Immutable Objects

Immutable objects are objects whose state cannot be changed after they are created. Their state is set during construction and cannot be changed.

While the object itself is immutable, it can provide an immutable setter method, also known as a wither method. Rather than returning void or itself, the wither method returns a new instance of the object with the requested change.

Mapper supports these immutable setters, as well as immutable adders and removers. The caveat is that the host object that contains the immutable object must have a setter method that accepts the new instance. Otherwise, Mapper will give a warning.

note

Mapping using property paths does not support immutable setters.