Scala:使用泛型case类的模式匹配
是否可以匹配泛型案例类? 其思想是使用一些通用案例类作为参与者之间的消息 这就是我的方法:有没有办法让这成为可能Scala:使用泛型case类的模式匹配,scala,generics,pattern-matching,Scala,Generics,Pattern Matching,是否可以匹配泛型案例类? 其思想是使用一些通用案例类作为参与者之间的消息 这就是我的方法:有没有办法让这成为可能 case class EbTreeDataObject[T](uId: Long, changeId: Long, payload:Option[T]) case class InsertNewObject[T](newObject: EbTreeDataObject[T]) case class UpdateObject[T](changedObject: EbTreeDataOb
case class EbTreeDataObject[T](uId: Long, changeId: Long, payload:Option[T])
case class InsertNewObject[T](newObject: EbTreeDataObject[T])
case class UpdateObject[T](changedObject: EbTreeDataObject[T])
class TreeActor[T](maxSynchroWait:Int,communication:CommunikationLayer[T]) extends Actor {
var uIdTree = new EbTree[EbTreeDataObject[T]]
var changeIdTree = new EbTree[EbTreeDataObject[T]]
override def receive: Receive = {
//basic tree operations
case InsertNewObject(newObject: EbTreeDataObject[T]) =>
//insert element in tree
case UpdateObject(newObject: EbTreeDataObject[T]) =>
//update object
case RemoveObject(removedObject: EbTreeDataObject[T]) =>
//remove object
此构造在编译时出错:
Error:(32, 37) pattern type is incompatible with expected type;
found : model.EbTreeDataObject[T]
required: model.EbTreeDataObject[Any]
Note: T <: Any, but class EbTreeDataObject is invariant in type T.
You may wish to define T as +T instead. (SLS 4.5)
case InsertNewObject(newObject: EbTreeDataObject[T]) =>
错误:(32,37)模式类型与预期类型不兼容;
已找到:model.EbTreeDataObject[T]
必需:model.EbTreeDataObject[任何]
注:T
感谢您的帮助为什么不按照编译器的建议执行:
case class EbTreeDataObject[+T](uId: Long, changeId: Long, payload: Option[T])
为什么不按照编译器的建议去做呢:
case class EbTreeDataObject[+T](uId: Long, changeId: Long, payload: Option[T])
Thx但是[+T]和[T]之间的区别是什么?
[T]
只表示允许的“T”类型,其中“[+T]”表示属于T
子类型的任何东西,a Thx但是[+T]和[T]之间的区别是什么?[T]
表示只允许的“T”类型,其中“[+T]”表示属于T
子类型的任何东西,a