DATAMONGO-1263 - Index resolver considers generic type argument of collection elements.

We now consider the potential generic type argument of collection elements. 
Prior to this change an index within List<GenericWrapper<ConcreteWithIndex>> would not have been resolved.

Original pull request: #312.

Author: christophstrobl

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/MongoPersistentEntityIndexResolver.java

@@ -108,7 +108,7 @@ public void doWithPersistentProperty(MongoPersistentProperty persistentProperty)
 
 				try {
 					if (persistentProperty.isEntity()) {
-						indexInformation.addAll(resolveIndexForClass(persistentProperty.getActualType(),
+						indexInformation.addAll(resolveIndexForClass(persistentProperty.getTypeInformation().getActualType(),
 								persistentProperty.getFieldName(), root.getCollection(), guard));
 					}
 
@@ -135,7 +135,7 @@ public void doWithPersistentProperty(MongoPersistentProperty persistentProperty)
 	 * @return List of {@link IndexDefinitionHolder} representing indexes for given type and its referenced property
 	 *         types. Will never be {@code null}.
 	 */
-	private List<IndexDefinitionHolder> resolveIndexForClass(final Class<?> type, final String path,
+	private List<IndexDefinitionHolder> resolveIndexForClass(final TypeInformation<?> type, final String path,
 			final String collection, final CycleGuard guard) {
 
 		MongoPersistentEntity<?> entity = mappingContext.getPersistentEntity(type);
@@ -153,8 +153,8 @@ public void doWithPersistentProperty(MongoPersistentProperty persistentProperty)
 
 				if (persistentProperty.isEntity()) {
 					try {
-						indexInformation.addAll(resolveIndexForClass(persistentProperty.getActualType(), propertyDotPath,
-								collection, guard));
+						indexInformation.addAll(resolveIndexForClass(persistentProperty.getTypeInformation().getActualType(),
+								propertyDotPath, collection, guard));
 					} catch (CyclicPropertyReferenceException e) {
 						LOGGER.info(e.getMessage());
 					}

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/index/MongoPersistentEntityIndexResolverUnitTests.java

@@ -853,6 +853,19 @@ public void shouldOnlyConsiderEntitiesAsPotentialCycleCandidates() {
 
 		}
 
+		/**
+		 * @see DATAMONGO-1263
+		 */
+		@Test
+		public void shouldConsiderGenericTypeArgumentsOfCollectionElements() {
+
+			List<IndexDefinitionHolder> indexDefinitions = prepareMappingContextAndResolveIndexForType(EntityWithGenericTypeWrapperAsElement.class);
+
+			assertThat(indexDefinitions, hasSize(1));
+			assertThat((String) indexDefinitions.get(0).getIndexOptions().get("name"),
+					equalTo("listWithGeneircTypeElement.entity.property_index"));
+		}
+
 		@Document
 		static class MixedIndexRoot {
 
@@ -1028,6 +1041,15 @@ public static class AlternatePathToNoCycleButIndenticallNamedPropertiesDeeplyNes
 			NoCycleButIndenticallNamedPropertiesDeeplyNested propertyWithIndexedStructure;
 		}
 
+		static class GenericEntityWrapper<T> {
+			T entity;
+		}
+
+		@Document
+		static class EntityWithGenericTypeWrapperAsElement {
+			List<GenericEntityWrapper<DocumentWithNamedIndex>> listWithGeneircTypeElement;
+		}
+
 	}
 
 	private static List<IndexDefinitionHolder> prepareMappingContextAndResolveIndexForType(Class<?> type) {