Scala Reactive Programming

The Scala Promise API

Let's understand the Scala API for a Promise. Scala has a trait for a Promise in the scala.concurrent package, which is as follows:

trait Promise[T] extends AnyRef 

Scala Promise trait has the following important and frequently used functions:

trait Promise[T]{ 
  def success(value: T) : this.type 
  def failure(cause: Throwabale): this.type 
  def future: Future[T] 
} 

Its companion object is defined as shown here:

object Promise[T] { 
  def apply[T](): Promise[T] 
}