Frequently Asked Questions

Both Mappie and MapStruct run before or during the compilation of your source code. Mappie is implemented as a Kotlin compiler Plugin, while MapStruct is based on kapt, which is in maintenance mode.

Mappie generates Kotlin intermediate code, while MapStruct generates Java code. Combining Java code with Kotlin is a potential risk for nullability issues at run-time. The annotation based approach of MapStruct also has usability issues, as there are no syntactical references to the objects being mapped, disallowing refactoring support from IDE's.

Both Mappie and MapStruct have excellent run-time performance.

Both Mappie and ShapeShift are built for the Kotlin ecosystem. Mappie generates code at compile-time, while ShapeShift resolves its mappings via reflection. This results in a big performance penalty.

The design choices of ShapeShift and Mappie are different. For example, ShapeShift requires the target classes to have a no-arg constructor, and mapping purely on properties, limiting the flexibility of your code base.

As Mappie in its early stages, ShapeShift does have more built-in support for advanced use-cases while Mappie sometimes needs to fall back on more generic operations.