Actor Model

The actor model is a model for computation in which the "actor" is the primitive element of system design (in the actor model, "everything is an actor"). Each actor embodies processing, storage, and communication for a specific purpose.

Each actor in a system can:

Send messages to other actors
Create additional actors
Change internal state

Each actor has an address to which messages can be sent. A single address can represent multiple actors or a single actor can have multiple addresses.

Messages are delivered at most one time, and the order of delivery is not guaranteed; however, a message can contain an ordered sequence. Additionally, futures are actors that represents a computation result, potentially before it is computed, so that computation results can be made available at the time of need.