In this tutorial we will create a TransientComposite interface that ties all pieces together. The TransientComposite interface is a regular Java interface which extends the interfaces you want to expose from your domain model, and which uses various annotations to declare what Fragments to include. Fragments include Mixins, Concerns, SideEffects and Constraints. In this tutorial we will only use Mixins. When a TransientComposite is instantiated at runtime the framework will inspect the interface to determine what the TransientComposite instance should look like in terms of used Fragments.
In Polygene™ all method parameters are considered mandatory unless marked as @Optional. Therefore you can remove the null checks in the Mixin. If a null value is passed in an exception will be thrown by Polygene™.
Steps for this tutorial: