll(entities);
 
-		// when
-		Iterable<SampleEntity> sampleEntities = repository.findAllById(Arrays.asList(documentId, documentId2));
+		Iterable<SampleEntity> sampleEntities = repository.findAllById(ids);
 
-		// then
-		assertThat(sampleEntities).isNotNull().hasSize(2);
+		assertThat(sampleEntities).isNotNull().hasSize(numEntities);
 	}
 
 	@Test

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

@@ -17,11 +17,13 @@
 
 import static org.assertj.core.api.Assertions.*;
 import static org.springframework.data.elasticsearch.core.query.Query.*;
+import static org.springframework.data.elasticsearch.utils.IdGenerator.*;
 
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
@@ -164,18 +166,27 @@ void findAllByIdByIdShouldCompleteIfIndexDoesNotExist() {
 		repository.findAllById(Arrays.asList("id-two", "id-two")).as(StepVerifier::create).verifyComplete();
 	}
 
-	@Test // DATAES-519
+	@Test // DATAES-519, #2417
 	void findAllByIdShouldRetrieveMatchingDocuments() {
 
-		bulkIndex(new SampleEntity("id-one"), //
-				new SampleEntity("id-two"), //
-				new SampleEntity("id-three")) //
-						.block();
+		// create more than 10 documents to see that the number of input ids is set as requested size
+		int numEntities = 20;
+		List<String> ids = new ArrayList<>(numEntities);
+		List<SampleEntity> entities = new ArrayList<>(numEntities);
+		for (int i = 0; i < numEntities; i++) {
+			String documentId = nextIdAsString();
+			ids.add(documentId);
+			SampleEntity sampleEntity = new SampleEntity();
+			sampleEntity.setId(documentId);
+			sampleEntity.setMessage("hello world.");
+			sampleEntity.setVersion(System.currentTimeMillis());
+			entities.add(sampleEntity);
+		}
+		repository.saveAll(entities).blockLast();
 
-		repository.findAllById(Arrays.asList("id-one", "id-two")) //
+		repository.findAllById(ids) //
 				.as(StepVerifier::create)//
-				.expectNextMatches(entity -> entity.getId().equals("id-one") || entity.getId().equals("id-two")) //
-				.expectNextMatches(entity -> entity.getId().equals("id-one") || entity.getId().equals("id-two")) //
+				.expectNextCount(numEntities) //
 				.verifyComplete();
 	}