Actor Composition

This lecture discusses the structurally typed nature of Actors as implemented in untyped Akka. In particular, you learn:

• that the type of an Actor is defined by the set of messages it accepts
• that the type of the ActorRef can fundamentally not express in which state the Actor currently is
• how these liberties allow generic transformations of message streams to be implemented, for example changing message rate or timing
• how the frequently encountered request–response pattern is encoded directly in Akka’s ask operator
• that including reply-to addresses allows dynamic composition structures
• how to implement non-blocking result aggregation using Futures
• how to delegate risky operations
• how to adapt Actor protocols by placing a façade between sender and receiver