Type Members

1.  final class TypeId extends Annotation with StaticAnnotation

   Annotation allowing for customizing the type id that automatically derived encoder/decoders for abstract data types produce/consume.

   Annotation allowing for customizing the type id that automatically derived encoder/decoders for abstract data types produce/consume.

   By default the derived encoders and decoders for ADTs serialize the short class name of an ADT instance in order to let the decoder now, which sub-type to deserialize.

   This notation allows for customizing the type id that is used to identify an ADT sub-type in the encoding and offers two choices: A String or an integer number (Int/Long) value.

   Relying on strings makes the serialization more descriptive but is more verbose on the wire. Relying on numbers makes the serialization very compact but less descriptive.

   If necessary styles could also be mixed within a single ADT, even though this is not recommended (for consistency/clarity only, there is no technical reason).

   The following example shows such an (otherwise not recommended) mixed setup for illustrating the different style of using this annotation:

   sealed trait Animal
   object Animal {
     @TypeId("D") // default would be "Dog", but we want sth shorter
     final case class Dog(name: String, age: Int)
   
     @TypeId(2)
     final case class Cat(name: String, age: Int, weight: Option[Double])
   
     // if no @TypeId is given, the short type name is used, in this case "Mouse"
     final case class Mouse(name: String, size: Int)
   }