Already covered in an earlier section was the capability to customize a ClassMap by using the customize(CustomMapper<A,B>), but suppose that you don’t want to register this custom mapper explicitly for every ClassMap pair; instead, you can register your CustomMapper instance on the MapperFactory so that whenever a mapping is requested with types compatible to those of your CustomMapper, it will be given control.
This can be done using the registerMapper(CustomMapper<A,B>) method on the MapperFactory, like so:
factory.registerMapper(new MyCustomMapper());
If you were to define your custom mapper like MyCustomMapper extends CustomMapper<?,?> (which is what you get by default if you’re accustomed to ignoring Java generics) then it would called for most all mapping requests, which is very likely not what you intended!
A Mapper (in the world of Orika) is something which copies the properties of one object instance to another. It works on already instantiated object instances which are passed in by reference. If you were expecting to replace one of the mapped object instances, a CustomMapper is not what you’re looking for; we suggest using a custom ObjectFactory or a CustomConverter instead—both of these return a new instance of the result object.