hiyingnn / mapstruct-demo

Handling null cases

Target data-type	Null mapping	Comments
String	null -> ''	Fallback is empty string
Collection	null -> List.of(), Set.of()	Fallback is empty collection
enum	1. null -> enum.DEFAULT 2.null -> null	(1) Fallback value for null should be the default enum. However since there are some enums that do not have fallback values, may be good to be consistently use (2) mapping, null -> null
Object	1. null -> new Object() with default values 2. null -> null	(1) For certain objects with sensible defaults (PartialDate="00-00-00", Long="0L"), it may make sense for it to have fallback values. However, many objects would not have fallback values (e.g., UserInput) and it is not trivial to recursively set its default values. In that case, it may make more sense to just consistently use (2) mapping, null -> null

Mapstruct mapping configurations