DATAMONGO-1287 - Optimizations in reading associations as constructor arguments.

As per discussion on the ticket we now omit looking up the value for an association being used as constructor argument as the simple check whether the currently handled property is a constructor argument is sufficient to potentially skip handling the value.

Related pull requests: #335, #322.

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

@@ -291,7 +291,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 				final MongoPersistentProperty property = association.getInverse();
 				Object value = dbo.get(property.getFieldName());
 
-				if (value == null || (entity.isConstructorArgument(property) && accessor.getProperty(property) != null)) {
+				if (value == null || entity.isConstructorArgument(property)) {
 					return;
 				}