在 scala 中实现泛型方法的正确方法是什么

Question

I have this Datasource trait

trait DataSource {
  def insert[T](foo: Foo): Either[Exception, Future[T]]
}

Then I create an implementation like:

class MongoDataSource(collection: MongoCollection[Document]) extends DataSource {

  override def insert[ManagedObject](doc: ManagedObject): Either[Exception, Future[ManagedObject]] = {
    Right(Future(new ManagedObject("")))
  }
}

I got error:

class type required but ManagedObject found
    Right(Future(new ManagedObject("")))

Answer 1

I think this might be what you want.

trait DataSource[T] {  //move type parameter to the trait
  def insert(foo: T): Either[Exception, Future[T]]
}

class MongoDataSource(collection: MongoCollection[Document]) extends DataSource[ManagedObject] {
  override def insert(doc: ManagedObject): Either[Exception, Future[ManagedObject]] = {
    Right(Future(new ManagedObject("")))
  }
}