The proper way to handle problems inside akka actors is not to throw an exception but rather to set supervisor hierarchies “Throwing an exception in concurrent code (let’s assume we are using non-linked actors), will just simply blow up the thread that currently executes the actor. There is no way to find out that things … Read more
This answer isn’t really mine. It was produced by Viktor Klang (of Akka fame) with the help of David Pollak (of Lift fame), Jason Zaugg (of Scalaz fame), Philipp Haller (of Scala Actors fame). All I’m doing here is formatting it (which would be easier if Stack Overflow supported tables). There are a few places … Read more
Well, there isn’t. There is just Actor model, and Akka actors and Scala actors are two implementations of that model. All Actor model says that your concurrency primitives are actors, which can: receive a message and decide what to do next depending on the content of the message, including: send messages to any actors they … Read more
Shamelessly copied [awesome] official doc (look Send messages section for more): Messages are sent to an Actor through one of the following methods. ! means “fire-and-forget”, e.g. send a message asynchronously and return immediately. Also known as tell. ? sends a message asynchronously and returns a Future representing a possible reply. Also known as ask.
Without going into the details (about which I know too little in the case of Node.js), the main difference is that Node.js supports only concurrency without parallelism while Akka supports both. Both systems are completely event-driven and can scale to large work-loads, but the lack of parallelism makes it difficult in Node.js (i.e. parallelism is … Read more
It is hard to tell at this point because Reactor is still a sketch and I (Akka tech lead) do not have insight into where it will go. It will be interesting to see if Reactor becomes a competitor to Akka, we are looking forward to that. As far as I can see, from your … Read more
Disclaimer: I am the PO for Akka Erlang does copy-on-send – Akka uses shared memory (immutable objects) for in-VM sends Erlang does per-process GC – Akka uses JVM GCs Erlang has OTP – Akka integrates with the entire Java ecosystem (Apache Camel, JAX-RS, etc etc) Erlang does the process scheduling for you – Akka allows … Read more
First off the “older” message systems (MQ) are older in implementation but they are a newer in engineering idea of: transactional persistent queues. Scala Actors and Akka maybe a newer implementation but are built on an older concurrency model of Actors. The two models however end up being very similar in practice because they both … Read more
Both stop and PoisonPill will terminate the actor and stop the message queue. They will cause the actor to cease processing messages, send a stop call to all its children, wait for them to terminate, then call its postStop hook. All further messages are sent to the dead letters mailbox. The difference is in which … Read more
I have used it so far in two real projects very successfully. both are in the near real-time traffic information field (traffic as in cars on highways), distributed over several nodes, integrating messages between several parties, reliable backend systems. I’m not at liberty to give specifics on clients yet, when I do get the OK … Read more