Slides from Jetbrains/Akka webinar about Akka Actors with Java 8 2016-09-13

1. Introduction to
Akka Actors
with Java 8

2. Mememememe
memememe

3. Instead of more Ghz
more cores
source: http://queue.acm.org/detail.cfm?id=2181798

4. Another thing that has changed

5. Build powerful concurrent &
distributed applications
more easily.
Akka is a toolkit and runtime
for building highly concurrent,
distributed, and resilient
message-driven applications
on the JVM

6. ”The actor model in computer science is a
mathematical model of concurrent computation
that treats actors as the universal primitives of
concurrent computation. ”
Wikipedia
The Actor Model

7. An Actor
and acts on them by:
• Sending messages
• Changing its state
• Changing its behavior
• Creating more actors
receives messages

8. The Actor hierarchy
/user
system.actorOf(props, ”my-actor”)
/user/my-actor
getContext()
.actorOf(…, ”my-child”)
/user/my-actor/my-child

9. Supervision
/user
/user/my-actor
🌋

10. Actor
Lifecycle
actorOf()
New instance -
restarted
restart
resume
stop
ActorRef

11. Dispatch (Actor Execution)
Actor-a
Actor-b
Thread 1
Thread 2
b
b
ba a
a
Time

12. Blocking
Actor-a
Actor-b
Thread 1
Thread 2
b b
a
Time
a
Actor-c

13. Dos and don’ts
Don’t: Put every actor under /user
Separate parts using supervisors so they can fail independently
Do: Isolate blocking
Put blocking logic on its own thread based dispatcher
Don’t: Write all your logic inside your actors
Make what is possible ”regular” OO logic that you can set up and unit
test synchronously
Do: Make all messages immutable
Or else there will be concurrency/visibility problems
Do: Put asynchronous boundaries where it makes sense
Three tier where each tier is an actor is probably not that useful

14. What more is there?
Akka Cluster
Akka Streams
and cluster tools
async & back-pressured

15. Get started
Learn more - the docs:
http://akka.io/docs
Get help:
gitter channel:
https://gitter.im/akka/akka
mailing list:
https://groups.google.com/forum/#!forum/akka-user
Project with samples:
https://github.com/johanandren/akka-actor-java8-webinar