Learning Concurrent Programming in Scala - Second Edition

Chapter 10.  Reactors

	"Simplicity is prerequisite for reliability."
	--Edsger W. Dijkstra

Location-transparency, serializable event-handling, and non-blocking semantics of sends, make the actor model a powerful foundation for building distributed systems. However, the actor model has several important limitations, which only become apparent when building larger systems. First, actors cannot simultaneously contain multiple message entry points. All messages must arrive through the same receive block. Consequently, two different protocols cannot reuse the same message type, and must be aware of each other. The main example where we saw this was the Identify message, which required users to incorporate a unique token into the message. Second, actors ...