DATAMONGO-329 - Fixed Collection and Map value handling for more open properties.

The decision whether a property value was handled as Collection or Map was based on inspecting the property's type which failed for classes using very open property declarations such as:

class MyClass {

  Object something;
}

We now rather inspect the value type instead of the property.

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

@@ -446,16 +446,16 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 		}
 
 		String name = prop.getFieldName();
+		TypeInformation<?> valueType = ClassTypeInformation.from(obj.getClass());
+		TypeInformation<?> type = prop.getTypeInformation();
 
-		if (prop.isCollectionLike()) {
+		if (valueType.isCollectionLike()) {
 			DBObject collectionInternal = createCollection(asCollection(obj), prop);
 			dbo.put(name, collectionInternal);
 			return;
 		}
 
-		TypeInformation<?> type = prop.getTypeInformation();
-
-		if (prop.isMap()) {
+		if (valueType.isMap()) {
 			BasicDBObject mapDbObj = new BasicDBObject();
 			writeMapInternal((Map<Object, Object>) obj, mapDbObj, type);
 			dbo.put(name, mapDbObj);
@@ -596,7 +596,8 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 							writeCollectionInternal(asCollection(val), propertyType.getMapValueType(), new BasicDBList()));
 				} else {
 					DBObject newDbo = new BasicDBObject();
-					writeInternal(val, newDbo, propertyType);
+					TypeInformation<?> valueTypeInfo = propertyType.isMap() ? propertyType.getMapValueType() : ClassTypeInformation.from(Object.class);
+					writeInternal(val, newDbo, valueTypeInfo);
 					dbo.put(simpleKey, newDbo);
 				}
 			} else {

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

@@ -817,7 +817,32 @@ public class MappingMongoConverterUnitTests {
 		assertThat(result, is(dbObject));
 	}
 	
-	
+	/**
+	 * @see DATAMONGO-329
+	 */
+	@Test
+	public void writesMapAsGenericFieldCorrectly() {
+		
+		Map<String, A<String>> objectToSave = new HashMap<String, A<String>>();
+		objectToSave.put("test", new A<String>("testValue"));
+
+		A<Map<String, A<String>>> a = new A<Map<String, A<String>>>(objectToSave);
+		DBObject result = new BasicDBObject();
+
+		converter.write(a, result);
+		
+		assertThat((String) result.get(DefaultMongoTypeMapper.DEFAULT_TYPE_KEY), is(A.class.getName()));
+		assertThat((String) result.get("valueType"), is(HashMap.class.getName()));
+		
+		DBObject object = (DBObject) result.get("value");
+		assertThat(object, is(notNullValue()));
+		
+		DBObject inner = (DBObject) object.get("test");
+		assertThat(inner, is(notNullValue()));
+		assertThat((String) inner.get(DefaultMongoTypeMapper.DEFAULT_TYPE_KEY), is(A.class.getName()));
+		assertThat((String) inner.get("valueType"), is(String.class.getName()));
+		assertThat((String) inner.get("value"), is("testValue"));
+	}
 	
 	class GenericType<T> {
 		T content;
@@ -911,6 +936,17 @@ public class MappingMongoConverterUnitTests {
 		@Id
 		BigInteger id;
 	}
+
+	class A<T> {
+
+		String valueType;
+		T value;
+
+		public A(T value) {
+			this.valueType = value.getClass().getName();
+			this.value = value;
+		}
+	}
 	
 	private class LocalDateToDateConverter implements Converter<LocalDate, Date> {