Play-nicewith-AKKA

AKKA implementation for Play 1.2.x

Update!

I have removed the need to call play with the config.file system property. Instead I am using: ConfigFactory.parseFile(Play.getFile("conf/reference.conf"));

Overview

This project provides a very basic skeleton for integrating AKKA with Play 1.2.x. Everything is included in the project - to run do the following:

• in a command prompt run play deps - this will get the AKKA client jar
• call play run

The database is in memory and so will be cleared every time you run the project.

Setup Guide (If creating a project manually)

• In your dependencies.yml file include the line

  com.typesafe.akka -> akka-actor_2.10 2.1.0 // this was the latest version at time of writing

• execute from the command line play deps to download the relevant libraries into your lib folder

• do some IDE goodness to get the library dependencies in setup in your conf directory a reference.conf file (this will contain config info for akka on start) - look at: http://doc.akka.io/docs/akka/2.1.0/general/configuration.html

• add "-Dconfig.file=reference.conf" to your VM options

• Have a static class of AppContext or similar to load in the AkkaSystem - this is just so that you create once and can reference from anywhere.

• Load the AKKA system with:

    Config config = ConfigFactory.load();
    public static final notificationSystem = ActorSystem.create("notification", config);
  

That should be enough to get running, then you just have to create some Actors to do your bidding.

I also got JPA working - if you try and access your models and lookup data, you will end up with an Uninitialised Entity Manager error.

Here is some example code for an actor with JPA access:

    @Override
    public void onReceive(Object o) throws Exception {
	    if (o instanceof SomeMessageType) { // create your own serializable class to transfer message data
	        SomeMessageType message = (SomeMessageType) o;
	        JPAPlugin.startTx(true); // true is to start this as a readonly transaction
	        // Do all the JPA goodness
	    
	        JPAPlugin.closeTx(false); // false is for rollback - I use this because I am doing a readonly transaction
	    
	    } else {
	        unhandled(o);
	    }
    }

Hope this helps. I spent a good few hours trying to get everything working. I am now able to structure my async tasks rather than just spit out to Play Jobs.