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Diffstat (limited to 'shared/src/main/scala/annotations.scala')
| -rw-r--r-- | shared/src/main/scala/annotations.scala | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/shared/src/main/scala/annotations.scala b/shared/src/main/scala/annotations.scala new file mode 100644 index 0000000..9d35d16 --- /dev/null +++ b/shared/src/main/scala/annotations.scala @@ -0,0 +1,22 @@ +package spray.json + +import scala.annotation.StaticAnnotation + +/** An annotation that designates that a sealed trait is a generalized algebraic + * datatype (GADT), and that a type field containing the serialized childrens' + * types should be added to the final JSON objects. + * + * Note that by default all sealed traits are treated as GADTs, with a type + * field called `type`. This annotation enables overriding the name of that + * field and is really only useful if a child itself has a field called `type` + * that would result in a conflict. + * + * Example: + * {{{ + * // the JSON field "kind" will contain the actual type of the serialized child + * @gadt("kind") sealed abstract class Keyword(`type`: String) + * case class If(`type`: String) extends Keyword(`type`) + * }}} + * @param typeFieldName the name of the field to inject into a serialized JSON + * object */ +final class gadt(val typeFieldName: String = "type") extends StaticAnnotation |