DATAES-791 - DocumentOperations.multiGet() implementations must return null values for not found entities.

Original PR: #428

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

@@ -16,7 +16,6 @@
 package org.springframework.data.elasticsearch.core;
 
 import java.util.List;
-import java.util.Optional;
 
 import org.springframework.data.elasticsearch.core.mapping.IndexCoordinates;
 import org.springframework.data.elasticsearch.core.query.BulkOptions;
@@ -121,7 +120,7 @@ public interface DocumentOperations {
 	 * @param query the query defining the ids of the objects to get
 	 * @param clazz the type of the object to be returned
 	 * @param index the index(es) from which the objects are read.
-	 * @return list of objects
+	 * @return list of objects, contains null values for ids that are not found
 	 */
 	<T> List<T> multiGet(Query query, Class<T> clazz, IndexCoordinates index);
 

src/main/java/org/springframework/data/elasticsearch/core/document/DocumentAdapters.java

@@ -118,16 +118,16 @@ public class DocumentAdapters {
 	 * Creates a List of {@link Document}s from {@link MultiGetResponse}.
 	 * 
 	 * @param source the source {@link MultiGetResponse}, not {@literal null}.
-	 * @return a possibly empty list of the Documents.
+	 * @return a list of Documents, contains null values for not found Documents.
 	 */
 	public static List<Document> from(MultiGetResponse source) {
 
 		Assert.notNull(source, "MultiGetResponse must not be null");
 
-		//noinspection ReturnOfNull
+		// noinspection ReturnOfNull
 		return Arrays.stream(source.getResponses()) //
 				.map(itemResponse -> itemResponse.isFailed() ? null : DocumentAdapters.from(itemResponse.getResponse())) //
-				.filter(Objects::nonNull).collect(Collectors.toList());
+				.collect(Collectors.toList());
 	}
 
 	/**
@@ -299,8 +299,7 @@ public class DocumentAdapters {
 		public Object get(Object key) {
 			return documentFields.stream() //
 					.filter(documentField -> documentField.getName().equals(key)) //
-					.map(DocumentField::getValue)
-					.findFirst() //
+					.map(DocumentField::getValue).findFirst() //
 					.orElse(null); //
 
 		}

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

@@ -240,6 +240,39 @@ public abstract class ElasticsearchTemplateTests {
 		assertThat(sampleEntities.get(1)).isEqualTo(sampleEntity2);
 	}
 
+	@Test // DATAES-791
+	public void shouldReturnNullObjectForNotExistingIdUsingMultiGet() {
+
+		// given
+		// first document
+		String documentId = randomNumeric(5);
+		SampleEntity sampleEntity1 = SampleEntity.builder().id(documentId).message("some message")
+				.version(System.currentTimeMillis()).build();
+
+		// second document
+		String documentId2 = randomNumeric(5);
+		SampleEntity sampleEntity2 = SampleEntity.builder().id(documentId2).message("some message")
+				.version(System.currentTimeMillis()).build();
+
+		List<IndexQuery> indexQueries = getIndexQueries(Arrays.asList(sampleEntity1, sampleEntity2));
+
+		operations.bulkIndex(indexQueries, index);
+		indexOperations.refresh();
+
+		// when
+		List<String> idsToSearch = Arrays.asList(documentId, randomNumeric(5), documentId2);
+		assertThat(idsToSearch).hasSize(3);
+
+		NativeSearchQuery query = new NativeSearchQueryBuilder().withIds(idsToSearch).build();
+		List<SampleEntity> sampleEntities = operations.multiGet(query, SampleEntity.class, index);
+
+		// then
+		assertThat(sampleEntities).hasSize(3);
+		assertThat(sampleEntities.get(0)).isEqualTo(sampleEntity1);
+		assertThat(sampleEntities.get(1)).isNull();
+		assertThat(sampleEntities.get(2)).isEqualTo(sampleEntity2);
+	}
+
 	@Test
 	public void shouldReturnObjectsForGivenIdsUsingMultiGetWithFields() {