title: How to set up Akka actors to process messages in serial and in parallel based on predicate?
body: <p>How can I process in serial and in parallel these messages based on even numbers? For instance when <code>i</code> is 2,4,6,8... to process the messages in parallel.</p>
  
  <p>I think that the messages are processed in serial anywise but how can I differentiate to process them in parallel?</p>
  
  <pre><code>for(i &lt;- 1 to 100) {
    greeter ! WhoToGreet("message: " + i)
    inbox.send(greeter, Greet) 
    val Greeting(message) = inbox.receive(10.seconds)
    println(message)
  }
  </code></pre>
  
  <p>I've changed <code>application.conf</code> to be as follows:</p>
  
  <pre><code>akka {
    actor{
      default-dispatcher {
        type = Dispatcher
        executor = "thread-pool-executor"
        throughput = 100    
        fork-join-executor {
          parallelism-min = 2
          parallelism-factor = 2.0
          parallelism-max = 8
        }
      }
    }
  }
  </code></pre>
  
  <p>but I'm not sure if that's the way or by using par.</p>
  
  <p>I there any way to see when are processed in serial and when in parallel?</p>