Add new `@SubclassMapping` for creating Downcast mapping.
When a parent mapping method is annotated with `@SubclassMapping`
it will now generate an instanceof check inside the parent mapping
and generate the subclass mappings if they are not manually defined.
There is also `SubclassExhaustiveStrategy` for controlling what MapStruct should do in case the target type is abstract and there is no suitable way to create it.
New rules:
1. Constructor annotated with @Default (from any package) has highest precedence
2. If there is a single public constructor then it would be used to construct the object
3. If a parameterless constructor exists then it would be used to construct the object, and the other constructors will be ignored
Add a new EnumNamingStrategy SPI which can be used for customising the way enums are matched by name.
It is similar to the AccessorNamingStrategy such that it allows implementors to provide a custom way of defining a property.
Related to #796, #1220, #1789 and #1667
Add a new custom EnumTransformationStrategy SPI which can be used for providing custom way of name based mapping for enums.
Add 4 out of the box transformation strategies:
* prefix - add a prefix to the name based enum mapping
* stripPrefix - remove a prefix from the name based enum mapping
* suffix - add a suffix to the name based enum mapping
* stripSuffix - remove a suffix from the name based enum mapping
This can be achieved by using the new `EnumMapping`
e.g.
Add suffix `_TYPE` to all enums:
`@EnumMapping(nameTransformationStrategy = "suffix", configuration = "_TYPE")`
With this it would be possible to achieve what is needed in #796, #1220, #1789.
By default the constructor argument names are used to extract the target properties.
If a constructor is annotated with an annotation named `@ConstructorProperties` (from any package) then it would be used to extract the target properties.
If a mapping target has a parameterless empty constructor it would be used to instantiate the target.
When there are multiple constructors then an annotation named `@Default` (from any package) can be used to mark a constructor that should be used by default when instantiating the target.
Supports mapping into Java 14 Records and Kotlin data classes out of the box
