DATAMONGO-1423 - Map keys now get registered conversions applied for Updates.

We now pipe map keys through the potentially registered conversions when mapping Updates.

Orignal pull request: #365.

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2015 by the original author(s).
+ * Copyright 2011-2016 by the original author(s).
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,6 +20,7 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -1001,11 +1002,13 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 		}
 
 		if (obj instanceof Map) {
-			DBObject result = new BasicDBObject();
+			Map<Object, Object> converted = new LinkedHashMap<Object, Object>();
+
 			for (Map.Entry<Object, Object> entry : ((Map<Object, Object>) obj).entrySet()) {
-				result.put(entry.getKey().toString(), convertToMongoType(entry.getValue(), typeHint));
+				converted.put(convertToMongoType(entry.getKey()), convertToMongoType(entry.getValue(),
+						typeHint != null && typeHint.getMapValueType() != null ? typeHint.getMapValueType() : typeHint));
 			}
-			return result;
+			return new BasicDBObject(converted);
 		}
 
 		if (obj.getClass().isArray()) {

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/convert/UpdateMapperUnitTests.java

@@ -857,6 +857,32 @@ public class UpdateMapperUnitTests {
 		assertThat($set.get("concreteValue.name"), nullValue());
 	}
 
+	/**
+	 * @see DATAMONGO-1423
+	 */
+	@Test
+	public void mappingShouldConsiderCustomConvertersForEnumMapKeys() {
+
+		CustomConversions conversions = new CustomConversions(
+				Arrays.asList(AllocationToStringConverter.INSTANCE, StringToAllocationConverter.INSTANCE));
+
+		MongoMappingContext mappingContext = new MongoMappingContext();
+		mappingContext.setSimpleTypeHolder(conversions.getSimpleTypeHolder());
+		mappingContext.afterPropertiesSet();
+
+		MappingMongoConverter converter = new MappingMongoConverter(mock(DbRefResolver.class), mappingContext);
+		converter.setCustomConversions(conversions);
+		converter.afterPropertiesSet();
+
+		UpdateMapper mapper = new UpdateMapper(converter);
+
+		Update update = new Update().set("enumAsMapKey", Collections.singletonMap(Allocation.AVAILABLE, 100));
+		DBObject result = mapper.getMappedObject(update.getUpdateObject(),
+				mappingContext.getPersistentEntity(ClassWithEnum.class));
+
+		assertThat(result, isBsonObject().containing("$set.enumAsMapKey.V", 100));
+	}
+
 	static class DomainTypeWrappingConcreteyTypeHavingListOfInterfaceTypeAttributes {
 		ListModelWrapper concreteTypeWithListAttributeOfInterfaceType;
 	}
@@ -1083,6 +1109,7 @@ public class UpdateMapperUnitTests {
 	static class ClassWithEnum {
 
 		Allocation allocation;
+		Map<Allocation, String> enumAsMapKey;
 
 		static enum Allocation {