In the preceding example, we had a requirement for the History trait, which has an add() method. What would happen if the methods in different components have the same signatures and they clash? Let's try this:
trait Mystery { def add(): Unit = { System.out.println("Mystery added!") }}
We can now use this in our Persister trait:
trait Persister[T] { this: Database[T] with History with Mystery => def persist(data: T): Unit = { System.out.println("Calling persist.") save(data) add() }}
Of course, we will change all the classes that mix Persister in:
class FilePersister[T] extends Persister[T] with FileDatabase[T] with History with Mysteryclass MemoryPersister[T] extends Persister[T] with MemoryDatabase[T] with History ...
